The Art of Phacoemulsification

The Ar Artt of Phacoemulsification The Ar t of Phacoemulsification Editors Keiki R Mehta MD MBBS DOMS MS (Ophth) FORC...

Author: Keika R. Mehta | John J. Alpar

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The Ar Artt of Phacoemulsification

The Ar t of Phacoemulsification Editors Keiki R Mehta MD MBBS DOMS MS (Ophth) FORCE (India) DO (Ireland)

DO (London) FRSH (London) FIOS (USA) Medical Director: Mehta International Eye Institute Chief: Ophthalmic Services, Colaba Eye Hospital Chief: Surgical Services, Netra Rukshak, Rural Eye Services Wing, Mumbai, India Head: Eye Department, Breach Candy Hospital and Research Centre, Mumbai Hon Ophthalmic Consultant Surgeon: Armed Forces, India Hon Ophthalmic Consultant to the Governor of Maharashtra Past President: All India Ophthalmological Society, Intraocular Implant Society, India and

John J Alpar MD FACS FICS PA Diplomate: American Board of Ophthalmology Diplomate: Hungarian Board of Ophthalmology Clinical Professor: Texas Tech University School of Medicine Medical Director: Panhandle Ophthalmological Research Foundation, Texas, USA Fellow: American Academy of Ophthalmology, Saint Luke Eye Institute Amarilo, Texas, USA

JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD New Delhi

Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd B-3 EMCA House, 23/23B Ansari Road, Daryaganj Post Box 7193, New Delhi 110 002, India Phones: 3272143, 3272703, 3282021 Fax: 011-3276490 E-mail: [email protected] Visit our web site: http://www.jpbros.20m.com

Branches • 202 Batavia Chambers, 8 Kumara Kruppa Road, Kumara Park East, Bangalore 560 001, Phones: 2285971, 2382956 Tele Fax: 2281761 E-mail: [email protected] • 1A Indian Mirror Street, Wellington Square Calcutta 700 013, Phone: 2451926 Fax: 2456075 E-mail: [email protected] • 282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza Pantheon Road, Chennai 600 008, Phone: 8262665 Fax: 8262331 E-mail: [email protected] • 106 Amit Industrial Estate, 61 Dr SS Rao Road, Near MGM Hospital Parel, Mumbai 400 012 , Phones: 4124863, 4104532 Fax: 4160828 E-mail: [email protected]

The Art of Phacoemulsification © 2001, Editors All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the editors and the publisher. This book has been published on good faith that the material provided by editors is original. Every effort is made to ensure accuracy of material, but the publisher, printer and editors will not be held responsible for any inadvertent error(s). In case of any dispute, all legal matters to be settled under Delhi jurisdiction only.

First Edition: 2001 ISBN 81-7179-790-3

Publishing Director: RK Yadav Typeset at JPBMP typesetting unit Printed at Gopsons Paper Ltd., Noida

Contributors

Alpar John J

MD FACS FICS PA

Garry P Condon

MD

Clinical Professor Texas Tech University School of Medicine Medical Director Panhandle Ophthalmological Research Foundation, Texas, USA Fellow American Academy of Ophthalmology Saint Luke Eye Institute Amarilo, Texas, USA

Director, Division of Glaucoma Allegheny General Hospital MCP Hahnaman University Pittsburgh, Pennsylvania, USA

Fine Howard I

Masket Samuel

MD

Clinical Assistant Professor Oregon Health Sciences University Portland, Oregon Oregon Eye Assocciates, Eugene Oregon, USA

Richard S Hoffman

MD

Oregon Eye Associates, Eugene, Oregon, USA

Fry Luther L

MD

Director and Chief Fry Associates PA/Ophthalmology 310 East Walnut, Garden City, Kansas, USA

Jonathan P Ellant

MD

Chief St Clare’s Hospital and Health Care Center Assistant Professor Mt Sinai School of Medicine New York, USA

Luis W Lu

MD FACS

Instructor University of Pittsburgh School of Medicine ELK County Eye Clinic Center for Advanced Eye Care St. Marys, Pennsylvania, USA

Louis D Nichamin

MD

Medical Director Laurel Eye Clinic Brookville, Pennsylvania, USA MD

Clinical Professor Jules Stein Eye Institute UCLA, Los Angeles, USA

Allen David E

MD FRCOphth

Consultant Ophthalmologist City Hospitals, Sunderland Sunderland Eye Infirmary Queen Alexandra Road, Sunderland, UK

Arnott Eric J

MD DO FRCS FRCOphth

Consultant Ophthalmologist Arnott Eye Centre, Trottsford Farm Headley, Nr Brandon Hamshire, UK

Packard Richard

MD FRCS FRCOphth

Ophthalmic Surgeon Prince Charles Eye Unit Windsor, UK

Durval Carvalho M

MD

Chief Cataract Department Centro Brasileiro de Cirurljia, de Olhros (CBCO); Member Conselho da Sociedade Brasileria de Cataracta, Brazil

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Durval Carvalho M Jr

P HACOEMULSIFICATION MD

Doctorate, Departamento de Oftalmologia da Universidade Sao Paulo (USP) Member, Departamento de Oftalmologia da Universidade Federal de Goias (UFG), Brazil

Arshinoff Steve A

MD FRCSC

Enrique Chipont

MD PhD

Ophthalmic Surgeon Instituto Oftalmologico de Alicante IOIS General Secretary, AVDA–DE Denia, Alicante, Spain

Agarwal Amar

MS FRCS FRCOphth (Lon)

Ophthalmic Surgeon York Finch Eye Associates 2115 Finch Avenue W, Suite 316, Toronto, Ontario, Canada

Consultant Ophthalmic Surgeon Dr Agarwal’s Eye Institute 13 Cathedral Road, Chennai, India

Davis Peter L

Consultant Ophthalmic Surgeon Dr Agarwal’s Eye Institute 13 Cathedral Road, Chennai, India

MD, FRCS (C)

Senior Ophthalmologist North Okanagan Health District Vernon BC V1T 2M9, Canada

Aron-Rosa Danielle

MD

Ophthalmic Surgeon 28 Ave, Raphael, Paris, France

Joseph Leon A

MD

Consulting Surgeon Polyclinique Comiti, Dept of Ophthalmology 20000, Ajaccio, France

Claude S Leon

MD

MD

Professor, Dipartimento Di Discipline Chirurgiche, Via Vettoio, Blocco 117A, 6710 Coppito (AQ), Italy

Leopoldo Spadea

MD

University of L’AQuila S Salvatore Hospital, L’AQuila, Italy

Luigi Mosca

MD

University of L’AQuila S Salvatore Hospital, L’AQuila, Italy

Oshika Tetsuro

MD

Ophthalmic Surgeon University of Tokyo School of Medicine 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan

Alio Jorge L

MD (Path) FRSH (Lon) DO

Agarwal Jaiveer

MD

Director and Chief Dr Agarwal’s Eye Institute 13 Cathedral Road, Chennai, India

Agarwal Sunita

MD FSVH (WG) FRSH (Lon) DO

Director and Chief Dr Agarwal’s Eye Institute 15 Eagle Street, Bangalore, India

Agarwal T

MD

Consultant Ophthalmic Surgeon Dr Agarwal’s Eye Institute 13 Cathedral Road, Chennai, India

France

Emilio Balestrazzi

Agarwal Athiya

MD PhD

Professor and Chairman of Ophthalmology, Medical Director Instituto Oftalmologico de Alicante IOIS General Secretary, AVDA–DE Denia, Alicante, Spain

Col Akhil Bharadwaj

MD

Chief Eye Surgeon, Armed Forces, Asvini, Colaba Mumbai, India

Dada Vijay K

MD DOMS

Chief and Professor Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Namrata Sharma

MD

Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Tanuj Dada

Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Kapoor Shashi

MD

Consulting Ophthalmic Surgeon Kapoor Eye Clinic, 409 Om Chambers Kemps Corner Mumbai, India

C ONTRIBUTORS Kelkar Shrikant

MD

Murthy KR

MD

Director and Chief National Institute of Ophthalmology 1187/30, Ghole Road, Shivaji Nagar Pune, India

Consultant Ophthalmic Surgeon Prabha Eye Clinic 504, 40th Cross, 8th Block Jayanagar, Bangalore, India

Lahane Tatyarao P

Sachdev Mahipal S

MD

Professor and Head Grant Medical College JJ Group of Hospitals Mumbai, India

Maniar Ranjit H

MD

Head, Shushrusha Hospital, Mumbai Honorary Ophthalmic Consultant Jankikund Hospital, Chitrakoot

Mehta Cyres K

MD

Consultant Ophthalmologist Mehta International Eye Institute Colaba Eye Hospital Mumbai, India

Mehta Keiki R

MD

Medical Director Mehta International Eye Institute Chief, Ophthalmic Services Colaba Eye Hospital Chief, Surgical Services Netra Rukshak: Rural Eye Services Wing Head, Eye Department Breach Candy Hospital and Research Centre Sea Side, 147 Shahid Bhagat Singh Road, Mumbai, India

Mody Kirit K

MD FRCS

Medical Director Salil Eye Clinic & Contact Lens Centre, 506 Om Chambers, 123 August Kranti Marg, Kemps Corner, Mumbai, Hon Professor Grant Medical College Hon Eye Surgeon GT General Hospital Conwest Jain Clinic Hospital Smt. Lilavati Hospital Mumbai, India

Murthy Gowri J

MD

Consultant Ophthalmic Surgeon Prabha Eye Clinic 504, 40th Cross, 8th Block Jayanagar, Bangalore, India

vii

MD

Cornea Fellowship (USA), Phacoemulsification, Excimer Laser, Cornea and Contact Lens Specialist New Delhi Centre for Sight A-23 Green Park, Aurobindo Marg New Delhi, India

Pradeep Venkatesh Pool Officer Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Shroff Noshir M

MD

Medical Director Shroff Eye Centre A-9 Kailash Colony New Delhi, India

Ranjan Dutta

MD

Shroff Eye Centre A-9, Kailash Colony New Delhi, India

Gurpreet Singh

DO

Shroff Eye Centre A-9, Kailash Colony New Delhi, India

Vajpayee Rasik B

MD

Professor Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Vishal Gupta

MD

Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India

Inderjit Singh Professor and Head Coffs Harbour Hospital 69 Albany Street, Coffs Harbour New South Wales 2450, Australia

Preface

Advances in the field of Cataract surgery and intraocular implantation over the last 50 years have been astonishing. Phacoemulsification, had a slow beginning, but in the last 5 years has exploded forwards. Improvements in technique are increasing at a rapid pace, as the advantages of small incision cataract surgery, the instant patient rehabilitation physical and visual are obvious. Nevertheless, the ultimate expression of minimal patient inconvenience and minimal delay in resumption of patient’s lifestyle is the legacy of Phacoemulsification It was in the winter of 1989 when one of us (KRM) performed our first cataract operation utilizing Phacoemulsification. From that moment onwards, we had no doubts that this was a winning combination and in future all cataract operations would be performed with this technique and with this technique only. The procedure has changed since then. It has evolved and improved significantly. The technique has been perfected. The technology has progressed. The quality of the surgery is now virtually unsurpassable, and most importantly, surgeons all over the world now trust and rely on the Phacoemulsification technique. Old concepts change, giving way to new ideas, as fresh advances in all fields of science and medicine forge ahead. Phacoemulsification surgery and its complications are no exception. We have tried to be highly selective in modifying old concepts and including not only those changes that have widespread acceptance but also have included newer developments which will make their mark in the new millennium. The visual needs of patients are dictated by their circumstances, which include age, occupation, leisure interests, and their independence. As an adviser to a patient, the ophthalmic surgeon must consider the individual requirements of the patient and balance these against the potential risks of surgical treatment. As a surgeon, his or her attitude is tempered by his or her experience, knowledge of the experiences of others and confidence in his or her own ability to achieve perfection of results that should shine as a beacon of excellence in the community. The primary intent of the book, The Art of Phacoemulsification is to provide an introduction to the subject of Phacoemulsification as well as the framework on which could be constructed the study of that discipline. Presentation of the material begins with the most fundamental aspects and builds up successive levels of knowledge.

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The purpose of this volume is to consider, in-depth, all aspects of Phacoemulsification. It is hoped that it will provide the ophthalmic surgeon who intends to commence Phacoemulsification surgery with the information necessary for effective and safe participation. For those who are already in this exciting field, this book should provide a useful source of reference. It is designed to consider both the problem and its solution. The solution has many variations but all should take into account the vulnerable tissues that are required to be protected during surgery. Every step of Phacoemulsification procedure is critical in determining the final surgical outcome. The surgery is a sequence of steps, each fundamentally important to the entire procedure. Thus while this treatise has designed to allow the readers to refine and enhance their surgical technique, it should reveal the latest advances in both the science and art of the modern technique of Phacoemulsification cataract surgery. The Art of Phacoemulsification has been conceptualized by some of the foremost cataract surgeons in the world. These contributing authors share their preferred techniques and ideas presenting the most advanced methods of surgical procedures, the newest equipment available, and their methods of managing the cataract patient. It will undoubtedly be apparent to many readers that some subjects have received a greater emphasis than others. These represent to some extent, our special interests and experiences. The major task of keeping abreast of the dynamic changes in Phacoemulsification surgery is nearly nondescribable. No single surgeon can speak authoritatively about every subject. Nor can every aspect of the subject be covered. This book covers a fair set of surgical methods and complications. Each chapter thus is an insight into the technique suitable for each surgeon and most importantly; the technique, which best suits that particular case. Each surgeon provides a detailed description directly from his or her experience of the more important Phacoemulsification techniques and his or her reaction to each new development. All contributors are aware that the production of a book having such a large volume of information, takes many months. Time and tide wait for none and certainly; the fast changing field of Phacoemulsification has new developments literally every day. The subject is developing rapidly, but it is our hope that the wealth of experience incorporated here will be valuable not only in the present time, but also for the future. This book is a multi-authored text and is, as such, abounds in differing literary styles. The editors have sought to provide a level of organizational conformity and scientific balance without sacrificing the originality and style of the individual authors. A distinctive feature of this book is the diversity of its many outstanding contributors. Probably the outstanding characteristic of this book is the editors’ ability to select critically important contributions to the management of cataract problems. These are analyzed and evaluated based on their vast experiences as ophthalmic surgeons and consultants.

P REFACE

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We would like to thank the contributing authors who are by their own right, considered the outstanding leaders in the field of Cataract surgery. This book would be non-existent without the devoted and tireless efforts of these physicians who contributed to this text while maintaining a rigorous daily practice. With promising laser techniques on the horizon, non-invasive Cataract surgery may soon be feasible. Many of these exciting developments are arriving so rapidly that even senior consultants in the field are often hard-pressed to keep up with the latest advances. What the future holds for us is difficult to portend, but one thing is certain, it will be exciting. Finally, the editors wish to take the liberty to express their deep appreciation to Jaypee Brothers Medical Publishers, India’s premier medical publication company, for their unflagging encouragement and tireless assistance in the production of The Art of Phacoemulsification. Mr Jitender P Vij, the Managing Director of Jaypee is truly a gem of a man, not only for his great faith that I would, one day, finally finish this epitome, but also for the general all-round editorial assistance given, the well laidout pages and the crisp photographs which have made it, truly, a world class book.

Keiki R Mehta John J Alpar

Contents

1. Commencing Phacoemulsification: The Basics .................................................. 1 Keiki R Mehta, Ranjit H Maniar

2. The Phacomachine ................................................................................................... 15 Mahipal S Sachdev, Pradeep Venkatesh

3. New Phacomachines Offer More Control ......................................................... 32 David E Allen

4. Cavitating Microbubbles Create Shock Waves that Emulsify Cataract ...................................................................................................... 45 Peter L Davis

5. Local Anesthesia ....................................................................................................... 51 KR Murthy

6. Ocular Anesthesia for Small-Incision Cataract Surgery ........................................................................................................ 58 Samuel Masket

7. The Limbal Incision ................................................................................................ 64 Shashi Kapoor

8. No Anesthesia Cataract Surgery .......................................................................... 76 Amar Agarwal, Athiya Agarwal, Sunita Agarwal

9. Clear Corneal Cataract Surgery ............................................................................ 86 Keiki R Mehta, Cyres K Mehta

10. Capsulorrhexis: A Beginner’s Guide .................................................................. 94 Shashi Kapoor

11. Capsulorrhexis: Principles and Advanced Techniques ................................103 Shrikant Kelkar

12. Hydrodissection and Hydrodelineation ........................................................... 112 Keiki R Mehta, Cyres K Mehta

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13. Phacoemulsification: The Quadrantic Cracking, Chopping and Stuffing Technique ................................................................................................. 118 Noshir M Shroff, Ranjan Dutta, Gurpreet Singh

14. Current Phacoemulsification Techniques ......................................................... 130 Richard Packard

15. Phaco Slice and Separate ..................................................................................... 154 Steve A Arshinoff

16. Cataract Extraction and Lens Implantation: The Implosion Technique .................................................................................... 161 Eric J Arnott

17. Phacoemulsification in Special Situations ...................................................... 170 Rasik B Vajpayee, Tanuj Dada

18. Zen in the Art of Phaco ...................................................................................... 177 Jonathan P Ellant

19. My Personal Technique of Vertical “Hubbing” Phacoemulsification ................................................................................................ 187 Keiki R Mehta

20. Innovative Nucleotomy Techniques .................................................................. 204 Vijay K Dada, Namrata Sharma, Tanuj Dada

21. Phacoemulsification in White Cataracts .......................................................... 214 Rasik B Vajpayee, Tanuj Dada, Vishal Gupta

22. Phacoemulsification in Difficult Cases ............................................................ 223 Inderjit Singh

23. Irrigation and Aspiration following Phacoemulsification .......................... 246 Keiki R Mehta, Cyres K Mehta

24. Foldable Intraocular Implants ............................................................................ 253 Vijay K Dada, Namrata Sharma, Tanuj Dada

25. History of Lens Implantation ............................................................................. 263 Eric J Arnott

26. Implantation Techniques of Acrylic Foldable Intraocular Lens and its Clinical Results ........................................................................................ 268 Tetsuro Oshika

27. The Mini-loop Plate and Accommodating Lenses ....................................... 288 J Stuart Cumming

28. Suprahard Cataracts: Their Evaluation and Management ......................... 299 Keiki R Mehta, Kirit K Mody

C ONTENTS

xv

29. Stretch Pupilloplasty for Small Pupil Management in Cataract Surgery ...................................................................................................... 314 Luther L Fry

30. Management of Glaucoma in Cataract Patients ...........................................322 Gowri J Murthy, KR Murthy

31. Phacoemulsification in the Previously Filtered Eye .................................... 329 Garry P Condon, Luis W Lu

32. Phacoemulsification in Patients with Significant Astigmatism ................ 344 Luis W Lu, Louis D Nichamin

33. Cataracts in Patients with Uveitis .....................................................................353 Enrique Chipont, Jorge L Alio

34. Corneal Endothelium and its Protection in Phacoemulsification ................................................................................................ 365 Keiki R Mehta, Cyres K Mehta

35. Phacoemulsification in the Presence of Pseudoexfoliation: Challenges and Options .......................................................................................381 I Howard Fine, Richard S Hoffman

36. Phacoemulsification in Severe Chronic Obstructive Pulmonary Disease ................................................................................................. 388 I Howard Fine, Richard S Hoffman

37. The Prevention of Complications and their Management in Phacoemulsification ................................................................................................ 393 Keiki R Mehta

38. Management of Posterior Chamber IOL Capture ........................................ 415 Durval M Carvalho, Durval M Carvalho Jr

39. IOL Scleral Fixation in Aphakic Eyes .............................................................422 Durval M Carvalho, Durval M Carvalho Jr

40. Phakonit and Laser Phakonit ............................................................................. 446 Amar Agarwal, Athiya Agarwal, Sunita Agarwal

41. Pharmacology of Intraocular Solutions and Drugs used in Phacoemulsification ................................................................................................ 453 Keiki R Mehta, TP Lahane

42. Triple Procedure with Phocoemulsification before Trephination ............ 462 Emilio Balestrazzi, Leopoldo Spadea, Luigi Mosca

43. Multiport Phaco Tip: A Safer and More Effective Training Device for Phacoemulsification ........................................................ 471 Keiki R Mehta

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44. Intraocular Lenses Dislocated into the Vitreous .......................................... 479 John J Alpar

45. Favit: A New Technique to Manage Dropped Nuclei ................................ 486 Amar Agarwal

46. Laser Phaco Cataract Surgery ............................................................................. 493 Sunita Agarwal, J Agarwal, T Agarwal

47. Endoscopy-Assisted Phacoemulsification ......................................................... 500 Claude S Leon, Joseph A Leon, Danielle Aron-Rosa

48. Phacoemulsification: The Eye Camp Way ...................................................... 507 Keiki R Mehta, Kirit K Mody, Ranjit H Maniar, Cyres K Mehta, Akhil Bharadwaj

Index ............................................................................................................................ 529

The Ar Artt of Phacoemulsification The primary intent of this book is to provide an introduction to the subject of Phacoemulsification. Presentation of the material begins with the most fundamental aspects and builds up successive levels of knowledge. Every step of Phacoemulsification procedure is critical in determining the final surgical outcome. The surgery is a sequence of steps, each fundamentally important to the entire procedure. This book has been prepared by some of the foremost cataract surgeons in the world. These contributing authors share their preferred techniques and ideas presenting the most advanced methods of surgical procedures, the newest equipment available, and their methods of managing the cataract patient. This is a uniquely up-to-date book which covers scientific principles and current clinical and research trends, with practical information on patient assessment, variable surgical techniques, clinical results and the identification, avoidance and the management of complications. Keiki R Mehta, one of India’s foremost cataract surgeons, commenced intraocular implants in India in 1972, and developed in 1975, for the first time in the world, a soft HEMA Intraocular implant. He initiated Phacoemulsification for cataract surgery in 1979 and is known as the “Father of Phacoemulsification in India“. An exceptional surgeon, he has operated live in workshops, teaching phaco all over India. Dr Mehta is a popular teacher in great demand at conferences and symposia and has written many scientific books and published scientific papers, both at national and international level. He has been awarded eight gold medals and innumerable oration awards from national / international bodies. Extremely innovative, he has been on the cutting edge of technology and has devised multiple new techniques and instruments. John J Alpar is an exceptionally skilled surgeon , edited an extremely popular book, which literally became in the 1990’s, a bible for implant surgeons, termed ” Fechner’s Intraocular Lenses”,. With Professor Fechner of Hanover, Germany, Dr Alpar produced a book, impressive by its well-organized structure, its wealth of information, its practicality and the superb technique of presentation. A prodigious speaker and author, Dr Alpar has delivered 178 lectures, published 158 scientific articles , 11 chapters, 4 books and attended over 320 meetings. Widely traveled, he is a life member of the All India, Mexican and Hungarian Ophthalmological Societies, the Indian and Canadian Implant Societies, and is member of the Medical Societies in Peru, Japan, France. Dr John Alpar is respected worldwide for the quality of his work, the scope of his knowledge, his sharp intellect and brilliance and his keen, incisive analysis of facts.

Contributors include • Alpar John J • Fine Howard I • Fry Luther L • Jonathan P Ellant • Luis Lu W • Masket Samuel • Allen David E • Arnott Eric J • Richard Packard • Durval Carvalho M • Durval Carvalho M Jr • Arshinoff Steve A • Davis Peter L • AronRosa Danielle • Joseph Leon A • Emilio Balestrazzi • Oshika Tetsuro • Alio Jorge L • Enrique Chipont • Agarwal Amar • Agarwal Athiya • Agarwal Jaiveer • Agarwal Sunita • Agarwal T • Col Akhil Bharadwaj • Dada Vijay K • Kapoor Shashi • Kelkar Shrikant • Lahane Tatyarao P • Maniar Ranjit H

ISBN 81-7179-790-3

Rs.

JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD B-3 EMCA House, 23/23B Ansari Road, Daryaganj Post Box 7193, New Delhi 110 002, India

Keiki R Mehta Ranjit H Maniar

Commencing Phacoemulsification: The Basics

1

INTRODUCTION Phacoemulsification is a superb technique, but to be able to conduct it comfortably and effectively all the appliances, solutions and even the personnel in the theatre need to be properly located and trained to respond to any situation which may arise. It is imperative that the surgeon understands the basic applications of each of the different requirements. For maximum efficiency and safety, proper location and arrangements, right from the operating table, the microscope, the surgeon’s chair, the instruments on the trolley, the placement of the staff nurse, the assistants, and even that of the wardboys, have to be carefully planned and worked out in advance. Phacoemulsification is an instrument-based surgery. It is also a high-pressure surgery, with periods of calm alternating with high tension. Moreover, as such there must be adequate space in the theatre so that effective and rapid movement when and if required can take place smoothly. Too compact a theatre is a sure prescription for disaster. THE OPERATING ROOM: REQUIREMENTS AND NECESSITIES The operating room—requirements and necessities of primary importance is a properly designed and functioning operating room or theatre (Fig. 1.1). There are many important points, which need to be considered. Some of them will be felt unnecessary, but the strength of any chain is dependent on the weakest link. Thus every link has to be given its importance and considered on its own merits.

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Lighting Lighting often does not get the importance it deserves. It is important that the theatre can be lighted up properly, but equally important can also be darkened adequately. It should be lighted sufficiently with shadowless theatre lamps of adequate power (minimum 50,000 Lux lamps). Though most of the surgery is done under the operating microscope, there are times when good peripherally focused lights are an advantage as for squint or oculoplasty surgery. Additional, movable goose-neck direct or fiberoptic side theatre lamps are a necessity with good illumination and are especially good for capsulorrhexis in hard opaque cataracts. In addition, in case the theatre is darkened, provision should be made for spot lighting of the instrument trolley, the phaco unit, life-support systems, anesthetic equipment, with a lighting device on a rheostat so that the intensity is adequate for the scrub and circulating nurse and the anesthetist to see the equipment clearly, but is not so bright as to blind the surgeon. Many surgeons need a spot of light focusing on the operating table in addition to the operating microscope lights. General illumination of the theater is also an important requirement. Though the powerful focused lights may be shut off, gentle illumination is needed in a theatre to allow for movement. Tube lights, ideally should never be used in the theatre as they are very distracting especially when the flicker increases as the tube gets a little older. In addition the flicker fusion frequency of the operating staff tend to be affected by the tube light especially when they are tired after a long session, increasing surgeon and staff irritability Darkening the theatre enhances the contrast under the operating microscope and is extremely useful when doing a capsulorrhexis especially in a hard cataract. When the main theatre is darkened, provision needs to be made to gently illuminate the floor so that personnel can still move around without tripping on objects. It is important that spot lighting should be kept off places where high reflectance stainless steel appliances and instruments are placed. This is to prevent extraneous glare from reflection from these shiny surfaces. The colors of the clothing worn by the operating room personnel should be soft and muted avoiding harsh colors. Pastel shades of blue, green or yellow are quite acceptable, however; red and ocher should be avoided Air-conditioning and Ventilation The ventilation of the room should be adequate and the air-conditioning sufficient to compensate for the number of personnel who are going to be in the room. The air-conditioning vents should be so arranged that they do not allow the air to be blown over the operating surfaces and at the same time keep the theatre cool. The ideal operating temperature would vary from surgeon to surgeon, however, a good comfortable temperature level in India is 70o C. The ideal air-conditioning would be one-way, taking in air from outside, filtering it, cooling it, and then expelling it out again after circulating through the operation theatre. Most theatres in India and in most of the smaller hospitals and nursing homes would seem to have window- mounted

COMMENCING PHACOEMULSIFICATION : T HE B ASICS

3

air-conditioning. The size and number should be adequate to provide good cooling with the air intake for fresh air always remaining open. It is very important that every evening following surgery the filters of the air-conditioner should be washed and soaked in a dilute solution of Cetavalon for half an hour prior to being re installed in the air-conditioner. The position of the units should be such that they do not blow over the sterile field, or blow directly onto the operating staff. Noise Level in the Theatre An operating theatre should be an oasis of calm. It is therefore important that the operating room should be located in a quiet area of the hospital or facility, and away from distracting sounds. It is essential that the windows be double-glazed (twin sheets of glass with an air-space between them) to keep the noise level down to a minimal level. It should be imperative that the operating staff learn from the beginning that unnecessary talk be kept to a minimum level and communications as far as possible should be by hand signs. This would guarantee that the surgeon, and the staff enjoy adequate peace and quiet to be able to concentrate on doing a good job. Background soft music should always be played in the operating theatre as it defuses tensions. The music should neither have a harsh beat nor irregular cadences. Electrical Power and Outlets The power points in the operating theatre should use high-quality reputable switches of an adequate output so that they are not overloaded and at the same time, good contacts are obtained between the plugs and the sockets. Often, even in so-called, Five Star facilities, it is seen that from a single outlet, using multipoint extensions, a number of lines are drawn. The wires then are left carelessly on the floor. All power points should be far away from the surgical field and preferably from a central hanging pod so that one cannot accidentally trip over the wires. In case it is required to trail a wire on the floor, it must be well protected with a masking tape so it is not accidentally pulled out in the dark. The power outlets should be rated at a sufficient level to comfortably run the medical equipment. Over loading of the points often leads to failure at a critical time during surgery. It is also imperative that fuses be provided for every media outlet in the theatre of the self-adjusting type which could be reset simply by pushing in a button rather than the older wire-looped fuses. Sensitive instruments like a phacoemulsification machine and life-support evaluation systems (cardiac monitor or oxygen saturation monitors should always be run through an on-line UPS (uninterrupted power supply). This permits the surgery to be completed even if the lights go off or the power supply fluctuates or even trips (Fig. 1.2). Power Generators In India, as with many developing countries, power outage is not uncommon. It is important when the theatre is planned that one should compensate for this problem.

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Though it would be nice to have automatic switch-over power systems where the load is taken temporarily on batteries and then automatically shifted to the generated supply, it is a very costly system which is rarely used. Instead small power generators are utilized, adequate to run the theatre lamps, general lighting and power the instruments, including the Phacoemulsifier and support systems. It is important that the wiring be so organized that all that needs to be done, at the time of a power failure, is to turn on the switch and start the generator. The load on the generator should never exceed 75 percent of its rated output to prevent overload and tripping. The generators, which are usually run off petrol, kerosene or diesel, all have a few common features. They are all noisy, smelly and temperamental. Hence they need to be placed in a room with good ventilation, and isolated so that the sound and smell does not reach in the hospital or theatre complex. They should be serviced regularly, and personnel trained to start and run the units. Scrubbing Facilities The scrubbing room should be separate and kept outside the theatre. There is a specific reason for this. When gloves are worn there is always glove powder scattered around which is then be circulated in the room leading to contamination. Not only does this choke up the filters of the air-conditioner, but leave a patina of dust all over the sterile surfaces of the room. Personnel in the Theatre The ideal theatre room composition should be a scrub nurse, who surgically assists the surgeon, and a circulating nurse, who remains unsterile. In my theatre, where I like to have a turnover of around 12 to 15 cases per day, preferably in a threehour period, I find it best to use two separate teams. The scrub nurse who surgically assists me in the surgery will, after the case is finished, wash the instruments, place them into the sterilizing box and then put it herself into the autoclave. The scrub nurse then washes up again, dons a fresh gown and gloves and commences preparing for the next case preparing the table and opening up the disposables which are handed to her by the circulating nurse. The unsterile circulating nurse will open the presterile disposables, remove the instruments from the sterilizer, and hand them across to the scrub nurse. The second scrub nurse, who has been assisting me with the second cases, finishes, moves out, and the totally prepared first scrub nurse is ready to commence the next case. This technique has a big advantage that the scrub nurse knows all about the instruments, where they are placed and their functional status. In addition it makes for far faster and more efficient application. Theatre Autoclave The autoclave should be a rapid action unit with flash sterilizing ability. A number of sterilizing systems are now available. Statim is a common one in usage (I use

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the Statim Cassette Autoclave, which has an 8-minute cycle, just perfect) and has preset operative timing levels, has adequate safety fail-safe built-in, and even has a small printout which confirms that the autoclaving cycle was complete and effective. The cassette system makes it very simple to insert and remove the instruments. Another good system is the Totawer and the Korean system which work in essentially identical manner. It is important to have a proper place to store the autoclaved instruments and theatre linen. The corridors and wall nooks are not for this purpose. It has to be in a well-ventilated room, far away from any traffic so that sterility is not compromised. The Operating Table The operating table has, as its primary requirement rock-solid stability even under deflecting forces, like inadvertent pressure at the head end, or accidental tail end pressure or lateral pressure. The standard operating table with the rotating axis in the middle is not suitable for ophthalmic surgery as the slightest pressure at either the head end of the table or the tail end of the table causes the entire platform to rock. When an operating microscope is being used, zero movement is permissible with any level of safety and efficiency. A very steady table is mandatory. Some of the operating tables are exceptional, like the Marquette system which is, however extremely costly. Alternately, more economical systems like the EyeTech table seem to work equally well and are sufficiently rigid for ophthalmic use. The table should be motorized permitting free movement both up and down in fine increments so that it could be fine tuned with the surgeon and the microscope in position. There should be the ability to tilt the head end of the patient a little up or down to compensate for those with a larger anterior/posterior diameter of the head, or when little children are being operated. It should wide enough to accommodate the patient, but narrow at the head end so that it does not impede the surgeon especially when temporal; surgery is being undertaken. It is also important that there should be adequate place under the table for the surgeon’s feet, the foot pedal console of the phacoemulsification unit, as well as for the foot pedal console of the operating microscope. Foot-mounted electrical controllers for an operating table should be avoided as the irrigating fluid, be it normal saline, Ringer lactate, or balanced salt solution (BSS) is bound to splash on the floor leading to a short circuit. The operating table should also have the ability to take a right sided arm rest where the arm can be positioned by the anesthesiologist for placing an IV cannula for any intravenous injection or sedation as may be needed the need for inserting a very uncomfortable arm support under the back of the patient (Fig.1.3). The mattress of the operating table should be at least 3 inches thick. The primitive 1 inch hard, unyielding, uncomfortable theatre mattress should be dispensed off with. Unlike general and orthopedic surgery where the patient is deeply sedated or even unconscious, the average ophthalmic patient is wide awake. With the advent of topical anesthesia, with the patient having to lie, totally without moving for

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long minutes at an end, the minimum which could be expected is a comfortable rubber mattress. The discerning and concerned surgeon should try sleeping on his or her own operating table to see its comfort level. There has always been discussion as to whether wrist support is required. Proponents of the wrist support system feel that it helps in stabilizing the wrist, and at the same time permits a little cavity or gully for collection of fluids rather than letting the fluid rundown the face. On the other hand, there are others who feel that it restricts the freedom of movement of the hand around the face and since usually the forehead is already being used to support the fingers the presence of a wrist rest is superfluous. It is basically a surgeon’s choice. I personally feel it interferes more with the surgery than helps, and though I have used it in many operating theatres, have never felt that it was really necessary. Personally I feel it restricts the free movement of the phaco handpiece. However, it is an individual choice. The Surgical Chair Phacoemulsification requires both hands and both feet to be utilized simultaneously. It stands to reason that the surgical chair is an important piece of surgical equipment. It gives the surgeon stability, supports his back, it gives a comfortable seating arrangement. It is important to remember that the feet have to be kept on the pedals for the full time of the surgery, and the surgical chair must be so designed that it prevents any pressure on his thighs. It is imperative that the chair be very comfortable, for the surgeon will need to sit on it for long hours every day if he is to complete his surgical list. Any discomfort, overtime, tends to get magnified, which affects, in the final score, the surgical competence. In the intracapsular days, most surgeons operated without any magnifying aids except for low-powered spectacle magnifiers or head-worn loupes, and operated standing. The advent of extracapsular cataract surgery changed the entire gambit. The necessity of visualizing the red glow meant the use of a coaxial operating microscope became mandatory. With the use of automated irrigation/aspiration units, both feet needed to be utilized. Thus the surgeon had no option except to sit and operate. Ideally the operating chair should have a minimum of five and preferably seven smoothly moving, nylon castors, to give total stability, with a lock on at least two of them, to immobilize the chair. The arm rest should be of adjustable height and properly padded and designed with a slight hollow so that during surgery the resting elbows should not slip off (with, as one may well expect, dire consequences). They should support the elbow, but at the same time, should neither restrict, nor interfere with, the surgeon’s movement. The chair should also fit easily under the operating table, with adequate space for the surgeon’s thighs. The area below the head rest should not be in contact with the chair or its armrests, neither should the base touch against the operating table. The height of the chair could be either electrically or hydraulically adjusted so that the appropriate height for each individual patient and the surgeon can be utilized. Finally, the chair must be grounded.

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Operating Microscope The microscope is perhaps the most important single piece of equipment in the theatre. Without an exceptional microscope, good phacoemulsification is difficult, if not impossible. The basic requirements are as follows: Excellent optics with clear vision at the edge of the optics There should be no blooming or distortion of the image and the lenses need to be color corrected. The latest microscopes (Zeiss) have apochromatic optics. Adequate depth of focus The entire lens should be visible from the front to the back without refocusing. This is very important since when doing phaco the traverse of the tip from the front to the back of the lens is almost 4 to 5 mm and it is important that excellent focus be available at all times. Perfect coaxial optics Are of prime importance if a good red glow is to be visualized. In modern extracapsular cataract extraction (ECCE) and, even more so, phacoemulsification, the surgeon literally operates against the background of the red glow. A good glow from one edge of the pupil to the other is thus a basic requirement. Good X-Y device The advantage is that the position of the microscope can be adjusted during surgery utilizing the foot controls without having to manually push a heavy microscope around. A good X-Y device also compensates for the little head movement which is to be expected during surgery. Automated zoom magnification It is not absolutely essential but is extremely useful as one can zoom in for a difficult situation ( doing rhexis in a hypermature cataract, or to see the edges of the capsule while doing posterior rhexis) and then zoom out with a reduced magnification for more effective surgery. Easily movable without damaging the unit Should be mounted on movable castors so that it could be positioned easily and locked in place in the operating theatre. Proper and stable optics delivery The arm connecting the microscope head to the supporting pillar should have adequate movement but at the same time should possess rock-solid stability. It should be possible to position the microscope head easily and then lock the arms. Tilt optics Not mandatory but makes a great deal of difference in comfort. The horizontal to vertical tilt arrangement (range of 90 degrees) is in the opinion of the author a really useful device as it makes the difference between operating comfortably and struggling and operating. It is particularly useful when operating on patients who cannot lie flat and who have to be literally operated in a 45-degree position. One can position the microscope to be parallel to the plane of the head and then simply tilt the optics to operate comfortably.

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Fig. 1.1: Layout of operation theatre with phaco on right

Fig. 1.2: Showing set-up with video, VCR, cardiac monitor, oxygen saturation monitor and cautery on right side of surgery

Preoperative Microscope Positioning It is imperative that the microscope be positioned accurately at the time of commencing surgery. Ideally the microscope should be on the right side of the patient, the same side at which the phacoemulsification unit is kept. The left side is reserved for

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Fig. 1.3: Taken from the foot end of the patient. Anesthetist on the surgeon’s right side and instrument table on the surgeon’s left side

Fig. 1.4: Showing the double tubing Surge Suppression System attached to the author ’s Alcon Legacy

permitting the patient to be shifted from the gurney or trolley to the table and the subsequent removal after surgery. The ideal place for keeping the instrument trolley is at patient’s left. The surgical assistant stands on the same side. The operating microscope camera should have its monitor placed at the surgeons right, set slightly

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Fig. 1.5: The balancing balls designed by Dr Tony Fernandez for softening eye

behind the surgeon so that the scrub nurse and the anesthetist can both follow the progress of the surgery, at the same time it will not distract the surgeon. An X-Y attachment is a very useful adjunct as it allows the stabilization of the optical axis to the patient’s eye during surgery without unnecessary coarse movements of the optical head. The X-Y device should be placed at its zero position prior commencing the surgery. Most microscopes have removable autoclavable plastic, metal or silicone caps for the microscope. Alternatively, cloth covers, which can be autoclaved, can be utilized. It is important that all the arrangements and positioning of the microscope be done prior to commencing the surgery. The luminosity of the microscope should be kept at the lowest level consistent with good vision. It is important to remember that the so-called ‘cold” fibreoptic light is not really cold but simply not too hot. A good heat shield must be fitted in the microscope especially if the microscope has a filament bulb. Keep the light intensity low until required. Prior commencing, the surgeon should place the focus at one-third position, i.e. if the traverse can be visually divided into three parts, it should be fitted in the upper third. This allows the surgeon to have more than adequate range during surgery. The surgeon should commence with the microscope focused at the limbus where the initial incision will be made. Placing the setting at the upper one-third position of the head traverse, enables the available traverse ( up-down movement) of the microscope to be utilized effectively. It is also important to adjust the microscope optics to the surgeon’s ametropia and his interpupillary distance if the microscope is used in a multi-user environment.

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To enable good coaxiality so as to obtain an excellent red glow the corneal plane must be exactly at right angles to the microscope tube. Be certain to position the eye perfectly prior commencing. Many microscopes come with a small round macular occluder which can be brought into position after the critical part of the surgery is over to diminish the quantum of light entering the macula. A simple alternate technique is to change the angle of the optics immediately after the cortical aspiration is over and to dim the light. Modern phaco surgery is now so fast that sometimes one wonders whether it is really required, however it is a good practice and should be followed. Footwear Use in the Theatre The use of footwear is very much dependent upon the surgeon. I personally prefer to use stocking feet rather than using slippers or shoes as I personally feels that it gives far better control. The use of thin-soled tennis shoes would perhaps work just as well. The thick-soled Nike and Adidas shoes though excellent in the sport field are not really useful as the fine control is lost. Using the X-Y control with stocking feet is a snap as the toes can easily encircle the knob. However, thin-soled shoes do seem to work well. The problem comes about in utilizing the X-Y control on the microscope. Stockinged feet are able to comfortably go around the tip of the X-Y knob permitting exquisite control. The important guidelines to observe are comfort. Be careful not to use loose floppy footwear like rubber slippers or cotton slippers, as they tend to slide over the footswitch area and can, in a critical moment, jam the footswitch and precipitate problems. The Patient in the Operating Theatre Positioning the Patient in the Theatre The patient’s head should be positioned in such a manner that the iris plane is parallel to the floor and perpendicular to the coaxial light of the microscope. In case the patient’s eyebrow is pronounced or the nose is pronounced, both of which would interfere with the surgery, one can easily shift to a full temporal approach. I personally prefer to enter at the 10 o’clock position in the right eye and the same in the left eye. The only time I change positions to a full temporal approach is when space is inadequate for a proper exposure. It is always very tempting, after scrubbing, to enter the operating room and wear the gloves from the instrument trolley, next to the patient. It is important to don the rubber gloves prior to entering the theatre, and as far away from the instruments trolley as possible. Whenever gloves are snapped on, talcum/glove powder, which is on the gloves, tends to be liberated and then falls as a fine patina all over the instruments and the eye. Prior to commencing surgery the surgeon should wipe his or her hands with a sterile dry towel, after putting on the gloves so as to remove the excess gloves powder. Washing is also acceptable but must then be in copious distilled water as otherwise it simply cakes the gloves, making matters worse. The dry towel scrub is the best to remove excess glove powder.

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Preparation of the Eye The area around the eye and the eye itself are washed with 10 ml of 50 percent diluted Betadine 5 percent ( povidone-iodine) solution. A cotton bud soaked in full strength Betadine solution is swept along the lashes to make sure that they are well cleaned. Subsequently the eye is flushed out with distilled water or with Ringer lactate to remove all the impurities. There is never any need to cut lashes. Draping the Eye The area around the eye is dried thoroughly with a sterile towel. A sterile self-adhesive plastic drape, either individually, or as a part of a complete drape, must now be placed over the eye. The method of placement is fairly simple. The eyelids are kept widely open either by the surgeon’s left hand or kept open by the surgical assistant using cotton buds. The sterile drape is positioned over the opened eye, the tip of the index finger is allowed to press the drape in between the opened area, gradually letting the drape stick onto the lashes and then onto the area around the eye. Using a blunt-tipped scissors, the plastic drape is tented and then incised down the middle being careful that the cornea is not accidentally touched. A soft wire speculum or a self-retaining speculum is then inserted in such a manner that the incised drape turns over the lashes, and then passes under the lids, held in place by the speculum, isolating them from the sterile field. Another big advantage of draping is that at no time is there any accidental touch at the time of insertion of the phacoemulsification probe or the implant in the eye. Following the application of the drapes, a second cloth drape can be put over the site. It has three functions: (i) it acts as an additional sterile barrier, (ii) cuts down on reflections, and (iii) acts as an absorbent media. Use of Lid Stitches In the days of intracapsular and later extracapsular cataract surgery, the use of lid sutures or superior rectus sutures was almost a routine. In the phaco era, lid stitches are used extremely rarely and are quite unnecessary. The only time any sutures are used is a superior rectus suture placed if the surgeon requires more exposure as when he or she wishes to do a combined glaucoma and cataract procedure. By eliminating the use of a superior rectus stitch, postoperative ptosis incidence is markedly reduced, it is infinitely less traumatic, eliminates the hematomas, which occasionally accompanied the placing of the stitch, and reduces postoperative inflammation. Since more often than not, topical anesthesia is the technique of choice, the eye is kept stable enough by the patient and the use of the superior rectus stitch is thus redundant. Suction Facilities To maintain a dry field during surgery is important. It is very difficult to operate with a pool of liquid reflecting back the microscope light. Rather than repeatedly

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swabbing the area dry, which leads to conjunctival irritation and interferes with the surgeon, the best is to keep a small suction available. A good option is the use of self-retaining speculum with aspiration ports attached to a small dental suction which gives suction in the range of 5 to 7 mm Hg. An alternate method is to utilize a drainage device like a sterile plastic bag which can be attached on to the side of the eye to hold the excess fluid as it drains out, or to use an absorbent wick drape which permits easy leakage. Which ever device is used, it is important to keep the floor dry. Dripping irrigating solution can be a source of great irritation to the surgeon when it falls on his or her feet, or wets his or her clothes. In addition the dripping liquids tends to cause the phaco foot switch to become slippery and may even jam in time thanks to the dried salt crusts. In addition, the saline is electrically conductive and is thus an electrical hazard. FURTHER READING 1. Mehta KR, Sathe SM, Karyekar SD: Computer Terminal Usage and Eye Fatigue, Xth Congress APAO. Soc Proc 2:946-48, 1985. 2. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS-First 50 cases. All India Ophthl Soc Proc 56-60, 1989. 3. Mehta KR: Progressive corneal endothelial decompensation—extended wear contact lenses with aphakia. All India Ophthl Soc Proc 109-14, 1989. 4. Mehta KR: Endocapsular phacoemulsification and posterior chamber IOL implantation. All India Ophthl Soc Proc 217-20, 1989. 5. Mehta KR: Post-cataract astigmatism: A comparison between phacoemulsification and ECCE procedure: cataract with and without intra-ocular implantation. All India Ophthl Soc Proc 226-29, 1989. 6. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in paediatric cataracts. All India Ophthl Soc Proc 207-10, 1995. 7. Mehta KR: The loop tri suction nonphaco technique of small incision cataract surgery. All India Ophthl Soc Proc 210-12, 1995. 8. Mehta KR: The clear corneal phacoemulsification with injectable silicone lenses. All India Ophthl Soc Proc 218-22, 1995. 9. Mehta KR: An Advanced but simple keratometer for control of postoperative astigmatism. All India Ophthl Soc Proc 122-23, 1990. 10. Mehta KR: Posterior chamber implantation. All India Ophthl Soc Proc 143-44, 1990. 11. Mehta KR: YAG laser damage to intraocular implants—an evaluation. All India Ophthl Soc Proc 14750, 1990. 12. Mehta KR: Phacoemulsification—is it the true III world answer for eye camps. All India Ophthl Soc Proc 301-303. 1990. 13. Mehta KR: An analysis of causative factor leading to eye strain caused by computer monitor screens. All India Ophthl Soc Proc 334-36, 1990. 14. Mehta KR: Single stitch elliptical funnel incision for cataract surgery. All India Ophthl Soc Proc 25354, 1991. 15. Mehta KR: Bifocal intraocular implants—a functional evaluation based on 425 cases. All India Ophthl Soc Proc 271-74, 1991. 16. Mehta KR: Phacoemulsification with flexible PC IOL—is it really a step forward. All India Ophthl Soc Proc 287-88, 1991. 17. Mehta KR: The new phaco cleave technique for hard cataracts. J Intraocular Implant and Refractive Society, India 1(1): 74-75, 1996. 18. Mehta KR, Sathe SN, Karyekar SD: The new soft intraocular lens implant. Am Intraocular Implant Society J4(4):200-05, 1978. 19. Mehta KR, Sathe SN, Karyekar SD: New soft posterior chamber implant, X Congress of the AsiaPacific Academy of Ophthalmology. New Delhi,1985. 20. Mehta KR: Clear corneal phaco with injectable silicone IOL proc. All India Ophthl Soc Proc (Mumbai) 1995.

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21. Mehta KR: Phaco with flexible IOL—is it a step forward. All India Ophthl Soc Proc (Bangalore) 1991. 22. Mehta KR: The tripod posterior chamber flexible acrylic implant —the answer to better stability. APIIA Conference, 1997. 23. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997. 24. Mehta KR: Newer techniques for eye camp safe phaco techniques. APIIA Conference, 1997. 25. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 26. Mehta KR: The New Multiport Phaco Tip for Safer, More Effective Phacoemulsification, with Virtually Zero Capsular Damage. Proc of SAARC Conference, Nepal, 1994.

Mahipal S Sachdev

The Phacoemulsifier

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INTRODUCTION It is very important than a thorough knowledge of the phacoemulsification machine is available to the operating surgeon. There are many machines available in the market, each with their own characteristics. However once the basics of the machine are understood, it becomes simple to analyze them, and having done so, understand how exactly they work. All machines fall into two basic categories, those utilizing a peristaltic pump and those using a Venturi pump. It is critical that every surgeon learns about the machine parameters and their individual effects, how they interrelate and in total how they affect the environment in which the surgery is performed. The Machine: Basic Features The phacoemulsification machine (Fig. 2.1) is essentially a system which generates ultrasound energy transmitted to the tip of the handpiece. The machine console only generates the electrical energy. The conversion

Fig. 2.1: The Laser Phacoemulsifier Machine (Alcon Legacy)

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of electrical energy into ultrasound is at the handpiece level. The body of the machine thus basically has controls which modulate every key requirements, be it diathermy, irrigation-aspiration control, ultrasound energy stability, or even the height of the irrigation bottle, etc. The fine-tuning is done by the foot switch which gives the surgeon more flexibility. Every phacoemulsifier has five basic functions; diathermy, irrigation, irrigationaspiration, ultrasonic fragmentation and vitrectomy. Each of these functions has a handpiece to match them. Irrigation Handpiece The irrigation handpiece is used when only irrigation is required. It is connected to an irrigating cystitome for anterior capsulotomy, or to an irrigating loop for hydrodissection. Many machines have the ability to preset controls so that when only irrigation is required, the foot switch functions purely as an on-off mechanism. Irrigation-Aspiration (I-A) Handpiece The infusion liquid is sent to the anterior chamber through the connected tubes. The basic function of the I-A handpiece is to aspirate liquid and cortical material through the aspiration port, at the same time infusing chamber-maintaining liquid into the anterior chamber. Essentially the irrigation-aspiration (I-A) handpiece, has a either single piece metal (stainless steel or titanium) irrigation-aspiration sleeve or has an aspiration sleeve with a silicone sleeve that fits snuggly around the aspirating tip. The I-A tip differs from the phaco tip in being smooth and rounded with a single aspiration port on the side of the tip and not at the end. The sleeve may be turned to orient the irrigation port in any direction. The irrigation ports in the silicone sleeve should be kept perpendicular to the metallic aspiration port as this helps direct the infusion fluid along the iris plane. This reduces iris flutter during the surgery. Typically the I-A handpiece has a rounded tip with the aspirating port at one side usually 0.75 mm to 1.5 mm away from the tip. The opening can be in a diameter of 0.2, 0.3, 0.4, or 0.5 mm. The overall diameter of the I-A handpiece usually varies from 2.5 to 3.0 mm depending on whether the aspiration sleeve is metal, or of silicone. The angulations of the I-A handpiece can be straight, 45° bent, or has a 90° bend. Most surgeons prefer to utilize the curved I-A tip. Recently Alcon in its Legacy phaco machine has taken out a tip which can be varied as desired termed a “steerable tip”. The commonly used I-A port is a 0.3 nun port. It has the safety feature that it will aspirate the cortex and not the capsule. It is however wise to keep on one’s table a 0.5 port so that at times when you wish to aspirate larger particles it is available. The larger port is also useful when doing a direct aspiration, as is often done in a congenital cataract. Irrigation/aspiration handpieces corne with metal or silicone sleeves, each having their own advantages.

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Metal Sleeves Metal sleeves allow a more regular inflow since they neither are compressed by the incision edges nor are they compressed if the tip is moved in a tunnel obliquely when oar-locking can obstruct the flow. Having smoother edges they are easier to introduce into the phaco tunnel. They also do not snag on the edges of the iris. Naturally being metal, they last much longer (Fig. 2.2).

Fig. 2.2: Irrigation/aspiration metal sleeved handpiece curved, and 90 degrees bent

Silicone Sleeves Silicone sleeves have greater flexibility and by molding themselves to the walls of the tunnel (basically, once a tunnel is opened, it is no longer a slit but elliptical in shape) give a better fit, thus diminishing the leakage from the chamber. This is important especially if the eye pressure is a bit high, chamber is shallow, or in children (Fig. 2.3).

Fig. 2.3: Silicone-sleeved bent for irrigation/aspiration bent

The Diathermy Handpiece In diathermy handpiece is a very essential adjunct and is ideal when a blood-free field is required typically in preparation of squared or smile (chexron) scleral or semiscleral incision.

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Diathermy handpieces can be coaxial (Erasertm) or of the forceps type. The coaxial type is excellent in preparing and having a bloodless scleral area. The forceps on the other hand can also be used for sealing the edges of the conjunctiva together (coaptation) at the end of the surgery. It is essential that the minimum quantum of diathermy be utilized. In most modern machines the control of the quantum of diathermy is linear, i.e. it is controlled by depressing the foot pedal. The maximum and minimum values can be preset on the console. Anterior Vitrectomy Handpiece The unit can be either of the guillotine type or of the rotating type with a triangular tip. In the earlier days most machines had the rotating vitrectomy tip, but it was soon recognized that the moment the unit got a little older it tended to entrap and tug on the vitreous and hence the guillotine vitrector has now become a standard in most machines. For anterior vitrectomy, the tip usually comes with a perfusion sleeve which can be removed if so desired. On the console, the essential values of flow rate, cut rate and vacuum can be set to suit individual requirements. Ultrasonic Handpiece Bimanual It has become customary for many surgeons to use separate handpieces for irrigation and aspiration. This helps immensely in cortical removal (Fig. 2.4).

Fig. 2.4: Bimanual hand pieces, separate for irrigation/aspiration

Phacoemulsification of a lens nucleus depends upon ultrasonic power which is the function of the acoustic vibrator that has been incorporated into the ultrasonic handpiece. Attached to this vibrator is a hollow titanium needle or the phaco tip. The acoustic energy produced along the ultrasonic handpiece is then transmitted onto the phaco tip (Fig. 2.5).

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Fig. 2.5: Phacoemulsification handpiece with four crystals (Alcon Legacy)

The acoustic vibrator is of two types: magnetostrictive or piezoelectric device. The acoustic vibrator converts electrical energy into mechanical energy under the influence of an electrical signal. The acoustic vibrator oscillates longitudinally at a frequency between 30,000 and 60,000 Hz. This imparts a linear motion to the ultrasonic tip. The stroke amplitude of the linear movement is 3.1000 of an inch and the acceleration 80,000 to 2,40,000 G. Magnetostrictive Handpiece Magnetostrictive handpiece was the first in use, and has now been phased out. It uses an electric current to induce a magnetic field which results in the linear movements of the ultrasonic tip. The electromagnetic field is generated by a coil of wires wrapped around the handpiece. Advantages and Disadvantages of Magnetostrictive Handpiece • • • • • • •

Can be autoclaved repeatedly with no risk to the handpiece Much sturdier. Does not break if dropped Can be repaired easily The handpiece is larger (almost the width of the base of a billiard cue) It is much heavier Needs to be water-cooled The greatest problem is that power delivery is inadequate and often at peak powers tends to be erratic, more so as the handpiece gets older.

Piezoelectric Handpiece Piezoelectric handpiece uses electric energy to reorient the piezoelectric crystal which in turn is translated into linear movement. The piezoelectric transducer requires a direct electrical contact to be made with the crystal.

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Advantages and Disadvantages of Piezoelectric Handpiece • Has a more efficient power delivery. With the use of multiple crystals the full range of delivery can be made very smooth even at very small increments. • It is air-cooled • Is very much lighter, almost featherweight as compared to the magnetostrictive handpieces • It is however very fragile and can break on being dropped • Costly to repair. Some handpieces may need to be calibrated every 1500 phaco procedures for optimal output. Phaco Tip The phaco tip can have various bevel angles ranging from 0° to 60° and comes in various shapes and sizes. The phaco tip is made of titanium and is hollow with the distal opening functioning as the aspiration port. The acoustic energy produced along the ultrasonic handpiece is then transmitted onto the phaco tip. The angle of the tips are for basically two reasons: a flat tip, like the 0° and 15° are excellent for holding but very poor for cutting; on the other hand to make a trench in a hard cataract the 60° tip is ideal, but because of its large surface area of the oblique opening, its holding power is poor. Tips may also be of various types, flared at the end (Cobra tip) or with the tip bent (Mackool tip) or with small ports, termed ABS port (Fig. 2.6). Entering into the anterior chamber is easy with Fig. 2.6: Peristaltic pump of the 60° tip and progressively harder with a 15° Legacy machine or a 0° tip. The commonly used tips are 30° and 45° phaco tips.

Alcon

Analyzing the Tips 0° Tip 15° Tip 30° Tip 45° Tip 60° Tip

Basically a flat, square cut tip with minimum cutting power but excellent holding capacity. Ideal for phaco chop techniques. Less cutting and more holding power. Suitable for improving follow ability. Balanced cutting and holding power. Suitable in most of the phaco procedures. Sharp cutting with good cutting ability and less holding power. Very sharp cutting edge with minimum holding power. Ideal for grooving hard cataracts.

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Tuning the Phaco Tip The phaco tip is screwed into the handpiece directly using a wrench. The handpiece is then tuned so as to synchronize the mechanical movement of each tip with the handpiece. Autotuning also allows the handpiece to maintain its frequency irrespective of change in the density of the medium. A loose or a heavily used needle will not tune. It is also customary to tune every time a needle is changed. Some of the newer machine (Sovereign Allergan) can retune the needle in few seconds. The irrigation fluid is made to flow through the two side ports on the silicone sleeve. The silicone hub threads the sleeve onto the outer casing of the handpiece. In some instruments (Alcon), an internal rigid sleeve has also been designed to separate the aspiration and the irrigation fluids. This is also supposed to reduce the bubble formation that is often encountered during the phaco procedure. Phaco Power Settings There is no predetermined “correct” power. Initially the manufacturer’s recommended settings are used. With experience, each surgeon “fine-tunes” his settings. Power variables are adjusted intraoperatively depending on • Density of nucleus where phaco tip is engaged • Amount of tip engaged • Linear velocity of the tip during emulsification. When the power is inadequate, the tip will fail to cut the nucleus, and tend the push excessively on the nucleus which lead to zonular stress and can be dangerous. When the power is too much, rather than holding the nucleus it will cause the nucleus to flyaway from the ultrasound tip, termed chatter. Too much power can also accidentally pierce the nucleus, making a hole in the capsule and leading to a dropped lens, a catastrophe, best avoided. Thus setting a safe power setting prior commencing is important. A safe “standard” setting is as under. The ultrasound power is set to 50 to 70 percent. If the lens is soft, it is decreased to about 30 percent and if it is hard, the power is increased to 80 percent or 90 percent. Power is reduced if the nucleus chatters. At this stage, the linear ultrasound mode is changed to pulse mode, which tends to hold the nucleus better against the tip and by giving a break between each pulse enables the fragments to corne to the tip easier. The third-generation machines, having four crystals per handpiece, have far better fragmentation control and rarely need the power to be turned up above 70 percent. It is best to consult each individual manufacturer regarding their safe “recommended” settings and only after experience is derived on that machine gradually change the values to suit ones individual style of phaco. Ultrasound is inaudible. The buzzing audible sound often mistaken for ultrasound, is simply the harmonic overtones of the handpiece and phaco tip.

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Phacoemulsification Terminology Phaco power Phaco power is the ability of the phaco handpiece to cut or emulsify a cataract. Phaco power is directly related to stroke length, frequency and efficiency of handpiece. Stroke length Stroke length is the distance by which the titanium phaco tip moves to and fro. It is the most important factor in deciding the phaco power. The stroke length can be altered by changing the phaco power setting of the machine. Frequency Frequency is the number of times the tip oscillates and is fixed for a particular phaco handpiece. It is measured in kHz. Preset levels Each surgeon sets his level which he does not wish to exceed during the surgery, both for minimum levels as well as maximum levels. This is done so that the safe levels are not exceeded inadvertently during the stress of surgery. Linear v/s panel In linear control, pressing the foot-pedal leads to gradual rise of the parameters from zero to preset maximum with a linear relation to the footpedal control. In panel mode, the parameter reaches the preset panel maximum on pressing the foot switch without any linear foot pedal control. Essentially it panel is simply on or with no variables in between, panel mode is normally utilized for diathermy, flow rate or for vitrectomy settings, never for power settings or aspiration settings on phacoemulsification. Constant v/s pulse phaco power In constant mode, power is delivered continuously and it can be linear or panel controlled. Pulse mode allows phaco power to be delivered at preset intervals which can be varied. The pulse mode gives relative intervals where there is absence of tIP movement. This improves the flow characteristics and helps in evacuating small nucleus particles towards the end of the surgery. The pulse mode is also relatively safer for the epinucleus because a more consistent and predictable cutting power will provide greater stability in the posterior chamber. Maximum phaco power Maximum phaco power is preset by the surgeon. It determines the maximum obtainable ultrasonic energy when the foot pedal is fully depressed. Actual phaco power Actual phaco power in a machine with a linear foot-pedal control is proportional to foot pedal position and denotes the power actually being delivered at a given time. Effective phaco time (EPT) Effective phaco time is the total phaco time at 100 percent phaco power. It can be less than the total foot-pedal time. EPT is very significant as less EPT indicates proportionately less energy delivered to the eye thereby reducing the side effects of phaco power. When one compares the energy used between different types of procedures, or even between different instruments, one has to compare the EPT which is a much more accurate index.

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How does phacoemulsificatlon work? There are various steps involved in the actual phacoemulsification process. • Mechanical contact of the tip with the lens • Acoustical wave transmitted through fluid in front of the tip • Cavitation At the cessation of the forward stroke, the tip has imparted forward momentum to the fluid and the lens particles in front of it. On the tip being retreated, the fluid cannot follow thereby creating a void in front of the tip. The void is collapsed by the implosion (cavitation) of the tip thereby creating additional shock waves. • There is an impact of fluid and lens particles being pushed forward in front of the tip. Considering the mechanics of phaco it is clear that there is attenuation of energy on phacoemulsifying within nuclear material. This reduces the deleterious effects on the corneal endothelium. Therefore, posterior chamber phaco helps to maintain the safety of the procedure by increasing the working distance from the endothelium. Further, if phaco power is used only when the tip is in the nucleus, the safety margin is significantly enhanced. The ultrasonic handle has three functions, namely, irrigation, aspiration and fragmentation. These can be operated separately or simultaneously. The dynamics of irrigation and aspiration are now considered in detail. Irrigation System In most phacomachines, irrigation during phacoemulsification is provided by gravity feed through the space between the titanium phaco tip and the sleeve. The amount of irrigation is determined by the bottle height relative to the patient’s eye, by the sleeve diameter, and most importantly by the loss of fluid from the eye. Stable anterior chamber dynamics: Irrigation = aspiration + leakage from the wound. Rigid sleeves may be preferred over flexible sleeves because the irrigation does not get compromised while manipulating the handpiece in the incision. The height of the irrigation bottle during phaco is usually placed between 65 cmand 75 cm above the eye level. The eye should be at the same level above the floor as the pump (cassette) of the phacoemulsifier. Aspiration System Aspiration is defined as the evacuation of fluid through a closed system. Two important concepts concerning aspiration are flow rate and vacuum level. Flow rate Flow rate is the quantity of the fluid pulled from the eye per minute through the instrument tip and irrigation tubing. Flow rate therefore helps in bringing the material towards the tip. Flow rate is measured in cc/min and is dependent on the level of vacuum created in the aspiration tubing by the aspiration pump

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and surface area of the port of aspirating tip. Flow rate determines the rate of rise of the aspiration vacuum when the aspiration port is occluded. Vacuum Vacuum level is the difference in pressure between atmospheric pressure and the pressure inside the aspiration tubing. This is a negative suction pressure that is created by the pump. Port vacuum (mm Hg/min) = the vacuum created (mm Hg) port area (mrn)2 The vacuum level created at the port therefore varies inversely with the diameter of the tip. The vacuum or negative suction force created helps in holding the material to the tip and its final aspiration. Aspiration Pumps Depending on the machine, three kinds of pumps are used to control aspiration and produce the negative suction pressure, i.e. the vacuum (Fig. 2.7). They are • Peristaltic pump • Venturi pump • Diaphragmatic pump.

Fig. 2.7: The peristaltic pump of the opticon P4000 machine

The peristaltic pump is also known as a “constant flow” pump while the Venturi and the diaphragmatic pumps are of the “constant vacuum” variety. Peristaltic Pump Peristaltic pump (Figs 2.8 and 9) was popularized by the heart-lung machine. In these pumps, a pressure differential is created by compression of the aspiration tubing in a rotatory motion. When the rotational speed is low, vacuum develops only when the aspiration port is occluded. On occlusion, vacuum builds up to preset

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Fig. 2.8: Full function display of the Alcon Legacy Machine

value in a stair-stepped pattern. By increasing the rotational speed, as in the newer generation machines, a linear build-up of vacuum occurs even without occlusion of the tip. It can thus be made to simulate a Venturi or a diaphragmatic pump. Advantages of a Peristaltic Pump • • • •

•

Fig. 2.9: Hand-held full function remote control of Alcon which controls the Alcon Legacy Machine

• •

Vacuum build-up occurs only on occlusion of the aspiration port. There is a large safety margin in this pump as it is slower in building up vacuum The peristaltic pump is a dedicated anterior segment system The peristaltic system is a more forgiving system as there is no inadvertent pull on the ocular structure since vacuum builds up only on occlusion The fluidics of the peristaltic pump are more controlled with little or no deflation of the anterior chamber on sudden removal of occlusion Vacuum level and flow rate may be controlled independent of each other Peristaltic pump allows both zero and high vacuum phaco.

Disadvantages of a Petlstaltlc Pump • The vacuum build-up is directly related to the density of occlusion which in turn would depend upon the bevel angle of the titanium tip and the tissue density • The vacuum build-up is in a stair-stepped pattern

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• Because of the stair-stepped pattern of the vacuum build-up, there could be more pulsations in the anterior chamber • True linear aspiration is not seen, however newer pumps do simulate a linear build-up of vacuum • One has to mechanically approach the nuclear or cortical matter to first achieve occlusion for vacuum to build up in order to aspirate the tissue. However, the rapid rotation mode has significantly improved the followability of the tissue, even in the peristaltic pump. Venturi Pump A Venturi pump uses compressed gas to create inverse pressure. Vacuum generated is related to gas flow which in turn is regulated by a valve (vacuum build-up occurs linearly in a consistent manner from zero to a preset value. The build-up is almost instantaneous on pressing the foot-pedal. Due to this there is an increased risk of iris trauma and posterior capsular rents which make these pumps unsafe, particularly so for beginners. Advantages of a Venturi Pump • There is a good follow ability of the tissue • The vacuum build-up is linear • There is a consistent increase in the vacuum from zero to the preset level on depressing the foot switch • Nuclear and cortical material can be attracted towards the probe on depressing the foot pedal. Disadvantages of a Venturi Pump • This pump has the least safety margin and is not forgiving to the surgeon • The rise time is too fast • There is an immediate rise in the vacuum on pressing the foot switch to position 3 without any linear foot pedal control • The incidence of iris chaffing and posterior capsular rents have been reported to be much higher with this pump as compared to’ the peristaltic pump • Venturi pump does not allow either zero to high . vacuum phaco. Diaphragm Pump A diaphragm pump uses a flexible membrane within a cassette to generate vacuum. Build up of vacuum is more linear and reaches the preset level even without occlusion. This makes it unsafe. However, lens material can be aspirated without having to mechanically approach it. Advantages of Diaphragm Pump • There is an improved linearity of vacuum build-up • The flow rate and aspiration are faster • Tissue can be pulled towards the center as vacuum builds up to preset even without occlusion

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• There is a greater control with the diaphragm pump during posterior segment surgery. DIsadvantages of a DIaphragm Pump • This being a faster pump it offers lesser safety margin • Foot pedal depression does not have a very good graded control over vacuum build-up • Rise of vacuum depends on the fluid in the chamber • Vacuum build-up reaches preset level even without occlusion. This leads to inadvertent pull on ocular tissue resulting in a higher complication rate • A Venturi is not a forgiving pump and has to be handled by newcomers with caution though in the hands of an expert it can give excellent results. Physics of Phaco: Certain Aspects Aspiration pressure It is modified depending on the stage of surgery and is inversely proportional to the diameter of the aspirating port. The ultrasonic tip has a port diameter of 1.00 to 1.20 mm with which the maximum vacuum achievable is 70 to 100 mm of Hg. However, in new machines (Alcon’s Legacy, and the Allergan Sovereign series, etc.) the vacuum can be raised to 500 mm of Hg in the phaco mode. The I-A tip has a diameter of 0.3 mm and the aspiration pressure may be increased to 500 mm of Hg. Rise Time and Pump Flow Rise time Rise time is a measure of how rapidly vacuum builds up once the aspiration port is occluded. Pump flow Pump flow is a measure of the rotational speed of the peristaltic pump head (which in turn determines flow rate and aspiration). This changes from machine to machine. RelationshIp of Illse TIme and Pump Flow As the pump flow increases, vacuum builds rapidly as the tip is occluded and therefore the rise time decreases. Pump flow is usually preset by the surgeon and is measured as a percentage. Normally 100 percent is equal to flow rate of 35 cc/minute. It is an overall measurement of fluid turnover in the eye. Pump flow determines rise time and event time. Vacuum Settings Maximum vacuum Determine the maximum obtainable vacuum when the aspiration port is fully occluded. Maximum vacuum is preset by the surgeon and is measured in mm of Hg. Typical settings are 65 to 75 mm Hg for phaco and 400+ mm Hg

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for irrigation aspiration. The speed at which this vacuum is achieved is determined by the pump flow setting and the bore of the aspirating tube. Actual vacuum It indicates pressure at the aspirating port at a given time. This depends on the maximum preset pump flow, degree of tip occlusion and position of the foot pedal when linear control is used. RelationshIp Between Pump Flow, Irrigation and Aspiration With an increase in the pump head rotational speed, the pump flow increases. Due to this, both aspiration rate and irrigation flow also increase. Relationship between pump flow, rise time and vacuum To reach a preset vacuum, as pump flow increases the rise time decreases, e.g. if pump flow is doubled the rise time gets halved. Fluidic Balance Fluidic balance is the balance between inflow of fluid into the eye and the outflow of fluid out of the eye, which helps in maintenance of the IOP. An adequate fluidic balance provides • Constant lOP • Stable anterior chamber • Protects corneal endothelium and posterior capsule. The amount of irrigation is determined by the bottle height relative to the patient’s eye, by the sleeve diameter, and, most importantly, by the loss of fluid from the eye. The following situations may exist: • Balanced anterior chamber dynamics: Irrigation = Aspiration + Leakage • Tight Wound (Irrigation decreases): Irrigation »Aspiration + Leakage A tight wound can limit irrigation if the space between the flexible sleeve and the phaco tip is compromised when manipulating the handpiece. This problem is not present with a rigid sleeve, although such a sleeve is not generally used because ‘contact with the rapidly vibrating phaco tip can cause serious overheating problems and tip damage if the sleeve is metallic. Excessive leakage between the rigid sleeve and the wound can also occur. Most surgeons have a shelved incision to reduce iris prolapse and create an efficient wound, although some fluid will, and should, always leak through the wound entering the anterior chamber. With an appropriate size keratome, i.e. 3.00 mm to 3.20 mm, proper irrigation is facilitated. Irrigation Bottle Height The irrigation bottle during phaco is usually placed between 65 em and 75 em above the eye. The eye should be at the same level above the floor as the pump (cassette) of the phacoemulsifier. It must be however understood that merely raising the bottle will not cure the problem of anterior chamber collapse caused by an

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excessively large wound, since irrigation and leakage are increased concomitantly by the increased force created by the higher bottle. Height of the Tubes Running from the Handpiece to the Machine Often forgotten and a sadly neglected fact that water always runs down hill. If the tubes are not supported but allowed to sag, when the phaco is turned off, the chamber will continue to empty which will lead to a chamber collapse. In addition it leads to air being sucked in the tubes which will lead to a compromised suction when the handpiece is used again. Always support the tubes at the same level as the patient’s eye. Thus a table which can be raised (A Mayo trolley) is an integral part of the set-up for good phaco. Enhancing Fluidics in a Phaco emulsification Machine The various ways to achieve good fluidics in a machine are 1. Narrower bore aspiration tubes Different size of irrigation tubing and aspiration tubing, irrigation being larger than aspiration. By making the aspiration tube with a narrower bore yet with a thicker wall decreases the compliance of the tubes and enhances response time with a more accurate aspiration pressure. It is the use of these high compliance tubing’S, (also called HiVac tubing’s) coupled with computerized controls which have made the new third-generation machines use higher and higher vacuum (and lower and lower ultrasound timings) with great safety. 2. By using software-driven pump systems where aspiration rate slows as the vacuum rises. Aspiration is zero at maximum vacuum, i.e. on total occlusion. As the occlusion clears aspiration rate slowly starts to rise from zero to maximum. A number of pumps at the time of release will actually reverse the pump a bit to make sure that the release is accurate. Foot Pedal The mode of operation in which the instrument is functioning on depressing the foot pedal in a linear manner is shown by the position indicator. Position 0 : Instrument turned on, no fluid flows, no ultrasonic vibration. Position 1 : Only irrigation solution is flowing. Position 2 : Irrigation and aspiration occur simultaneously. Position 3 : Irrigation, aspiration and fragmentation take place simultaneously. There is no position 2 or 3 in irrigation mode. Similarly there is no position 3 in I-A mode. A useful option in some machines is a foot pedal reflux control wherein fluid is pushed from the aspiration line to the eye in order to disengage tissue that has been inadvertently engaged in the tip. Programmability of foot switch In most of the machines these positions are prefixed. But in new advanced machines the positions are programmable, e.g. in Alcon Legacy, and the Allergan Sovereign.

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This provides more space between the position required and allows a better linear control. What Mode is the Machine Functioning? Every phacoemulsifier has various feedbacks to help the surgeon determine the mode in which the machine is presently working. The feedbacks could be tactile (foot) or auditory. Some machines have an electronic feedback. Tactile Feedback Increasing vibration in the handpiece may be indicative of increase in ultrasonic energy. Tactile feedback from the foot pedal depends on the machine. Some may have detents between the various positions while others may have uniform resistance, i.e. no detents. In few machines there is an increasing resistance with increasing depression of the foot pedal, while some machines may have vibrations between pedal positions. AudHoty Feedbacks Various auditory feedbacks are also preset in the phacoemulsifier. Auditory electronic sounds may be an additional feature of some machines, e.g. beeping is indicative of 1/A mode while a bell is indicative of occlusion at the tip. User modification may be possible with regard to type and intensity of the sound. Some machines will actually talk and tell you the mode you are in. And you can even choose your language. Essentials of a Good Phacoemulsifier • Good panel display (Fig. 2.10) with tactile controls parameters display. A continuous display showing all the variables at any time including the effective phaco time are essential. Simple fixed display machines are not really useful. • Linear and pulse mode should both be available in phaco mode. • Motorized infusion pole is preferable to change bottle height in order to alter rate of infusion. • Vacuum and flow rate should have separate controls. • Wet field cautery with a co-optation forceps should always be there with the cautery having the facility of both fixed and linear output. • A full function anterior vitrectomy unit should be in order to manage the complication of vitreous loss if it occurs. • Multifunction foot switch, i.e. it controls all the parameters with different foot switch positions is essential. A reflux mechanism should be present in the foot switch in order to disengage tissue when required. • Programmable foot switch is ideal. This facility available in the Allergen Sovereign and the Alcon Legacy series helps change the detents of the foot position 0, 1, 2 and 3. This enables the surgeon to have a greater play for different foot positions.

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• Full function remote is extremely valuable. It can be easily kept in the sterile area to facilitate change of parameters by the surgeon during the procedure. • Multiple programmability facility must be available. This allows individual surgeons to feed in their own parameters for surgeries on various grades of cataract as also for different stages of the surgery in a given case. • Facility for Reusable tubing’s and cassettes The machine should be cost-effective. In Indian circumstances, it is imperative that one be able to reuse the tubing’s, sleeves, etc.

Fig. 2.10: P4000 machine (Opticon)

The ophthalmologists need to carefully look at the various options available to them before purchasing a phacoemulsifier. Though several manufacturers are selling their products, one needs to remember that phaco surgery is significantly machine dependent. A good service back-up is therefore essential. It would always be prudent to take the opinion of a contemporary who is more experienced in the art of phaco surgery regarding which equipment to buy and the reasons for the same before taking a final decision. FURTHER READING 1. Arensten IT et al: Corneal opacification occurring after phacoemulsification and phaco fragmentation. Am J Ophthalmol 73: 794-804, 1977. 2. Barbell A: Health devices: Phacoemulsification systems. ECRI 18: 392, 1989. 3. Benolken RM, Emery JM, Landis OJ: Temperature profiles in the anterior chamber during phacoemulsification. Invest Ophthalmol 13: 71-74, 1974. 4. Binder P: Corneal endothelial damage associated with phacoemulsification. Am J Ophthalmol 82: 4854, 1976. 5. Ito K: Experimental studies on clinical and pathological changes of neighboring tissues of lens by ultrasonic vibrating tip for phacoemulsification. Japanica 74: 725, 1970. 6. Kelman CD: Physics of ultrasound in cataract removal. Int Ophthalmol Clin 9: 739-44, 1969. 7. Maloney WF, Maloney K: Two handed method. Video Journal Ophthalmology 3(4): 1987. 8. Pollack FM, Sugar A: The phacoemulsification procedure. II Corneal endothelial changes. Invest Ophthal 15: 458-69, 1976.

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David E Allen

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INTRODUCTION The art of cataract extraction has developed considerably over the past ten years, largely as a result of the increased sophistication of the machines the surgeon now uses to assist the process. This chapter is written with particular reference to four machines of which the author has experience. They are not the only machines to offer some of the features described, and the reader should be able, as a result of the knowledge gained from this chapter, to make appropriate enquiry to the manufacturers of other machines. THE MACHINE IN PRINCIPLE A generic phacoemulsification machine consists of two components: a pump which assists in the flow of fluid through the eye, and a probe which helps to reduce the crystalline lens to pieces of a size that can be removed by the pump. The pump actively controls the volume and rate of removal of some fluid from the eye (other fluid leaves the eye through incisional leakage). Inflow of fluid to the eye to replace that which leaves is passive, and is dependent on gravitational forces, modulated by the inflow resistance of the tubing and handpiece. If the anterior chamber is to be safely maintained, then the maximum potential inflow must exceed the maximum outflow of fluid. Modern machines offer very good control of the active removal of fluid. Phacoemulsification is achieved by either a magnetostrictive mechanism (the original type of phaco generator still used in some handpieces) or by the piezoelectric

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effect of certain types of crystals. Computer-controlled electrical circuits produce vibrations that are transmitted to a tungsten tip. The active mechanisms by which phaco needles work to break down the solid lens include • Ultrasonic effect of the high speed vibration of the tip • Cavitation effects • Particle and fluid pressure waves • Direct mechanical jack-hammer action. Modern phaco machines make use of sophisticated computer electronics to control the phaco-tip, and the tips themselves are being designed to enhance the “cutting” action, particularly using cavitation. SURGEON’S REQUIREMENTS DURING THE PROCEDURE Efficient Removal of Fluid and Particles from the Eye As described above, fluid egress from the eye is largely controlled by the machine, and is the most important factor in maintaining the correct balance. Modern pumps allow the rate of flow from the eye through the handpiece to be varied. Peristaltic pumps generate positive displacement of fluid along the handpiece tubing. Varying the pump speed has a direct effect on the rate of fluid displacement. Vacuumbased pumps (venturi or rotary vane) generate flow as a result of the pressure difference between the needle tip in the eye (at IOP) and the vacuum chamber in the machine. Varying the vacuum level in the cassette indirectly affects flow in these machines. A new type of pump (scroll pump) has characteristics that allows it to work in a way that emulates either of these modes and is currently available in the “Concentrix” module as an option in the Bausch and Lomb “Millennium“ machine. Varying the flow rate allows the surgeon to control the speed with which material is attracted to the tip. Low flow allows the surgeon to safely work close to sensitive structures such as iris or capsule (Fig. 3.1). A high flow rate causes material to be rapidly attracted to the tip, and once the tip is occluded, produces a rapid vacuum build-up. Flow of fluid also, as a secondary effect, tends to cool the phaco tip, both the flow along the lumen, but more importantly the compensatory inflow along the irrigation channel round the outside of the tip. Efficient Removal of Lens, Reducing the Amount of Phaco Energy Used This is achieved by using appropriate vacuum settings. In a flow-based system the maximum vacuum generated at the tip can be adjusted independently from the flow rate. In vacuum-based systems the vacuum in the machine vacuum chamber is the maximum vacuum that can be generated at the tip, as well as the factor controlling flow through the handpiece. Modern phaco machines allow the surgeon to select a vacuum setting that is much higher than was safe with older systems. Many modern systems can now safely use maximum vacuum settings between 300 and 500 mm Hg.

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Fig. 3.1: Low flow allows the surgeon to work safely close to sensitive structures such as iris and capsule

High-vacuum settings allow lens material to be removed through the tip with less phaco energy. High vacuum can cause nuclear material to be “molded” through the phaco tip without phaco energy, or allows low phaco power to be assisted by high vacuum in achieving the same effect. Whenever phaco power is applied to nuclear material at the tip the forward movement of the tip repels the material. Material held by a higher vacuum (and/or flow) onto the tip is less likely to be pushed away—increasing the tip’s effectiveness. The efficiency with which a tip functions to ”cut” lens material is another important factor. The tip and the handpiece (particularly the crystals or magnets it contains) tend to heat up during use, and this can have a significant impact on the functioning of the tip. The most efficient phaco machines have electronic circuits that frequently (or even “constantly”) monitor the performance of the tip and adjust the frequency of vibration to take account of this—“auto-tuning”. Some also adjust the voltage (power) applied to the tip to take account of the loading on the tip—taking account for example of the difference in effective weight of a tip if a large nuclear fragment is impaled on it. The shape of the tip has been the subject of developments in the past 10 years. The first really different tip was the “Cobra tip” (Fig. 3.2) produced by Surgical Design, and this has now been copied by several manufacturers. This tip has a conventional external diameter at the external opening, but 2 to 3 mm behind this the tip reduces significantly in diameter. The “shoulders” inside the tip increase the surface area moving back and forth, which has two effects. There is an increase in the amount of acoustic shock waves, but more importantly an increase in the cavitation effects of the tip (Figs 3.3A and B). Alcon subsequently developed the “Kelman tip”, which is bent and generates similar increased acoustic and cavitation

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Fig. 3.2: The Cobra tip

effects. Some manufacturers and surgeons are now reinventing the external shape of the tip to produce chisel, diamond, hexagonal and other external shapes. As a result there are now a group of needles from different manufacturers which are particularly powerful when used with medium or hard nuclei. A needle with a flared tip is also one with a reduced bore behind the tip. This has an indirect effect of reducing postocclusion surge because of increased resistance to outflow. Stable Intraocular Environment The modern cataract operation is characterized by superb control of the intraocular environment. This has resulted in a procedure that produces much less disruption

Figs 3.3A and B: Cavitation effect of Cobra tip

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to ocular physiology than older techniques. This is partly because of the reduced incision size, but also partly because of increased anterior chamber (AC) stability. AC stability is enhanced when fluid entry and egress to and from the eye are in balance. Modern machines allow this despite the trend, alluded to above, towards higher flow and/or vacuum settings. Modern peristaltic pumps produce a much smoother flow pattern than the versions used on early phaco machines. Modern microprocessor controls make the pump much more responsive to the surgeon’s demands (expressed through the foot pedal). Higher maximum vacuum settings can now be used as a result of this improved control as well as other improvements. When the phaco tip is occluded, vacuum in the tip and tubing equilibrates and approaches the maximum preset. There is then a pressure difference between the anterior chamber (usually at +30-40 mm Hg) and the lumen of the tubing or vacuum chamber (at the preset maximum, which may be as low as –400 mm Hg). When occlusion breaks, there is a rush of fluid from the AC into the tubing to equilibrate the pressures—postocclusion surge. Soft silicone tubing connecting the handpiece to the machine can tend to collapse when subjected to high vacuum during occlusion, and with the release of that vacuum can be subject to a rebound expansion. This re-expansion of tubing tends to increase the magnitude of postocclusion surge. Modern machines use a combination of different strategies to deal with postocclusion surge. The first machine to actively combat this problem and allow the use of high vacuums was the Surgical Design “Ocusystem“. This machine uses a combination of relatively rigid tubing and a pressure sensor in the aspiration line. When this sensor detects a rapid rise in pressure in the aspiration line (i.e. occlusion had broken), a pinch valve opens allowing a small volume of fluid from a secondary (higher) bottle to enter the aspiration line neutralizing the pressure differential. Other options range from the use of rigid tubing as well as an extremely low compliance pump (Bausch and Lomb ‘Millennium’), through microprocessor control that delays the uptake of pump rotation and sometimes transient reversal of pump (AMO ‘Sovereign’), to adjustments in the phaco tip that reduce the pressure difference (Alcon ‘ABS tips’). These and similar developments mean that modern machines can use much higher vacuum levels (up to 450 or 500 mm Hg during phaco), while still maintaining stability of the AC. This means the lens is removed more efficiently, there is less risk to the integrity of corneal endothelium and posterior capsule, and reduced breakdown of the blood-aqueous barrier (BAB) as a consequence of reduced AC pressure fluctuations. Reduced Flow of Fluid through the Eye Fluid outflow from the eye during phacoemulsification is not just through the aspiration port of the tip. There may be significant incisional leakage through the main incision or any side-port incisions. Traditionally, incisions have been made large relative to the tip, to avoid compression of the silicone irrigation (inflow) tubing. Compression of the inflow tubing has two effects: (i) maintenance of the

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anterior chamber is compromised by restricted inflow, and (ii) the cooling effect of fluid flowing around the vibrating needle is lost. Thermal damage of cornea/sclera then results. A rigid sleeve does not have this disadvantage, and the incision can be made as tight as possible – but there will always be some leakage. An alternative approach is to ensure that complete occlusion of a silicone sleeve cannot occur. This can be achieved by having some rigid elements within the soft, compressible outer shell (Fig. 3.2), or by grooving the external wall of the tip (Fig. 3.4). Fig. 3.4: Grooves on external wall of tip The volume of fluid flowing through the eye during surgery correlates with the risk of endophthalmitis and endothelial damage. It may also correlate with reduced inflammation and reduced BAB breakdown. Safe and efficient sealing of the incision around the probe along with the factors discussed above (higher vacuum, efficient tips) lead to a much reduced volume of fluid flowing through the eye. These all contribute to the improved outcomes of modern phaco procedures compared to earlier results. PRINCIPLES OF LENS REMOVAL AND MAKING BEST USE OF MACHINE PARAMETERS Original phaco techniques were dependent on the use of power to gradually “shave” the nucleus into a smaller and smaller piece. Modern lens removal strategies are based on mechanically breaking the lens into smaller fragments that can then be consumed. If the surgeon uses a technique such as “divide and conquer“ or “stop and chop”, the phaco probe is used to cut one or more grooves through the nucleus. These grooves are normally best cut as deeply as possible, close to the posterior capsule. Often (particularly when dealing with a soft nucleus) the surgeon will also wish to sculpt out close to the equator of the lens. When sculpting close to the posterior capsule, capsulorrhexis edge or iris (Fig. 3.1), the surgeon requires low flow settings on the phaco machine in order to minimize the chances of these structures being drawn into and being damaged by the phaco probe. As well as low flow during nucleus sculpting, the machine should be set with a low vacuum. This ensures that if the wrong structure is accidentally engaged, less damage will result and, for example, the capsule may not be torn if the preset vacuum is, say, 20 mm Hg. It is during the sculpting phase that the surgeon is most likely to require higher levels of phaco power, as the technique uses phaco power to cut through the lens material. The amount of power used should be titrated to the density of the lens. Once the lens has been broken into pieces (either by sculpting or by chopping/

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snapping), phaco power is much less important, and lower power levels can be used. Alongside this reduced emphasis on power however is the need for higher flow and higher vacuums when consuming the lens pieces. The higher vacuum holds pieces onto the tip and molds the pieces into the tip as described above. The flow rate determines the rise-time of the vacuum (the speed with which the preset maximum is reached) in a flow-based system, as well as determining the rate at which material is attracted to the unoccluded tip. Control of Power In this discussion I will use the conventional notation about foot pedal “positions” Fig. 3.5A). Position 1 refers to the range of pedal movement that allows simple irrigation. Position 2 refers to irrigation and aspiration, while position 3 adds phaco power. The first phaco machines had power output that was fixed at the control panel. All phaco machines currently in use allow the surgeon to control the power

Figs 3.5A and B: (A) Conventional foot pedal position,and (B) dual linear pedal

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in a continuous linear fashion in position 3 of the foot pedal. The surgeon can therefore titrate the power used according to the density of the nucleus and according to the particular maneuver in hand. One circumstance when a surgeon may choose panel control of power is when dealing with a hard nucleus. Under these circumstances it is easy for a surgeon to tend to try to physically push the tip into/through the nucleus, rather than allowing the ultrasonic power to achieve this. This inadequate use of power can put considerable strain on the zonules. Setting a fixed power level (say 50% or 70% for a very hard nucleus) ensures that maximum power is available to “cut” into the nucleus as soon as foot pedal position 3 is entered. Alternatively, the Bausch and Lomb “Millennium“ phaco machine has the ability to set a minimum as well as a maximum in its linear control of power. A surgeon therefore may choose linear control but power may start at say 35 percent and range up to 70 percent linearly. This retains the advantages of linear control (use of the minimum power level necessary) while reducing the chances of using totally inadequate power levels. While sculpting, the surgeon requires continuous power while the tip is advancing. For consumption of fragments, however, continuous power is not required, as the aim is to try to mold the fragment into a size and shape that will be aspirated. One of the earliest advances in the control of power, shortly after the concept of linear control, was pulsed phaco. The original rationale for this was the fact that applying phaco power to a fragment tends to push it away from the tip by direct hammer action of, and shock-waves from, the needle. After a short burst of phaco, the fluidics draw the fragment back into contact with the tip and re-establish occlusion in preparation for the next burst. Therefore the original drive was to make the power application more efficient. Now, however, the main reason for surgeons using pulsed power is to reduce the total amount of phaco energy used, by using short bursts to assist the vacuum in molding material into the tip. The second reason is that consumption of material is slowed, making it less likely that rapid consumption will lead to the attraction of unwanted material (such as capsule or iris) into the tip. Most implementations of pulse mode allow power to be varied as normal in foot pedal position 3. Some recent machines have an additional power variation known as burst mode. The machines can be set to deliver a single burst of power, at a fixed level, and for a set (but adjustable) duration, or can be made to deliver bursts at increasing frequency depending on the foot pedal traverse in position 3. With burst mode, power is delivered at a fixed level. Burst mode is said to be particularly helpful with techniques that employ embedding the phaco tip into the nucleus for some form of chopping/splitting. The use of a very short burst at fixed power prevents lateral spread of acoustic energy from the tip that can lead to the creation of a space around the tip preventing good occlusion. This type of phaco is said to lead to more efficient embedding into a tight-fitting space in the nucleus, and so a better seal is created, leading to better vacuum rise time, etc.

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Control of Flow All phaco machines currently in the market allow the surgeon to control the aspiration flow rate. Those surgeons using vacuum-based machines, however, (mainly Venturi) often do not realize that they have control. The principles were mentioned earlier in this chapter. Flow-based machines give the surgeon the ability to directly control the aspiration flow rate, and have a dial or electronic equivalent, that allows the direct setting of a flow rate in cc/min. With an unoccluded tip, flow in a vacuumbased system is generated by the pressure difference between the anterior chamber and the vacuum chamber in the machine. Therefore as the commanded vacuum in the cassette increases, the pressure gradient along the tubing increases, generating increased flow through the handpiece. Some machines have linear adjustment of flow rate (or vacuum) during traverse through foot pedal position 2. In addition to this feature all machines in current production have various memory settings which allow the surgeon to set different flow rates for different parts of the procedure, or different types of cataract. This ability to adjust flow rate (directly or indirectly) allows the surgeon to control the flow of material to the tip, or the vacuum rise time when the tip is occluded. The surgeon should always remember that all flow of fluid out of the eye must be balanced by an equal inflow if the anterior chamber is to remain stable and formed. In addition, the higher the outflow (and therefore inflow), the greater is the potential turbulence in the anterior chamber. This is important in the presence of an unstable capsule caused by either a break in the rhexis rim, or a rupture in the posterior capsule. Under these circumstances the surgeon should reduce the flow rate as well lowering the bottle height, to minimize stress on, and potential extension of, the torn capsule edge. Control of Vacuum Control of the maximum vacuum level has only recently become something that has featured in the thoughts of surgeons. This is because earlier generations of machines did not allow safe use of vacuum levels above 75 or 100 mm Hg. For the reasons rehearsed earlier in the chapter, higher vacuum levels are now safely used in some modern machines. The vacuum set on a flow-based machine is the maximum vacuum the machine is allowed to generate once the tip is occluded. In unoccluded mode, the pump generates flow through the tip. With an occluded tip, the pump continues to turn and generates a vacuum that rises towards the preset maximum. Once that maximum has been reached the pump stops and/or some venting into the aspiration line is allowed so as to maintain that vacuum level. Once the occlusion breaks and the vacuum reduces, the pump begins to turn again. In a vacuum-based machine, the set vacuum is that which is produced constantly in the vacuum chamber, and this indirectly causes flow until occlusion, and then, as in the flow-based system, the vacuum within the tubing and handpiece rises to that same level.

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However, there is more to vacuum control than just altering the maximum allowable vacuum. The rate at which that vacuum is actually achieved at the tip can be varied. This can be of use to the surgeon who may wish, for example, to have a slow “rise-time” of the vacuum, allowing time to correct any mistakes, rather than allowing a high vacuum to be rapidly reached before any error (such as engagement of capsule) can be corrected. In a vacuum-based system (e.g. Venturi) some form of restriction or limiter can be placed which effectively allows leakage of some of the vacuum as it rises towards the maximum. In a flow-based system the flow rate determines the rate at which the vacuum limit is reached. For example, once occlusion occurs, a given set vacuum is reached in half the time if the flow is set at 20 cc/min compared to the time taken at 10 cc/min. Thus a simple system can easily be adjusted to give the surgeon a vacuum rise-time he or she desires, at the expense of independent control of the flow rate. The Surgical Design Ocusystem was the first machine to offer the surgeon the opportunity of adjusting the rise-time while keeping the basic flow rate independent. For consuming nuclear quadrants, for example, the basic flow rate could be set at 25 cc/min, with a maximum vacuum of 350 mm Hg. The surgeon can, however, set a threshold vacuum (say 100 mm Hg) and when the vacuum reaches this level, a different flow rate is used. The postthreshold flow rate could be much lower— say 15 cc/min—if the surgeon feels there are risks with a rapid rise to higher levels (Fig. 3.6). Alternatively the post threshold rate could be even higher, if the surgeon is happy that by the time 100 mm is reached the chances of the wrong material being engaged has disappeared. Several machines now allow the surgeon to program this type of change in the rate at which the vacuum limit is reached. Sophisticated Foot Pedals As in the earlier section I will use the conventional notation about “positions“. Position 1 refers to the range of pedal movement that allows simple irrigation. Position 2 refers to irrigation and aspiration, and position 3 adds phaco power.

Fig. 3.6: Adjustment of vacuum rise time

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Fig. 3.7: Multifunciton foot switch

Foot pedals are no longer simple car accelerator-type pedals. Many machines now offer the opportunity to adjust the proportion of the total range of movement that is used for the three different “positions”, and save these in memory as part of the settings for a particular surgeon. All pedals have had some form of additional toggle switch (usually to the side) that switches on the reflux function. Now, however, it is common to offer even more toggle or rocker switches (Fig. 3.7). These can be used for activating the in-built diathermy on many machines, or for switching to different memory settings or “modes“. Some pedals can be set to activate an “emergency”change (for example rapid lowering of the inflow bottle height in the event of a posterior capsule rupture). While many see the proliferation of switches and rockers on newer foot pedals as a yet another complicating factor, they do undoubtedly offer the surgeon a greater degree of control and independence from support staff if that is desired. They do not have to be used if not desired! Major innovation in foot pedal design leading to even greater control over the procedure has been the introduction of a simultaneous dual linear foot pedal by Bausch and Lomb. This pedal allows the surgeon (again only if desired) to have linear control in position 2 while simultaneously having linear control of position 3. Standard pedals only have travel in one plane (pitch). The dual linear pedal also has the ability to rotate sideways (yaw). The surgeon can select whether ultrasound or flow/vacuum is the function controlled by yaw. If ultrasound is chosen for yaw, then this means that position 2 can be used to linearly control flow rate (say between 15 cc/min and 35 cc/min). At any point in the travel (i.e. at any flow rate) the surgeon can then add yaw and begin phaco (Figs 3.5B and 3.8). The phaco is also linearly controlled in yaw, and so at any flow rate there is also a range of phaco—

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Figs 3.8A and B: Yaw movement of pedal

say ranging from 0 to 30 percent. In addition to the added control this gives it also allows a greater range of pedal travel in position 2 (i.e. the whole range normally allocated to two and three are available in position 2). It is clear that by using this dual linear function there is a much reduced need for multiple preset modes for different types of nucleus or for different stages in the procedure. The surgeon can continuously adjust all the parameters in real time in response to changes in the characteristics of the lens being dealt with. Sophisticated Microprocessors The single most important factor in the development of the sophisticated equipment now available to the cataract surgeon has been the development of microprocessor control of the functions of the machine. Initially electronics allowed control over the power functions of the handpiece—pulse mode and “auto-tuning” being significant developments. More recently the processors have enabled sophisticated ways of enabling postocclusion surge to be controlled and minimized. The surgical design ocusystem was the first machine to introduce active ways of controlling postocclusion surge. This machine has a pressure (vacuum) sensor in the aspiration line. When it detects a significant and rapid drop in vacuum (as when occlusion breaks) fluid is immediately bled into the aspiration line, and this temporarily increases the pressure in the aspiration line, neutralizing and temporarily reversing the postocclusion surge. Later machines have employed a variety of methods to try to reduce postocclusion surge—some of which also employ sensitive pressure sensing devices and rapid electronic responses. The ability to program an adjustable rise time has already been mentioned. The AMO “Diplomax” and more recently “Sovereign” machines have made particular use of sophisticated microprocessors to enable their “occlusion mode phaco”. The

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basic concept here is that the surgeon may wish to use one set of phaco parameters while the tip is unoccluded (e.g. continuous phaco at a relatively low flow while sculpting). Once the tip is occluded (which the computer detects by rapid rise in vacuum level) the surgeon may want different parameters to consume a nuclear fragment (e.g. pulse phaco, at lower power, but at a high flow). Exactly how the various parameters change, and at what threshold vacuum limit this occurs is set according to the surgeon’s preferences, and stored in that surgeon’s individual settings file within the computer. Allusion has already been made in earlier sections of this chapter to the ability of the modern computers that control the generation of the currents that power the phaco probe itself. Control circuits within the computer continuously monitor the working of the crystals or magnet stacks in the handpiece and fine tune the frequency and power with which the needle is driven. Ability to adjust the foot pedal settings, range of travel in different modes, assignment of different functions to certain switches are particularly well developed in the unique dual linear foot pedal of the Bausch and Lamb “Millennium“ machine, which has three additional switches. One of these additional controls is a rocker switch to which the surgeon can assign various functions. For example it can be set to increase or decrease flow rate, vacuum limit, bottle height, etc. or be set to move backwards and forwards between program modes. Some surgeons are intimidated by the added sophistication of the latest generation of phaco machines. However they do offer user the ability to control much of the procedure in a way which was not possible with earlier simpler machines, yet they can be used in a “simple” way if that is the surgeon’s wish. Notwithstanding these reservations, the ability to take more control is welcomed by many.

Peter L Davis

Cavitating Microbubbles Create Shock Waves that Emulsify Cataract

4

INTRODUCTION Our ophthalmic literature has frequently presented inaccurate ideas concerning the basic physics of the energy source that emulsifies cataract. Included among them are the following • Cataracts are emulsified by phaco needles moving back and forth at ultrasonic speed, jack hammering and cutting lens nuclei into an emulsate. • A 45-degree angle phaco needle emulsifies hard lens nuclei more readily because a sharper tip cuts best into the nucleus. The above statements have been repeated many times since the early days of phaco. A senior executive of a pioneering manufacturer of phacoemulsification equipment related to me told that his company did not wish to confuse eye surgeons with information about ultrasonic energy. Therefore, the marketing section of his company decided that it would be best for salesmen to inform surgeons the phaco needle was “cutting” thus making the new phaco method a simple extension of scalpel surgery. The knowledge that ultrasonically activated phaco needles are creating massive shock waves the same as those that have been used to scale teeth and clean surgical instruments is often met with skepticism. This chapter reviews library and basic research that shows the shock waves energy that emulsifies cataract are generated by imploding microbubbles that form and collapse in fluid when the titanium needle is ultrasonically activated. History The basic physics study of the massive energy created by imploding bubbles started when the British Royal Navy began using steam turbine engines in the 1890s. These

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Fig. 4.1: Charles Parsons’ ship powered by a steam turbine engine

rotary engines had been engineered by Charles Parsons. He fabricated an engine and installed it in a small ship that he then demonstrated to the British Admiralty (Fig. 4.1). These new engines doubled propeller speed but to the consternation of the Navy the torpedo boat “Daring” that was first equipped with the new engines fractured its propellers. Lord Raleigh1 led the research that revealed the rapid propeller revolutions were hydrodynamically creating bubbles that imploded under water generating massive shock waves that destroyed the ship’s propellers. Research has since led us to the current situation when imploding shock waves are generated hydrodynamically, by whistles and by ultrasonic transducers that convert electrical to ultrasonic energy. KS Suslick2 has published a review of the basics of ultrasound and its applications. In the introduction to his text he states the use of ultrasound in industry and clinical medicine is common place but “there had been almost a complete lack of review material on the underlying principles from which such effects originate.” Reviewing Suslick’s 1988 multiauthor book and his article in Scientific American3 and going through the physics literature leads one to the conclusion that our phaco needles are not oscillating chisels.4 Basics of Phaco Transducers A transducer is a device that converts one energy form to another (Fig. 4.2). Handheld phaco transducers are converting electrical energy to ultrasonic (beyond 16,000 cycles/sec) acoustic waves. In the past, vibrating metal wafers were used in magnetostrictive devices notorious for generating and releasing heat that caused corneal thermal injury. Modern designs use piezo (Greek—to press) ceramic crystals to make the conversion. The piezo designs initially incorporated two crystals that were less durable than the magnetostrictive designs but were more efficient and generated less heat. In recent times, the transducers are manufactured with four crystals that makes them even more efficient (Figs 4.3 and 4.4).

CAVITATING M ICROBUBBLES CREATE SHOCK WAVES

THAT

EMULSIFY CATARACT

47

Fig. 4.2: A transducer converts one form of energy to another

Fig. 4.3: Piezoelectric transducers have replaced magnetostrictive designs

Cavitation (Transient) Eye surgeons dislike the gas bubbles that are released during phaco procedures to collect inside the corneal dome making it difficult to view the cataract. These annoying bubbles are air that was dissolved in the balanced salt solution (BSS) and was released from the BSS by ultrasonic wave activity in the eye (degassing fluids with ultrasound has been used in industry for decades).2 Unfortunately, these air-bubbles have been labeled “cavitation bubbles”. In contrast, ultrasound scientists discuss micron-sized bubbles formed by transient cavitation which is the formation of tiny invisible gas bubbles that implode creating energy at the end of acoustic horns in fluid (in ophthalmology—at the end of phaco needles) (Fig. 4.5). Ultrasonic waves released in fluid cause 100 to 150 micron size bubbles to form and then implode within a few acoustic cycles (current phaco transducers are vibrating at 27 to 55 kilohertz). The energy released by this microbubble implosion is in the form of shock and fluid waves. These activities are listed in Table 4.1.

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Fig. 4.4: Drawing of both piezoelectric and magnetostrictive design transducers

Fig. 4.5: Svensson’s photo of microbubbles at the end of phaco needles

This energy has been used for many industrial purposes including the cleaning of surgical instruments and contact lenses (the tiny flame at 1500 degree C that forms as the microbubbles implode is too small to raise the temperature of the fluid).3 Activity Around Phaco Needles Research done on phaco needles in vitro has demonstrated the same activity as has been shown in physics laboratories. The first papers using photography to demonstrate the microbubbles and flame were presented in 1991 at the American Table 4.1: Activities of imploding microbubbles (transient cavitation) 1. 2. 3. 4.

Shock waves of 500 atmospheres (enormous force) Fluid waves of 400 km/h A flame at 1500 degree C within the microbubble Radical ions

CAVITATING M ICROBUBBLES CREATE SHOCK WAVES

THAT

EMULSIFY CATARACT

49

Society of Cataract and Refractive Surgery (ASCRS) Meeting. Table 4.2 outlines the initial presentations of re-phaco needle shock wave physics. Table 4.2: Outline of two presentations at ASCRS 1991 showing evidence of transient cavitation with phaco needles Author

Method

Findings

1.

Svensson B

High-speed photography

Microbubbles forming and imploding on the rim of phaco needles (Fig. 4.5)

2.

Tsubota K

Heat-sensitive photography

Demonstrated flame in imploding bubbles at end of phaco needle

In more recent times, the demonstration of shock waves in fluid that have a different index of refraction (Schlieren activity) has been shown by optical and video recording (Fig. 4.6). Table 4.3 summarizes this research. Table 4.3: Documentation of Schlieren waves at the end of phaco needles 1.

Obermaier M

ASCRS, 1996

Demonstrated shock waves in vitro and in cadaver eyes (Fig. 4.6)

2.

Fishkind W

ASCRS, 1997

Video recording of shock waves in vitro

Fig. 4.6: Photo from Fishkind’s video recording of shock waves anterior to a 45-degree phaco needle

In recent years, phaco needles have had their ends enlarged or recessed to increase their surface area and allow the formation of more microbubbles that implode and release more shock wave energy (Fig. 4.7). I demonstrate this idea with an illustration prepared in 1991. Phaco surgeons often notice cataract tissue breakdown anterior to their phaco needles without the tip touching the cataract. This is because the shock waves are

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Fig. 4.7: A 0.4-mm phaco needle may have more microbubble formation

focused in front of the phaco needle as shown by Schlieren imaging. The presentation that phaco needles are simply vibrating chisels was a convenient way to market phaco technique when it was introduced. However, a reading of the basics of ultrasonic energy and more recent ophthalmic in vitro and cadaver eye studies outlined in this chapter, reveals the forces that emulsify cataract are massive shock waves formed at the end of phaco needles by imploding microbubbles. REFERENCES 1. 2. 3. 4.

Lord Raleigh: Phil Mag Serv 6:34-94, 1917. Suslick KS (Ed): Ultrasound: It’s Chemical, Physical and Biologic Effects VCH Pub Inc: New York, 1988. Suslick KS: The chemical effects of ultrasound. Scientific American 80-86, 1989. Davis PL: Phaco transducers, basic principles and corneal thermal injury. Eur J Implant Ref Surg 5: 109-12, 1993.

KR Murthy

Local Anesthesia

5

INTRODUCTION Surgical procedures in ophthalmology are usually performed under local anesthesia. General anesthesia is employed when the procedure is expected to be time consuming or if the patient cooperation is not possible due to young age, mental status or extreme apprehension. Even among regional blocks, there has been a change, towards topical anesthesia, as the technique of surgery has been constantly altered. Knowledge of the principles of mechanism of drug action, as well as the administration techniques, recognition of complications, and their management, is essential for the success of the surgical procedure. Mechanism of Action Local anesthetics must be, water soluble as well as lipid soluble in order to traverse the nerve membrane and bind with the phospholipid membrane that surrounds the inner openings of sodium channels. This impedes the access of sodium, to the axons and results in a reversible blockage of the nerve.1 The pH of the solution has an effect, on the onset, and spread of the anesthetic effect.2 Buffered solutions are less painful during administration.3 The duration of the effect depends, on the length of time, the agent is bound to the nerve membrane. The anesthetic drug and its concentration, and its rate of removal have an effect on the duration of action. It is to be remembered that these agents can be, readily absorbed through mucous membranes, and can cause toxic reactions.4 Hence, a surface anesthetic should never be injected. Cardiorespiratory resuscitation facilities should always be ready at hand. The body can metabolize the drug when toxic reaction

THE ART

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Table 5.1: Local anesthetic agents (topical) Agent

Trade Name

Concentration (percentage)

Benoxinate HCl (Combined with fluorescein sodium 0.25%) Cocaine HCl Proparacaine HCl

Fluress

0.4

Ak-taine Alcaine Ophthaine Ophthetic Anacel Pontocaine

1-4 0.5 0.5 0.5 0.5 0.5 0.5

Tetracaine HCl Onset within 1 minute Duration of action 10 to 20 minutes

(Physician’s Desk Reference for Ophthalmology Oradell, NJ, Medical Economics, 1991)

occurs, but resuscitative measures should be, at hand to maintain the ventilation and circulation till the drug is metabolized.5 Action of the local anesthetic can be enhanced by the addition of epinephrine 1:200,000 in addition it also provides vasoconstriction and reduces bleeding. Caution should be exercised when the patient has systemic hypertension and cardiovascular disease or thyrotoxicosis.6 Addition of hyaluronidase, which depolymerizes hyaluronic acid, results in quicker diffusion of the agent. Mechanical pressure is needed to spread the agent through the tissues effectively.7 Local Anesthetic Agents Topical (Table 5.1) Before starting surgical procedure under local anesthesia one should ensure that an intravenous line is started and emergency drugs are at hand. The patient should have a cardiac monitor and also his or her oxygen and carbon dioxide levels should be monitored. Facilities for oxygen administration and intubation should also be available and it is preferable if an anesthetist is available to manage an emergency or to give additional sedation if the patient is in need of it. Injectable See Table 5.2. TECHNIQUES

OF

LOCAL

ANESTHETIC

INJECTIONS

Orbicularis or facial block to paralyze the orbicularis muscle can be achieved by blocking the trunk of the facial nerve at stylomastoid foramen, (Nadbath block) or at the neck of the mandible (Obrien’s technique) in front of the tragus or by injecting at the orbital margin (van lint technique,/Atkinson block). When the peribulbar block with hyaluronidase is administered there is enough diffusion of the agent to block the orbicularis also and this negates a separate orbicularis block. When the trunk of the nerve is being blocked sometimes there could be

L OCAL A NESTHESIA

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Table 5.2: Local anesthetic agents (injectable) Agent (Trade name)

Chemical Class

Concentration (percentage)

Maximum Dose (mg)

Relative Potency

Onset of Action (min)

Duration of Action

Procaine (Novacaine)

Ester

1-4

500

1

7-8

30-45 min

Choloroprocaine (Nesacaine)

Ester

1-3

800

1

6-12

60 min

Mepivacaine (Carbocaine)

Amide

1-2

500

2

3-5

120 min

Lidocaine (Xylocaine) (Dalcaine)

Amide

1-2

500

2

4-6

40-60 min

Bupivacaine (Marcaine) (Sensorcaine)

Amide

0.25-0.75

175

8

5-11

4-12 hr

Etidocaine (Duranest)

Amide

1-1.5

400

8

3-5

5-10 hr

(Adapted from Raj PP: Handbook of Regional Anesthesia. Churchill Livingstone: New York, 1985; Physician’s Desk Reference for Ophthalmology Ordell NJ, Medical Economics, 1991; Crandall DC: Pharmacology of ocular anesthetics, In Duane TD, Jaeger EA (Eds): Biomedical Foundations of Ophthalmology, Harper and Row: Philadelphia, 1986)

needle injury to the nerve as it is in a relatively fixed position and cannot roll away from the needle and this could cause prolonged weakness of the facial muscles.8 Some times after the Nadbath technique dysphagia and respiratory distress can occur due to paresis of vagus, glossopharyngeal, and spinal accessory nerves, causing aspiration of oral secretion.9 Retrobulbar Injection The technique places the anesthetic in the retrobulbar space, which contains the sensory; and the motor nerves that supply the eye. Except the superior oblique this block paralyzes the rest of the ocular muscles since the trochlear nerve is outside the muscle cone. This injection is given with an 11/4 inch blunt-tipped Atkinson needle. It should ideally be given by the surgeon himself as he or she is familiar with the anatomy and not relegated to others and it should be given without putting the nerve on stretch and after making sure that the needle is not in a blood vessel by withdrawing the piston before injecting. The patient is asked to look medially and then midway between the lateral limbus and canthus at the lower orbital margin, the needle pierces the skin and is passed posteriorly parallel to the floor till it clears the equator of the globe, then the needle is angled upwards and inwards towards the apex of the orbit and pushed further to enter the muscle cone. The bevel of the needle should face the globe to reduce the chances of piercing the globe. One can often detect the passage through the muscle cone

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by noticing a slight flick of the eye and one can also rule out globe perforation by making lateral motion to note whether the tip of the needle is fixed or free. Then about 1 cc or 2 cc of the anesthetic is introduced and observation is made of the upper eyelid, which tends to droop if the injection is in the right place. Slight pressure over the eye for few minutes after the injection helps to distribute the anesthetic and within minutes the akinesia and anesthesia is obtained, the pressure applied also helps in reducing the tension of the eye. Immediately after the injection one should check the opposite eye for any paresis of the ocular muscles in the other eye and also enquire whether there is any amaurosis of the opposite eye as this will give an immediate clue to diffusion of the anesthetic along the subarachnoid space around the optic nerve in a posterior direction, and if observed immediate resuscitative measures should be instituted and oxygen administration can be started. Repeated yawning after a retrobulbar injection can also be sign of relative hypoxia and should alert the surgeon to possible respiratory depression. Peribulbar Injection There has been an increasing change to this technique to avoid the complication of the retrobulbar anesthesia. In this technique the agent is placed either in the anterior or posterior extraconal space and allowed to diffuse into the retrobulbar space posteriorly and also anteriorly to obtain an orbicularis block as well. To achieve this much larger volume of the anesthetic has to be placed and also it is preferable to use a diffusion agent like hyaluronidase and apply pressure for some time. It often takes more time than a retrobulbar injection to achieve the desired result and the incidence of incomplete akinesia and anesthesia is higher.10 Procedure of Posterior Peribulbar Block (DUANE)* With an intravenous line running or heparin lock in place and after desired sedation and eyelid preparation, proceed with the following steps; 1. Make a small skin wheal in the lower eyelid 1 cm medial to the lateral canthus over the inferior orbital rim. 2. Make a small skin wheal in the upper eyelid in the skinfold directly inferior to the supraorbital foramen. 3. Through the inferior skin wheal, with a 27-gauge needle, inject 0.5 ml of lidocaine 1% in the orbicularis and inject 1 ml just deep to the muscle. 4. Through the upper lid skin wheal, repeat as in step three. 5. Through the lower lid skin wheal, inject 1 ml of lidocaine 1 percent bupivacaine 3/4 percent hyaluronidase solution in the orbicularis muscle and 1 ml immediately deep to it. Advance along the floor of the orbit to the equator of the eye; aspirate and inject 1 ml; aiming slightly superomedially, advance the needle to its full depth and inject 1 to 1.5 ml. 6. Pushing the globe inferiorly with a free index finger, enter through the upper lid skin wheal and inject 1 ml ½ inch deep to the orbicularis muscle and slightly nearer the canthus than is the original skin wheal; direct the needle along the orbital roof without engaging the periosteum to the equator, where 1 ml is injected, then to the superior orbital fissure and inject a final 1 ml of solution. * (Adapted from Nugent CC: Peribulbar Anesthesia—A Safe, Simple Effective and Relatively Painless Technique)

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on the globe/orbit and time are essential for a good block; after 8 minutes, if incomplete remains, 3 to 4 ml of additional anesthetic solution is injected by the lower approach or inferior movement is seen, by the superior approach if superior or medial movement perform lower lid injections before upper lid).

Complications • Retrobulbar hemorrhage sometimes may result (1 to 3%)11,12 due to injury to a blood vessel and this is recognized by immediate tightening of the lids and proptosis of the globe and some times the subconjunctival appearance of the hemorrhage. Pressure over the eyeball for a few minutes may arrest a minor bleed and may allow the surgery to be undertaken. However, it is always prudent to postpone the surgery for a week and take up the case later. On most occasion no permanent damage is done to the eye. But there has been mention of optic atrophy after such an event and some times one may get occlusion of the central retinal artery. • Perforation of the globe (0.075%)13 is a serious complication which can occur with both the retrobulbar as well as peribulbar blocks and this is more often seen when a sharp disposable needle is used and its frequency is increased if the injection is made by a person not very familiar with the anatomical knowledge of the orbit. It produces immediate rise of intraocular pressure (IOP) and may also cause sharp pain. Even double perforation of the globe has been noticed when such sharp needles are used and the complication has come to be recognized only after the surgery when the retinal examination has been done. • Allergic reactions to the local anesthetic are relatively rare. Many of the socalled allergic reactions are often instances of toxicity. After routine testing for allergy to local anesthetic for fifteen years in all patients undergoing ocular surgery there was no instance where an allergic reaction was noted and hence this practice was stopped. But in a patient with known history of allergies and hypersensitivity reactions one can test for evidence for hypersensitivity taking care that emergency drugs and resuscitative measures are available. • Convulsions, tremors and confusion and other central nervous system manifestations can occur especially when inadvertent intravascular injection occurs. Alternative Methods (Table 5.3) Any new LA technique should be as safe, effective and acceptable as its predecessors. Recently, subconjunctival, sub-Tenon’s (parabulbar), and purely topical anesthesia, sometimes with additional intracameral lignocaine have become popular. All these methods of anesthesia are useful and effective if the patient assessment and selection are good and if the surgery is not prolonged. These also necessitate more interaction between the surgeon and the patient and make the surgeon alert and be aware of the patient cooperation and comfort. Patients with mental retardation, deafness, children and where communication between the operator and the subject is not possible are not suitable for such

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Local anesthesia Advantages

Disadvantages

Topical

Alert patient No retrobulbar hemorrhage, No optic nerve injury No diplopia, ptosis No globe rupture Functional vision maintained

No akinesia Inadequate anesthesia Distraction by patient

Sub-Tenon’s

Less painful No retrobulbar hemorrhage No optic nerve injury No IOP increase No globe perforation Low dose, low volume

The anesthetic has to be placed In sub-Tenon’s place correctly Absence of akinesia

Retrobulbar

Reliable Quick Less volume Loss of vision helps in patients Who do not want to see anything of the procedure

Optic nerve injury Retrobulbar hemorrhage Globe perforation Systemic complications

Peribulbar

No optic nerve injury Less chance of retrobulbar hemorrhage All advantages of retrobulbar

All disadvantages of retrobulbar less frequent Akinesia and anesthesia may be incomplete Longer to act Chemosis Ptosis Slower recovery Expensive More risky when systemic diseases of cardiopulmonary nature exist

Comfortable patient Ideal operating condition Method of choice in difficult cases No local anesthetic complication No residual paralysis bilateral surgery Better for teaching

techniques. But these techniques do abolish some of the complications associated with the retro- and peribulbar techniques. Topical anesthesia is achieved by instilling 4 percent lidocaine into the conjunctival cul-de-sac of the eye to be operated at five minute interval for about 15 minutes. A sponge soaked in the local anesthetic can be placed at the limbus so that the area can get the maximum contact with the agent. REFERENCES 1. Dejong RH: Neural blockade by local anesthetics. JAMA 238: 1383, 1977. 2. Zahl K, Jordan A, McGroarty J et al: Peribulbar anesthesia—effect of bicarbonate on mixtures of lidocaine, bupivacaine, and hyaluronidase with or without epinephrine. Ophthalmology 98: 239, 1991. 3. Eccarius SG, Gordon ME, Parelman JJ: Bicarbonate-buffered lidocaine-epinephrine-hyaluronidse for eyelid anesthesia. Ophthalmology 97: 1499, 1990.

L OCAL A NESTHESIA 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

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Goodman LS, Gilman A: The Pharmacological Basis of Therapeutics (4th ed), 1970. Mauger TF, Craig EL: Havener’s Ocular Pharmacology (6th ed), Mosby Year Book: St. Louis, 1994. Mauger TF, Craig EL: Havener’s Ocular Pharmacology (6th ed), Mosby Year Book: St. Louis, 1994. Mauger TF, Craig EL: Havener’s Ocular Pharmacology (6th ed), Mosby Year Book: St. Louis, 1994. Atkinson WS: Facial nerve block. Am J Ophthalmology 57: 144, 1964. Koenig SB, Snyder RW, Jonathan K: Respiratory distress after a Nadbath block. Ophthalmology 95: 1285, 1988. Mauger TF, Craig EL: Havener’s Ocular Pharmacology (6th ed), Mosby Year Book: St. Louis, 1994. Linn Jr JG, Smith RB: Intraoperative complications and their management. Int Ophthalmol Clin 13: 149, 1973. Cionni RJ, Osher RH: Retrobulbar hemorrhage. Ophthalmology 98: 1153, 1991. Zaturansky B, Hyams S: Perforation of the globe during the injection of local anesthesia. Ophthalmic Surg 18:585, 1987.

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Samuel Masket

Ocular Anesthesia for Small-Incision Cataract Surgery

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INTRODUCTION Traditional methods of local ocular anesthesia for cataract surgery have employed injection of anesthetics to the periorbital region. It is well recognized that regional infiltration can produce ocular anesthesia, ocular akinesia, orbicularis akinesia, and varying degrees of amaurosis. However, recent trends strongly indicate that only ocular anesthesia is necessary for routine small-incision cataract surgery. The 1997 American Society of Cataract and Refractive Surgery (ASCRS) members survey for the year 1996 suggests that roughly 15 percent of surgeons employ non-injection anesthesia (topical with or without intracameral agents) routinely.1 Nevertheless, the great majority of surgeons continue to use anesthetic injections with some degree of risks, that include damage to the globe, optic nerve, and periocular structures, and central nervous system (CNS) toxicity including brainstem anesthesia, apnea, and death. Very rarely, the patient may sustain bilateral ocular anesthesia as a result of anesthetic spread through the cavernous sinus. Moreover, with anesthetic injection, there is the potential for cosmetic blemish of the lids and conjunctiva. It is worth noting that patients often rate the quality of their cataract surgery by how the eye looks as well as how the eye sees during the early postoperative period. The risks of periorbital anesthetic injections are of some consequence, in that the overall occurrence rate for retrobulbar hemorrhage is in the vicinity of 1 percent of all cases; the likelihood increases with long needles and intraconal injection.2 Furthermore, ocular penetration and optic nerve damage are not terribly rare. The risks of those maloccurrences increase in patients who are uncooperative for injection, those with high myopia, those with prior scleral buckling surgery, and when the injections are administered by non-ophthalmologists. Additionally, no needle types,

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injection sites, or injection styles are immune to the risk for damage to the globe or other orbital structures.3-5 Another issue regarding the blind passage of sharp needles into the orbit concerns those patients on anticoagulant medications or those with naturally occurring coagulopathies. It should be obvious that these patients are at greater risk for periocular hemorrhage with needle injection, but often the medical necessity for anticoagulation dictates that patients remain on treatment during the perioperative period. Often, the systemic risk to cessation of anticoagulant treatment is greater than the risk of intraoperative bleeding. Indeed, the published guidelines for cataract surgery in the United Kingdom suggest that cataract surgery should proceed up to an INR (International Normalized Ratio) of 4.0 for patients taking Coumadin. It is evident that non-injection forms of local anesthesia are safer for anticoagulated patients. Additional consequences of periocular anesthetic include an inability of the patient to move the eye during and after surgery. While it was once considered essential that the eye be fully still for safe surgery, it is now recognized that purposeful eye movements, on command, can benefit the progress of surgery. As an example, in cases with narrow palpebral fissures, the eye can be moved to facilitate incisions, etc. A further consequence of regional anesthetic infiltration is amaurosis. As a result, the patient cannot see to fixate a target. However, with topical/intracameral anesthesia, the patient can be asked to follow a light source or other visual target to help fixate the globe in a satisfactory position for surgery. Movement away from periocular injection toward topical methods of ocular anesthesia is natural, given the overall changes in small-incision cataract surgery that have progressed to outpatient surgery with methods that allow for immediate ambulation, rapid return to a full lifestyle, and stable optical results of surgery within days.6 The immediate use of the eye after cataract surgery is possible only with topical or intracameral methods and is in keeping with the concepts of modern surgery. Topical anesthesia resurfaced in this decade as a useful tool after Fichman’s suggestion regarding the use of tetracaine 0.5 percent applied to the eye as the only anesthetic for cataract surgery.7 Other agents, such as bupivacaine and lidocaine have been popularized because of a reduced tendency to cause corneal epitheliopathy and to have a longer period of action as compared with tetracaine. However, patients are not universally comfortable with topical anesthesia as the only agent. Many surgeons employ small amounts of intravenous, oral, or sublingual sedation as an adjunct. However, in 1995 Gills suggested the routine use of intracameral nonpreserved lidocaine in addition to topical anesthesia with or without systemic sedation,8 although the concept had been mentioned earlier by Fichman who considered intraocular tetracaine for use in difficult case situations. Safety and efficacy of intracameral lidocaine has been further established by Koch9 and Masket with Gokmen in separate studies.10 In the latter investigation, approximately 40 percent of greater than 300 patients receiving only topical anesthesia required intraoperative conversion to a deeper level of local anesthesia, whereas fewer than 1 percent of 300 cases receiving intracameral lidocaine had need for an additional local anesthetic

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method. In the same study safety was measured by comparing the degree of corneal edema on the first postoperative day between the two groups, a reduced likelihood for corneal edema was associated with the use of intracameral nonpreserved lidocaine hydrochloride 1 percent, but this finding may be related to the use of chop style phacoemulsification for the latter group. Nevertheless, based upon the early postoperative appearance of the cornea, non-preserved lidocaine is seemingly non-toxic although Koch reports reduced contrast sensitivity Fig. 6.1: Blunted reusable cannula for subTenon’s (parabulbar) anesthesia (Courtesy and visual acuity in the first few hours Rhein Medical, Tampa, Florida) after surgery. Other methods to provide ocular anesthesia for cataract surgery without the risks of blind pass, sharp needle orbital injection have evolved during the same era as the movement to topical anesthesia. Posterior sub-Tenon’s infiltration employs a blunt cannula (Fig. 6.1) to place local anesthesia directly in the retrobulbar space. A conjunctival button hole incision, performed under topical anesthesia, is necessary for the cannula to gain direct access to the sub-Tenon’s space. This method was suggested as an alternative to sharp needle orbital injection,11 and has been further popularized by Greenbaum as a primary method for cataract anesthesia; he coined the term “parabulbar” anesthesia to describe the concept.12 Additionally, the method may be used for surgeons in transition to topical/intracameral anesthesia and is very useful to convert from topical methods in cases where complications occur, surgery is prolonged, or if the patient is otherwise in need of a deeper level of anesthesia. As long as the cataract incision is self-sealing, the parabulbar infiltration may be given at any time during the surgery. Varying with the nature of the agent used for infiltration, parabulbar anesthesia may provide complete ocular akinesia and amaurosis. Other alternatives include anterior subconjunctival injection given diffusely or only focally in the region of the incision, so-called “pin-point” anesthesia.13 It is evident that traditional ocular anesthesia for cataract surgery, utilizing sharp needles passed blindly through the skin of the lids or the conjunctiva engenders risks (Table 6.1) that are avoidable with topical or intracameral or other recently developed means for local anesthesia. However, in addition to the greater safety associated with newer anesthetic systems, topical and topical or intracameral methods avoid the need for patching and allow patient the use of the eye immediately following surgery in the overwhelming majority of cases. Advantages, therefore, include safety, improved cosmesis, ability to use the eye immediately following surgery, and the ability to move and fixate the eye during surgery in response to the surgeon as an aid to the procedure (Table 6.2). Varying with the experience of the surgeon, certain conditions may contraindicate the use of topical/intracameral anesthesia (Table 6.3). Given the ability to move

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Table 6.1: Risks of injection anesthesia _______________________________________________________________________________________________________________________________________________________________________________ • Damage to optic nerve • Retrobulbar hemorrhage • Ocular penetration/perforation • Central nervous system anesthesia • Apnea • Unintended bilateral ocular anesthesia • Damage to extraocular muscles/diplopia • Esthetic blemish _______________________________________________________________________________________________________________________________________________________________________________ Table 6.2: Advantages of topical/intracameral anesthesia _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ • Avoids pain, blemish and risk of injection anesthesia • Allows immediate useful vision after surgery • Eliminates need for patch after surgery • Reduces anxiety and/or heavy sedation associated with injection anesthesia • Compatible for patients on anticoagulants • Patients can aid surgeon by moving eye for favorable exposure _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Table 6.3: Contraindications to topical/intracameral anethesia ____________________________________________________________________________________________________________________________________________________________________________________ A. Relative 1. Language barrier 2. Anticipated difficult surgery 3. Poorly cooperative patient B. Absolute 1. Total deafness 2. Coarse nystagmus ____________________________________________________________________________________________________________________________________________________________________________________

the eye, the patient can aid in the surgery or create significant obstacles; cataract surgery under topical or intracameral anesthesia is, by necessity, interactive. Poor patient cooperation is a relative contraindication, as is the inability of the surgeon and patient to adequately communicate in the same language. Often, an interpreter or bilingual family member can be present in the operating theater in order to facilitate surgery without need for injection anesthesia. However, absolute congenital deafness with speaking difficulty is an absolute contraindication, since the patient may become disoriented under the surgical drapes and cannot be expected to communicate by the usual means of lipreading or sign language; patients of this nature often require general anesthesia. Ocular conditions may also act as relative or absolute contraindications; cataracts too dense to allow fixation on the microscope light, potentially complicated surgery (preoperative zonulysis, etc.), and nystagmus are common examples. Nevertheless, the huge majority of patients may safely experience small-incision cataract surgery under topical/intracameral anesthetic with very limited sedation. Methods The author prefers the use of lidocaine HCl 4.0 percent non-preserved for topical anesthetic. It is long acting and non-mucogenic (Previous experience with 0.75 percent

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bupivacaine HCl suggests that it causes undesired mucous production.) Intracameral anesthesia is achieved with unpreserved lidocaine HCl 1.0 percent. Some surgeons advocate diluting the intracameral agent with BSS solution in order to raise the pH and reduce the mild discomfort associated with anterior chamber instillation. • Administer topical proparacaine HCl 0.4 percent to initiate anesthesia with little sting. Administer dilating agents (cyclopentolate or tropicamide and phenylephrine 2.5%), topical antibiotics, a topical NSAID, and lidocaine HCl 4.0 percent four times at five minute intervals prior to surgery. • After the patient is brought into the theater several drops of the 4.0 percent lidocaine are administered prior to the sterile “prep”. The latter begins with instillation of two drops of half strength Betadine solution (not Betadine scrub) directly to the operative eye. At this time very small amounts of intravenous sedation may be given, depending upon the mental and medical status of the patient, the anxiety of the surgeon, and the observations of the anesthetist or equivalent. The author generally asks that 0.5 mg to 1.0 mg of midazolam HCl be administered IV. • During the draping process communicate with the patients about the operative process. Tell them that they will feel slight pressure from the lid speculum and that they will need to fixate on the light of the microscope. Tell them that requests to look up, down, etc. should be achieved by moving the eye and not the head. Reassure them that they will feel no pain. • Begin surgery with the microscope light at low levels of illumination, sufficient only to perform a paracentesis. Place 0.2 cc of non-preserved lidocaine HCl in the anterior chamber and follow that with the viscoelastic of choice. The anesthetic will be washed out as the viscoagent fills the chamber if the lip of the sideport is depressed as the viscoelastic is injected. Slowly increase the microscope light and perform the clear-corneal incision. Continue with routine surgical procedure. • Generally, no further anesthesia is necessary. However, in situations with prolonged surgery or very sensitive patients, additional intracameral anesthetic may be administered for complaints of “pressure“ or intraocular pain. For surface discomfort the conjunctiva may be swabbed with a pledget of any sterile topical anesthetic, but care should be taken to avoid placing the agent near or in the incision if it contains preservatives. Additionally, small increments of intravenous sedation can be added as may be (rarely) necessary. • In the very unlikely case that the patient cannot tolerate the microscope light even at low illumination and continues to squeeze the lids against the speculum, additional doses of IV medicine could be given until the intracameral anesthetic is administered. In the author’s observations, once the eye has received the intracameral agent, all lid squeezing and signs of anxiety or discomfort abate rapidly. However, in extreme situations or should an operative complication occur that will significantly prolong surgery, one can stop surgery, given a self-sealing incision, pressurize the eye to normal, and administer deep sub-Tenon’s local anesthetic with a blunt cannula (Fig. 6.1) through a conjunctival buttonhole entry in the superior or inferior nasal quadrant.

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Prior to incising the conjunctiva, a pledget of local anesthesia may be placed on the area for a few moments. The cannula should reach the retrobulbar space with ease if the buttonhole opening includes Tenon’s capsule. Only 2.0 cc of local agent is necessary, given direct access to the muscle cone. Relative amaurosis will be achieved in a matter of seconds, and, with strong local agents, akinesia can be established in a few minutes. REFERENCES 1. Leaming DV: Practice styles and preferences of ASCRS members—1996 survey. J Cataract Refract Surg 23:527-35, 1997. 2. Cionni R, Osher R: Retrobulbar hemorrhage. Ophthalmology 98:1153-55, 1991. 3. Duker JS, Belmont, JB, Benson WE et al: Inadvertent globe perforation during retrobulbar and peribulbar anesthesia. Ophthalmology 98:519-26, 1997. 4. Hay A, Flynn Jr HW, Hoffmann JI et al:. Needle penetration of the globe during retrobulbar and peribulbar injections. Ophthalmology 98:1017-24,1991. 5. Grizzard WS, Kirk NM, Pavan PR et al: Perforating ocular injuries caused by anesthesia personnel. Ophthalmology 98:1011-16, 1991. 6. Masket S, Tennen DG: Astigmatic stabilization of 3.0 mm temporal clear corneal cataract incisions. J Cataract Refract Surg, 22(10):1451-55, 1996. 7. Fine IH, Fichman RA, Grabow HR: Clear-corneal Cataract Surgery and Topical Anesthesia. Slack Inc: Thorofare, 1993. 8. Gills JP, Cherchio M, Raanan MG: Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia. J Cataract Refract Surg 23:545-50, 1997. 9. Koch PS: Anterior chamber irrigation with unpreserved lidocaine 1% for anesthesia during cataract surgery. J Cataract Refract Surg 23:551-54, 1997. 10. Masket S, Gokmen F: Efficacy and apparent safety of intracameral lidocaine as a supplement to topical anesthesia. J Cataract Refract Surg (24)7:956-60, 1997. 11. Stevens JD : A new local anaesthesia technique for cataract extraction by one quadrant sub-Tenon’s infiltration. Br J Ophthalmol 76:670, 1992. 12. Greenbaum S: Anesthesia in cataract surgery. In Greenbaum S (Ed): Ocular Anesthesia WB Saunders: Philadelphia 1-55, 1997. 13. Fukasaku H, Marron JA: Pinpoint anesthesia—a new approach to local ocular anesthesia. J Cataract Refract Surg 20:468, 1994.

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Shashi Kapoor

The limbal Incision

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INTRODUCTION Kratz is credited as the first surgeon, to move from the limbus posteriorly to the sclera, increasing appositional surfaces to enhance wound healing and attempt to exert less traction on the cornea, thereby controlling surgically induced astigmatism. Girard and Hoffmann were the first to call the posterior incision a “scleral tunnel” incision. In 1989, McFarland and Ernst introduced an incision architecture that allowed the phacoemulsification and implantation of lenses without the need for suturing. Besides lengthening the scleral tunnel, this incision terminated in a decidedly corneal entrance and the posterior lip of the incision, the so-called corneal lip, acted as one-way valve imparting to this incision its self-sealing characteristics. Paul Koch described what he called the `incision funnel’ indicating that there were certain characteristics of self-sealing incisions with respect to length and configuration that imparted not only self-sealability but also astigmatism neutrality to these incisions. The advent of the foldable IOL and advances in device technologies have led to significant refinements in small incision surgery and wound closure that are revolutionizing the practice of cataract surgery. These clinical advances are leading to reductions in iatrogenic ocular trauma and postoperative astigmatism, decreased risk of hyphema, delayed filtering blebs and iris prolapse, increased wound stability, and faster recovery and vision restoration. Posterior Limbal Incision Ernst et al are advocating the use of the temporal posterior limbal incision, which can be made nearly square for foldable IOLs (3.2 mm × 3.0 mm). In a cadaver

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Fig. 7.1: Square corneal wound, 3.5 × 3.5 mm, is impractical since it impinges on the visual axis, and causes disturbing striae, intraoperatively

Fig. 7.2: Square corneal wound, 2 × 2 mm (1.5 mm being the minimal internal corneal lip) is impractical, as it is too small to permit the insertion of current phaco tips and IOLs

eye studies, as rectangular clear corneal incisions were made more square by only 0.5 mm from 3.2 mm × 2.0 mm to 3.0 mm × 2.5 mm, they became more resistant to pressure. Once the length was increased so that the wounds were square (3.2 mm × 3.2 mm) with a 1.5 mm internal corneal lip, they were capable of withstanding maximal external pressures of 525 psi. As yet, square clear corneal incisions are clinically impractical, because they either encroach upon the visual axis (Fig. 7.1) or are too small to permit the insertion of current phaco tips and IOLs (Fig. 7.2). The limbal incision has several advantages over the currently advocated clear corneal incision. Clear corneal incisions, especially those that have a vertical component, are more subject to foreign body sensation than limbal incisions. This irritation occurs because there is edema of both the anterior and posterior aspects of the incision in clear corneal incisions with vertical components, which creates a gape in the most superficial aspect of the incision (Figs 7.3A and B). In turn, this gape forms a ridge that can irritate the patient. Dr Tipperman et al, performed a feline study evaluating limbal versus clear corneal incisions. The incision dimensions were non-square, 3.00 mm in width and 1.75 mm in length. A paracentesis type incision was made in each case. Reformation of the anterior chamber and stromal hydration were not performed. The eyes were observed over a period of 16 days. Pinpoint pressure was applied to each eye at various time intervals. The results showed a statistically significant

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Fig. 7.3A: Schematic drawing of a clear corneal incision postphacoemulsification showing corneal edema and ridge

Fig. 7.3B: Schematic diagram of a limbal incision postphacoemulsification showing edema of the corneal tunnel, but not edema of the incision

difference in resistance to pinpoint deformation pressure between the limbal and paracentesis incision (P = 0.0034) (Fig. 7.4). Incision Design The design of modern sutureless, self-sealing cataract incisions, involves the consideration of three design parameters, site, size and shape. Incision Shape Shape is an anatomic parameter in the geometric consideration of cataract incision construction. There are two aspect views of these incisions: sagittal and anteroposterior; and three components: the external incisions, the intratissue tunnel and the internal incision. From the sagittal aspect, limbal incisions may be made in one of following configurations varying, between single-plane, grooved beveled and triplane with a groove and a bevel. The external component of limbal incisions also may be in one of the following theoretical configurations: the single-step “stab” incision as initially introduced by Howard Fine; the two-step grooved incision by Charles Williamson, who felt that the incision should be larger on the outside than the inside, which would allow the injector to fit more easily in the incision without stretching the sclera.

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Fig. 7.4: Graph comparing resistance deformation pressure of clear corneal (CC) and limbal incisions (LB) over time

The ultimate goal is to have no tissue stretch. The trapezoid incision that Dr Williamson describes are about 0.5 mm wider on the outside than the inside. Langerman Hinge and Gills Modification Langerman and Gills have modified clear corneal incisions, and these modifications are applicable to limbal incisions. Although clear corneal incisions appear to be watertight at the end of surgery, Langerman and Ernst have shown that both the straight-in and two-plane clear corneals can leak. This ability to leak indicates a less than perfect seal. John has shown a higher incidence of sterile endophthalmitis in clear corneals compared to scleral tunnels. This increased incidence is probably due to reflux of flora into the anterior chamber through the incision. The lack of culture positive infection can be attributed to John’s aggressive prophylactic antibiotic regimen, after the Gills method. Langerman has developed a hinge technique which involves making the initial vertical groove deeper than the point at which the horizontal shelf is started (Fig. 7.5). The deep groove then functions as a hinge, with the inner aspect of the incision flexible and malleable, allowing it to adhere to the outer portion of the incision.

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The Gills modification of the Langerman hinge involves a vertical incision that is 85% deep. The next step is to create a deep longitudinal bevel in the stroma in either a single-or twoplane fashion. This portion is deeper and longer than Langerman describes. Because the inner flap is very thin, it allows for greater flexibility and better contact when pressure is applied to any portion of the wound. Fig. 7.5: Schematic drawing demonstrating The key to creating a very deep, thin wound construction incision is to pick up the distal aspect of the limbal wound with forceps. This step is essential for two reasons: (i) it allows the surgeon to have control over fixation of the eye when using topical anesthesia, and (ii) it allows the surgeon to make a deep incision with greater ease. The flap is created by directing the keratome (diamond or metal) toward the dome of the eye. After tunneling through the posterior stroma for a distance of approximately two-thirds the keratome width, the incision is beveled posteriorly through Descemet’s membrane and into the anterior chamber. Using a 2.3 mm to 2.5 mm trapezoidal keratome and beveling it into the anterior chamber approximately 2 mm will create a 2.3 mm to 2.5 mm by 2.0 mm incision. The incision performs similarly to navigational valves, when pressure against the rubber forces the aperture closed. Grooved incisions provide a superficial corneal flap that has a thicker edge, which helps to avoid avulsion when grasping with forceps or when suturing. The deep groove of Langerman is believed to physically separate the sclera from the internal corneal flap sufficiently to allow sclera indentation (patient rubbing) without internal wound separation, thereby reducing the potential for wound leak. The sagittal shape and direction of the tunnel may also vary. Most tunnels are made flat or planar by flat blades advanced in a single plane. Some surgeons believe there may be superior sealability with a convex sagittal curve to the tunnel although it is technically difficult to create and to reproduce. The third component of these incisions, the internal opening, may have one of two sagittal shapes: single-plane “stabs” in the same plane as the limbocorneal tunnel (Fig. 7.6), or bi-planar “steeped”. In addition, Singer proposes that the most Fig. 7.6: Limbocorneal tunnel incision accurate anatomic angle of entry into

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Figs 7.7A to C: Anteroposterior aspect of limbaltunnel (Grabow): (A) convergent trapezoid, (B) parallelogram, and (C) divergent trapezoid

the anterior chamber through the endothelial surface is 17.5 degrees, that which duplicates the average angle of perforation of scleral veins. The anteroposterior aspect of the second component of limbal incisions, the tissue tunnel, is summarized in Figures 7.7A to C. The original configuration was parallelogram introduced by Fine. The second configuration, was a convergent trapezoid, introduced by Williamson. In this design, the external incision is longer than the internal incision, to improve instrument maneuverability while preserving the smallest internal opening for self-sealability. The third configuration, the divergent trapezoid of Hoffer, has its external opening smaller than its internal opening, to reduce the astigmatic effect, while allowing maneuverability internally. The anteroposterior aspect of the third incisional component, the internal opening has only recently come under investigation. Three directional possibilities exist for this incision (Figs 7.8A to C): limbus-parallel, tangential and limbus-antiparallel (“corneal frown”). Limbus-parallel internal incisions, unlike limbus parallel external incisions, have been demonstrated to be the most stable and most resistant to deformation and leakage. Conversely, corneal frown internal incisions are the weakest. Therefore, cutting strokes to enlarge an internal incision should move either in a central direction, by advancing the blade, or in a lateral direction, so as to preserve a limbus-parallel configuration, rather than in a peripheral direction, as when withdrawing the blade.

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Figs 7.8A to C: Anteroposterior aspect of internal corneal openings (Grabow): (A) limbus parallel, (B) tangential, and (C) limbusantiparallel “corneal frown”

Site One classification of location of cataract incisions, involves the radial distance from the optic axis. These locations for cataract incisions have traditionally been designated by their anatomic locations; the sclera, the cornea, and the junction of these two—the limbus. Scleral Incisions Scleral incisions, being furthest from the optic axis, when compared to corneal and limbal incisions of equal dimension, have less effect on both corneal astigmatism and the corneal endothelium, and the same is true for peripheral corneal incision as compared to more central corneal incisions. The external entry incision for small, self-sealing sclerocorneal incisions, as originally described was made 3 to 4 mm posterior to the limbus. The distance from the limbus has become progressively less as surgeons have become more conversant with creating the self-sealing internal corneal lip. Now most surgeons are comfortable about 1.5 mm posterior to the limbus, giving a total sclerocorneal tunnel length of approximately 2.5 to 3.0 mm. In 1972, Fine introduced the clear corneal incision, which was originally described as a stab incision temporally located in avascular tissue. Since then, many modifications and variations have been developed, encompassing a wide variety of sutureless incisions.

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Limbal Incision Anatomists describe the anterior vascular arcade as extending 0.5 mm into clear cornea, anterior to the limbus with its external surface covered by conjunctiva. Thus the limbus can be defined as the anterior edge of the conjunctival insertion, with the corneal vascular arcade considered to be in clear cornea. Architecturally, limbal incisions can be described as follows. a. Single plane (without a vertical groove at the external edge of the incision) b. Shallow groove (having a groove perpendicular to the corneal surface at the external edge of the incision, upto 400 µ deep) c. Deeply grooved (where the groove perpendicular to the external edge of the incision is greater than 400 µm). In another classification, the cataract incision is usually described as located at one of four possible sites on the corneal circle superiorly, obliquely, temporally or on steep axis. Superiorly located incisions when not under the influence of sutures, are known to have an against-the-rule (ART) astigmatic effect, greater with longer incisions, due to the effects of gravity and/or lid closure on wound gape. The oblique location, whether nasal or temporal, is espoused by some who prefer this site not only for ergonomic advantage, but also for greater wound stability when compared to superior incisions. These wounds are believed by some to be the only ones not affected by transmitted tractional forces of a rectus muscle, a theory yet to be documented. Superolateral Incisions It has been reported that a lateral or superolateral incision, can decrease and quickly stabilize surgically induced astigmatism (SIA), although the reason for this is unclear. Hayashi et al compared superior (group I) with superolateral incisions (Group 2) in IOL patients who underwent a 6.5 mm beveled incision, 0.5 mm posterior to the surgical limbus, followed by endocapsular phacoemulsification, enlargement of incision to 6.5 mm and insertion of a posterior chamber IOL with a 6.0 mm optic. The wound was closed by 3 interrupted 10-0 nylon sutures. The patients were followed up using keratometer and computerized corneal topography. Figure 7.9 shows the induced changes in the mean keratometric cylinder at each interval, in the two groups. Group 1 has significantly less induced astigmatism throughout the six month follow-up than group 2. The patients in group 1 also had less standard deviation throughout the follow-up than the patients in group 2. This indicates that SIA in group 1 was less variable than in group 2. Two types of corneal topographic maps were used to illustrate the postoperative corneal shape alterations: color-coded maps “averaging” all corneas at each interval and absolute scale maps of individual cases. The averaged maps of Group 1 patients show a slight steepening in the central cornea in the 10 O’clock meridian, one week after surgery. There were no remarkable changes in the peripheral cornea. The surgically induced steepening in the central cornea disappeared within one

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Fig. 7.9: (Hayashi) Mean (standard deviation) induced keratometric cylinder following superolateral incision and superior incision surgery using the vector analysis method. The mean induced keratometric cylinders in group 1 were significantly less than those in group 2 throughout the six month follow-up. The standard deviations in group 1 were also smaller than those in group 2

month after surgery. Consequently, in group 1, the averaged maps of the corneas, after 1 month were virtually the same as the map of preoperative corneas. The averaged maps of group 2 patients show a marked steepening of the upper and lower corneas, in the vertical meridian, one week after surgery. This induced steepening gradually decreased but remained upto three months. The averaged map of the cornea at “six“ months after surgery, was almost the same as the preoperative map (as compared to one month, group 1). Absolute scale maps of a patient in Group 1 reveal remarkable changes in the corneal shape after surgery. There was prominent corneal steepening in the 10 O’clock meridian and the map shows an asymmetric horizontal bow-tie configuration one week after surgery. This steepening quickly disappeared; at three and six months after surgery the cornea had almost recovered it’s preoperative shape, although a focal steepening in the horizontal meridian remained (Fig. 7.10). In group 1 19.7 percent of corneas showed this prominent steepening, just after surgery. Figure 7.11 shows a patient from group 2. Marked steepening of the upper and lower corneas occurred at one week and is shown as a vertical bow-tie configuration. The steepening did not change substantially during the six-month follow-up. In group 2, 68.4 percent of corneas, showed this marked corneal steepening. Thus, superolateral incision cataract surgery induced minimum changes in the corneal shape, as well as SIA, and the changes decreased quickly and stabilized in the early postoperative period. One cannot explain why the induced corneal shape changes are less with the superolateral approach. The differences between

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Fig. 7.10: (Hayashi) Absolute scale maps of a cornea in the superolateral incision group: (A) Preoperatively, and (B) at 3 months postoperatively. After 3 months the map was almost same as preoperatively

Fig. 7.11: (Hayashi) Absolute scale maps of a cornea in the superior incision group: (A) Preoperatively and (B) at 3 months postoperatively. At three months the steepening in the upper and lower corneas, did not change substantially

the semilateral and superior incision surgeries were only related to the wound site. There are a few anatomical differences between the horizontal and the superior limbus. Alternatively, some unknown physiologic and/or optical factor may exist. The rapid stabilization with the superolateral incision appeared to be rather easy to explain. Continuous stroking of the upper eyelid causes pressure on the superior corneoscleral wound. Therefore corneal distortion by the superior wound persists longer. A superolateral incision is relatively free from such eyelid pressure and corneal shape changes stabilize faster. Thus, superolateral incision surgery appears to have advantages, although the exact mechanism remains unproven. The temporal location has been shown to be the most astigmatically stable of these three locations, achieving stability almost immediately and maintaining stability for life or until further astigmatic interventions. First, the temporal location is furthest from the visual axis, and so there will be less impact on the corneal curvature at the visual axis. Second the wound is parallel to the effects of both lid blink and gravity. The temporal location has an added advantage in that it provides the easiest anatomic access to the surgical site, being unimpeded by the bony orbital rim.

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Fig. 7.12: Clear corneal incision, 1 week postsurgery showing no wound healing

Fig. 7.13: Limbal incision, 1 week postsurgery demonstrating significant fibroblastic activity completely sealing the incision

Fig. 7.14: Two-month postsurger y, clearcorneal incision demonstrating the incision is healed through binding of the stromal keratocytes as seen in corneal transplant surgery

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In their fourth cadaver study of clear corneal incisions Ernst et al reported that when clear corneal incisions of exactly the same dimensions were made at the limbus and anterior to the limbus, the one nearer the limbus demonstrated greater

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Fig. 7.15: Two-month postsurgery, limbal incision, showing the same fibroblastic activity and the same degree of healing as 1 week postsurgery

wound stability. The reason of this is not completely clear. It may be that the architecture of the limbus, with its circumferential fibers allows greater resistance than the radial fibers of the cornea. The limbus also contains more elastic fibers than the cornea, which has none. Histologic evaluations at 1 week showed no healing activity of the clear-corneal incision (Fig. 7.12). The limbal incision, whether it was placed anteriorly or posteriorly, showed a significant fibroblastic response causing the wound to seal (Fig. 7.13). Both limbal and corneal incisions heal by fibroblast response. The key is the timing of the healing process: 7 days for vascular origin (limbal incisions) and 60 days for avascular origin (corneal incisions). Limbal incisions heal by an influx of fibroblasts in the vascular arcade or through the differentiation of stem cells into fibroblasts. They heal faster than corneal incisions, which heal in a way similar to that of corneal transplants, in which binding stromal keratocytes transform into fibroblasts (Figs 7.14 and 7.15). The advantages of moving to a temporal approach and more posterior into a vascular region (limbal incisions) allow an earlier fibroblast response that seals incisions faster than the 60 days required for incisions made in an avascular region (corneal incisions).

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Amar Agarwal Athiya Agarwal Sunita Agarwal

No Anesthesia Cataract Surgery

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INTRODUCTION On June 13th, 1998 at Ahmedabad, India the authors (Amar Agarwal) did the first No anesthesia cataract surgery at the Phaco and Refractive Surgery Conference. This was performed as a live surgery in front of 250 delegates. This has opened up various new concepts in cataract surgery. Phacoemulsification Since the introduction of phacoemulsification as an alternative to standard cataract extraction techniques, surgeons throughout the world have been attempting to make this new procedure safer and easier to perform while assuring good visual outcome and patient recovery. The fundamental goal of phaco is to remove the cataract with minimal disturbance to the eye using least number of surgical manipulations. Each maneuver should be performed with minimal force and maximal efficiency should be obtained. The latest generation phaco procedures began with Dr Howard Gimbel’s “divide and conquer” nuclear fracture technique in which he simply split apart the nuclear rim. Since then we have evolved through the various techniques namely four quadrant cracking, chip and flip, spring surgery, stop and chop and phaco chop. The phaco chop technique was developed and introduced by Dr Nagahara to reduce total phaco time and power needed to remove the cataractous lens. In this technique the tip is embedded in the superior half of the nucleus using shallow sculpturing motion. The tip of the chopper is introduced into the nucleus at the 6 O’clock position by penetrating the lens cortex and epinucleus. The two

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Fig. 8.1: Eye with cataract

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Fig. 8.2: Left hand injects viscoelastic using a 26-gauge needle

instruments create the nuclear fracture. The nucleus is rotated and the process repeated to get 4 to 6 fragments. Each quadrant is then emulsified. This chopping does peripheral chopping. In other words, the nucleus is chopped from the periphery. Agarwal Karate Chop Technique Incision A temporal clear-corneal section is made. If the astigmatism is plus at 90 degrees then the incision is made superiorly. first of all, in the cataractous eye (Fig. 8.1) a needle with viscoelastic is injected inside the eye in the area where the second site is made (Fig. 8.2). This will distend the eye so that when you make a clear corneal incision, the eye will be tense and one can create a good valve. Now use a straight rod to stabilize the eye with the left hand. With the right hand make the clear-corneal incision (Fig. 8.3). When we started making the temporal incisions, we positioned ourselves temporally. The problem by this method is that, every time the microscope has to be turned which in turn would affect the cables connected to the video camera. Further the theater staff would get disturbed between right eye and left eye. To

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Fig. 8.3: Clear corneal incision. Note the straight rod inside the eye in the left hand. The right hand is performing the clear corneal incision. This is a temporal incision and the surgeon is sitting temporally

Fig. 8.4: Rhexis being done with a needle

solve this problem, we then decided on a different strategy. We have operating trolleys on wheels. The patient is wheeled inside the operation theater and for the right eye the trolley is placed slightly obliquely so that the surgeon does not change his or her position. The surgeon stays at the 12 O’clock position. For the left eye the trolley with the patient is rotated horizontally so that the temporal portion of the left eye comes at 12 O’clock. This way the patient is moved and not the surgeon. Rhexis Capsulorrhexis is then performed through the same incision (Fig. 8.4). While performing rhexis it is important to note that the rhexis is started from the center and the needle moved to the right and then downwards. This is important because today concepts have changed to temporal and nasal. It is better to remember it as superior, inferior, right or left. If we would start the rhexis is generally where you finish it. In other words, the point where you tend to lose the rhexis is near its completion. If you have done the rhexis from the center and moved to the left, then you might have an incomplete rhexis on the left hand side either

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inferiorly or superiorly. Now, the phaco probe is always moved down and to the left. So every stroke of your hand can extend the rhexis posteriorly creating a posterior capsular rupture. Now, if we perform the rhexis from the center and move to the right and then push the flap inferiorly—then if we have an incomplete rhexis near the end of the rhexis it will be superiorly and to the right. Any incomplete rhexis can extend and create a posterior capsular tear. But in this case, the chances of survival are better. This is because we are moving the phaco probe down and to the left, but the rhexis is incomplete up and to the right. If you are a left-handed person start the rhexis from the center and move to the left and then down. Hydrodissection Hydrodissection is then performed (Fig. 8.5). We watch for the fluid wave to see that hydrodissection is complete. We do not perform hydrodelineation or test for rotation of the nucleus. Viscoelastic is then introduced before inserting the phaco probe. Fig. 8.5: Hydrodissection

Karate Chop—Two Halves We then insert the phaco probe through the incision slightly superior to the center of the nucleus (Fig. 8.6). At that point apply ultrasound and see that the phaco tip gets embedded in the nucleus (Fig. 8.7). The direction of the phaco probe should be obliquely downwards toward the vitreous and not horizontally towards the iris. Then only the nucleus will get embedded. The settings at this stage are 70 percent phaco power, 24 ml/minute flow rate and 101 mm of Hg suction. By the time the phaco tip gets embedded in the nucleus the tip would have reached the middle of the nucleus. We do not turn the bevel of the phaco tip downwards when we do this step, as the embedding is better the other way. We prefer a 15-degree tip but any tip can be used. Now stop phaco ultrasound and bring your foot to position 2 so that only suction is being used. Now lift the nucleus. When we say lift it does not mean lift a lot but just a little so that when we apply pressure on the nucleus with the chopper the direction of the pressure is downwards. If the capsule is a bit thin like in hypermature cataracts you might rupture the posterior capsule and

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Fig. 8.6: Phaco probe placed at the superior end of the rhexis

Fig. 8.7: Phaco probe embedded in the nucleus. We started from the superior end of the rhexis and note it has got embedded in the middle of the nucleus. If we had started in the middle then we would have embedded only inferiorly that is at the edge of the rhexis and chopping would be difficult. Note the tip of the phaco is not seen as it is fully embedded

create a nucleus drop. So when we lift the nucleus the pressure on the posterior capsule is lessened. Now, with the chopper cut the nucleus with a straight downward motion (Fig. 8.8) and then move the chopper to the left when you reach the center of the nucleus. In other words, your left hand moves the chopper like an inverted L. Remember—do not go to the periphery for chopping but do it at the center. Once you have created a crack, split the nucleus till the center. Then rotate the nucleus 180 degrees and crack again so that you get two halves of the nucleus. In brown cataracts, the nucleus will crack but sometimes in the center the nucleus will still be attached. You have to split the nucleus totally in two halves and you should see the posterior capsule throughout. Karate Chop—Further Chopping Now that you have two halves, you have a shelf to embed the probe. So, now place the probe with ultrasound into one half of the nucleus (Fig. 8.9). You can

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Fig. 8.8: Left hand chops the nucleus and splits like an inverted L shape, that is downwards and to the left. When the crack is complete, you should see posterior capsule throughout the crack

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Fig. 8.9: Embed the probe in one-half of the nucleus. Go horizontally and not vertically as you have now a shelf of nucleus to embed

pass the direction of the probe horizontally as now you have a shelf. Embed the probe, then pull it a little bit. This step is important so that you get the extra bit of space for chopping. This will prevent you from chopping the rhexis margin. Apply the force of the chopper downwards. Then move the chopper to the left so that the nucleus gets split. Again, you should see posterior capsule throughout so that you know the nucleus is totally split. Then release the probe, as the probe will still be embedded into the nucleus. Like this create three quadrants in one half of the nucleus. Then make another three halves with the second half of the nucleus. Thus, you now have 6 quadrants or pie-shaped fragments. The settings at this stage are 50 percent phaco power, 24 ml/minute flow rate and 101 mm of Hg suction. Remember 5 words—embed, pull, chop, split and release. Pulse Phaco Once all the pieces have been chopped, take out each piece one by one and in pulse phaco mode aspirate the pieces at the level of the iris. Do not work

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Fig. 8.10: Cortical aspiration done

Fig. 8.11: Cortical aspiration completed. Note the straight rod in the left hand, which helps control the movements of the eye

in the bag unless the cornea is preoperatively shows signs of inadequate endothelial cells, or the patient is very elderly. The setting at this stage can be phaco power 30-50 percent, flow rate 24 ml, and suction 100 mm of Hg. Cortical Washing and Foldable IOL Implantation The next step is to do cortical washing (Fig. 8.10). Always try to remove the subincisional cortex first, as that is the most difficult. In Figure 8.11 note the cortical aspiration complete. Note also the rhexis margins. Note also that everytime the left hand has the straight rod controlling the movements of the eye. If necessary use a bimanual irrigation-aspiration technique. Then inject viscoelastic and implant the foldable IOL. We use the plate haptic foldable IOL (Fig. 8.12) with large fenestrations generally as we find them superior. Take out the viscoelastic with the irrigation-aspiration probe (Fig. 8.13). Stromal Hydration At the end of the procedure, inject the BSS inside the lips of the clear corneal incision (Fig. 8.14). This will create a stromal hydration at the wound. This will

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Fig. 8.12: Plate haptic foldable IOL being implanted

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Fig. 8.13: Viscoelastic removed with the irrigation aspiration probe

create a whiteness, which will disappear after 4 to 5 hours. The advantage of this is that the wound gets sealed better. Pad, S/C Injections No subconjunctival injections or pad are put in the eye. The patient walks out of the theater and goes home. The patient is seen the next day and after a month glasses prescribed. Agarwal Chopper We have devised our own chopper. The other choppers, which cut from the periphery, are blunt choppers. Our chopper is a sharp chopper. It has a sharp cutting edge. It also has a sharp point. The advantage of such a chopper is that you can chop in the center and need not go to the periphery to make the chop. In this method by going directly into the center of the nucleus, without sculpting, ultrasound energy required is reduced. The chopper always remains within the rhexis margin and never goes underneath the anterior capsule. Hence it is easy to work with even small pupils or glaucomatous eyes. Since we don’t have to

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PHACOEMULSIFICATION widen the pupil, there is little likelihood of tearing the sphincter and allowing prostaglandins to leak out and cause inflammation or cystoid macular edema (CME). In this technique we can easily go into even hard nuclei on the first attempt. Soft Cataracts In soft cataracts, the technique is a bit different. We embed the phaco tip and then cut the nucleus as if we are cutting a piece of cake. This should be done 2 to 3 times in the same area so that the cataract gets cut. It is very tough to chop a soft cataract, so this technique helps in splitting the cataract. Topical Anesthesia Cataract Surgery

All our cases are done under topical anesthesia. Four percent Xylocaine drops Fig. 8.14: Stromal hydration are instilled in the eye about 3 time’s 10 to15 minutes before surgery. No intracameral anesthesia is used. It is not advisable to use Xylocaine drops while operating. This can damage the epithelium and create more trouble in visualization. No stitches and no pad are applied. This is called the—no injection, no stitch, no pad cataract surgery technique. No Anesthesia Cataract Surgery We had been wondering whether any topical anesthesia is required or not. So we then operated patients without any anesthesia. In these patients no Xylocaine drops were instilled. The patients did not have any pain. It sounds funny because we have been taught from the beginning that we should apply Xylocaine. This is possible because we do not touch the conjunctiva or sclera. We never use any one-tooth forceps to stabilize the eye. Instead what we use is a straight rod which is passed inside the eye to stabilize it when we are performing rhexis, etc. The anterior chamber should be well maintained and the amount of ultrasound power used very less. If you tend to use the techniques like trenching then the ultrasound power generated is high, which in turn generates heat. This causes pain to the patient. If you follow these rules one can perform No Anesthesia Cataract Surgery. It is not necessary to do this, as there is no harm in instilling some drops of Xylocaine in the eye. The point is that there is always a discussion

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which anesthetic drop to use. It does not matter. The technique, which you perform, should not produce pain to the patient. CONCLUSION As in any other field, progress is inevitable in ophthalmology more so in cataract surgery. We have started to look on cataract surgery as a craft and should constantly try to improve our craft and become better everyday. By this, we will be able to provide good vision to more people than any one dared dream a few decades ago. It also goes without saying that we are and will be forever grateful to all our patients because without their faith, we would never have had the courage to proceed. Keeping this in mind, we hope and wish that the effectiveness and the advantages of this “Karate Chop Technique” be realized and practised, thereby making the technique of phacoemulsification safer and easier providing good visual outcome and patient recovery.

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Keiki R Mehta Cyres K Mehta

Clear Corneal Cataract Surgery

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INTRODUCTION Clear corneal cataract incisions are becoming very popular for cataract extraction and IOL implantation throughout the world. Using clear corneal incisions, with the concomitant use of intracameral anesthesia, cataract surgery has now been refined to such an extraordinary level, that it has reached the stage of virtually immediate, visual rehabilitation. Perhaps the greatest advantage of clear corneal incisions is the tremendous safety with relative astigmatic neutrality, coupled with exceptional results. The limbal location for cataract surgery has been in use from time immemorial. In India, couching has been an established technique, which, is still in use in inaccessible parts. Jaques Daviel in 1745 utilized clear corneal incisions in his cataract surgery technique. Albrecht Von Graefe in 1750 developed a clear corneal knife and developed a very successful corneal incision technique that became famous as the “Graefe section”. Kratz in 1980, was the first phacoemulsification surgeon to go more posterior , making scleral incisions commencing far back and tunneling forwards with a view to increase appositional surface, which would enhance wound healing and thus reduce surgically induced astigmatism. Gerard and Hoffman in 1984 were the first to name the posterior incision as “the corneal tunnel”. Moreover, they were the first to make a point of entering the anterior chamber through the cornea, creating for the first time a corneal shelf. Maloney in 1988, popularized this particular corneal shelf, which in the earlier days was made purely as a means of preventing iris prolapse. In 1989 MacFarland recognized the advantages of implantation of foldable lenses with the self-sealing incisions, but it was Ernst in 1990 who recognized that this long scleral entry, with a tunnel configuration, coupled with a corneal shelf acted as a one-way valve and

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thus explained the mechanism for self-apposition and changed the name from corneal shelf to posterior corneal lip. Howard Fine in 1992 presented his self-sealing temporal corneal tunnel incision at the annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS) and from that time onwards it has become an extremely popular technique. Giving appropriate credit to many surgeons all over the world who had favored corneal incisions for cataract surgery, the leaders in this field were Harms and Mackinson in Germany in 1967, Charles Elm in 1968, Troutman in 1973. In Japan, one of the leading proponents was Kimiya Shimuju. In a recent survey in Eye World magazine, 60 percent of the American surgeons surveyed utilize self-sealing clear corneal cataract incisions for phacoemulsification and foldable IOL implantation. It is anticipated the number will perhaps double by the next year. CONTROVERSIES REGARDING CLEAR CORNEAL INCISIONS The indications for clear corneal cataract surgery have expanded significantly since the last few years. Initially the indications were limited to those patients on anticoagulants, with blood dyscrasias, patients with cicatrizing diseases such as ocular pemphigoid, or Stevens Johnson syndrome. However, the greatest advantage of the clear corneal incision has been the ability to do surgery with topical anesthesia. With the ability to avoid an injection into the orbit, with all its attendant risks, or utilization of intravenous medication in patients with cardiovascular insufficiency, or enhanced risk in patients with general debility, clear corneal cataract surgery became automatically the ideal technique. Another big advantage of clear corneal incisions was that the clear corneal incision technique is topographically astigmatism neutral. With inherent astigmatic neutrality, the predictability of additional astigmatic and cylindrical reducing techniques like arcuate or limbal keratotomy became more predictably effective. The advent of phakic IOL as well as multifocal IOLs has led to stress to gain accuracy not only with the basic power, but to avoid any further development of astigmatism and reduce significantly, if not eliminate astigmatism. Advantages of the temporal clear corneal incision include better preservation of pre-existing corneal configuration, with better preservation of the limbal zone at the 12 O’clock position for future filtering surgery. In cases with tight lids where the exposure is poor, the temporal incision makes life much easier for the surgeon. In addition, drainage from the temporal site is easier as the fluid trickles out from the naturally draining side zone. A fair quantum of controversy regarding the clear corneal incisions was the major concern of increased incidence of endophthalmitis secondary to delayed chamber reformation. It was felt that poor wound healing enhanced the possibility of late postoperative infection. Fortunately, a significant number of very meticulous studies have shown that with a well-designed trapdoor incision, a clear corneal incision, be it placed vertically or temporally does not leak, and thus does not in any way

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enhance the risks. On the other hand, the relative simplicity, the superb clarity the next day and the quiet eye far outweigh any inconvenience involved. CLASSIFICATION OF CORNEAL TUNNEL INCISIONS (after Fine et al) Location • Corneal tunnel incision—entry posterior to limbus, exit at the cornea-scleral junction • Corneal tunnel incision—entry just posterior to limbus, exit in clear cornea. • Clear corneal tunnel incision—entry and exit in the clear cornea. Architecture • Single plane no groove • Shallow groove < 400 microns • Deep groove > 400 microns Size and Planar Configuration • Single-plane incision 2.5 by 1.5 mm rectangular tunnel • Two-plane incision 2.5 by 1.5 mm rectangular tunnel • Three-plane incision 2.5 by 1.5 mm rectangular tunnel plus a perpendicular arcuate component. STRENGTH OF CLEAR CORNEAL INCISIONS VERSUS LIMBAL OR SCLERAL INCISIONS Paul Ernst in 1994, demonstrated that rectangular clear corneal incisions in animal models show higher resistance to external deformation utilizing pinpoint pressure as compared to square limbal incisions. The question of stability of the corneal tunnel has been the challenge of pinpoint pressure. The concept has been that whether cataract wound strength should be evaluated by challenging one’s incision using a pinpoint pressure on the posterior lip of the incision. Howard Fine and many other surgeons have demonstrated that it is not a correct test, as it is very unlikely that the patient would challenge his or her own wound strength by pressing with so fine an instrument as to pinpoint the exact site of pressure, which may leak. It is more appropriate to check the challenge with a blunt hook, which closely resembles the pressure, induced by a fingertip or knuckle, which is the most likely way the patient, would exert pressure. It is very unlikely that even a small percentage of incisions would leak spontaneously with blunt pressure (Fig. 9.1). Questions have been raised regarding the relative safety of clear corneal incision versus a limbal-based corneal incision. Though, in theory, the limbal-based corneal incision would heal faster, and have a stronger ability to prevent leakage, the corneal incision gives excellent stability against leakage, and against accidental pressure.The one big disadvantage of the limbal-based corneal incision is the greater likelihood of ballooning of the conjunctiva, either at the site of the incision or even sometimes

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Fig. 9.1: Side port being made with 1.2 mm MVR blade

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Fig. 9.2: Clear corneal tunnel being prepared with corneal substance

the complete conjunctiva, billowing forwards, making visualization of the anterior chamber structures during the surgical procedure more difficult. A point of caution Park in 1997 has demonstrated that violation of the glaucoma bleb could threaten the integrity, not only of pre-existing filtering bleb but could also make the zone very amenable to subsequent infection. In addition, there is always likelihood that even a minor trauma like a hard rub to the eye could lead to a small hemorrhage. TECHNIQUES Fine et al in 1992 described the first self-sealing corneal tunnel incision for small incision cataract surgery utilizing a 3.00 mm diamond knife. The technique utilized was a two-plane incision. The first incision was performed perpendicular to the plane of the cornea (Fig. 9.2). The depth of the incision is kept at roughly 200 microns. Though ideally done with a calibrated diamond knife, it is more often, than not, done using the unguarded edge of the diamond knife, with the incision being made a little deeper than a superficial scratch. In doing the second plane, the knife enters deep into the primary incision and then continues in a plane parallel to the corneal plane, forming the cleavage in the corneal stroma. In practice it is simple to do, if the operating surgeon places the flat of the diamond blade, opposed to the conjunctiva, and then enters via the primary incision made. It gives a virtually perfect placement in the stromal zone (Fig. 9.3). The tip of the diamond knife after a 2 mm tunnel is constructed, is then allowed to “dimple” the edge of the Descemet’s, and is then simply pushed forward in the same plane, to achieve a cut in a straightline configuration (Fig. 9.4). Alternatively, the surgeon can use a round disk knife to dissect open a shallow stromal tunnel of the required length and then enter the chamber with the knife. Caution should be used in not entering the chamber with the rounded disk knife as it does not give a straight line cut and will compromise the valve function of the incision.

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Fig. 9.3: Tip entered into anterior chamber. Tunnel complete

Fig. 9.4: If required the tip can be dimpled down prior insertion into anterior chamber

Paul Ernst has clearly demonstrated that to be astigmatically neutral the incision should be squared. (i.e. the length and the width of the tunnel should be equal). Williamson in 1993 was the first to utilize a 300 to 400 microns primary clear corneal incision. Rationale for the Williamson incision was that a thicker external edge to the roof of the tunnel had a less likelihood of tearing. Langerman in 1994 described the single hinge incision in which the primary incision was made vertically in the cornea for a depth of ¾ of the cornea (400 microns) with the calibrated diamond knife. Subsequently, half way through the depth of the incision a horizontal groove is made in the stroma. The knife is then passed parallel to the corneal plane for a length of 2.00 mm, is dipped down to dimple the Descemet’s membrane and penetrates into the anterior chamber. Langerman felt that this initial “hinge” gave total protection towards accidental leakage of aqueous by pressure on the posterior flange of the incision. This technique led to an improved resistance for leakage from the incisional edges by the application of external pressure leading to deformation. New Blade Technologies The Fine Tri-diamond knife was developed with Mastel so that the entry incision into the cornea and exit from the cornea into the anterior chamber could be made in an extremely sharp thin line without a necessity to depress the tip of the knife down which often results in a tendency for tearing of tissue or scrolling of the Descemet’s membrane. It also makes for a superb self-sealing valve. Rhein Medical developed a 3-D blade of 2.8 mm in width. This blade has differential slopes on the anterior and posterior surfaces, so that the forces of the tissues exerted along the blade will automatically allow the blade to “flow” in the plane of the cornea with no risk of an early entry nor of an inadvertent anterior escape. One simply places the tip of the blade where one desires the external incision. The blade is then pushed in the plane of the cornea with no attempt to applanate the cornea or attempt to enter the eye by dimpling. Perfect incision can be made rapidly, and more importantly, reproducibly produced.

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CLEAR CORNEAL INCISIONS AND ASTIGMATISM One has to clearly understand the rationale of clear corneal incisions • Excellent access to the anterior chamber for proper rhexis performance and access to the cataract and for IOL placement. • Virtually bloodless incision • Enables the formation of a self-sealing incision, resistant to deformation or leakage. • Variable incision architecture to reduce or eliminate pre-existing astigmatism • Faster physical rehabilitation of the patient. Most surgeons will permit immediate postoperative bending over by the patients or even strenuous physical activity without the risk of wound disruption. • Being an anastigmatic incision, the refractive stability is almost perfect enabling additional reading spectacles to be prescribed in 4 days time. • A much quieter eye, with faster healing, virtually no irritation or redness and no “flag” signs of inflammation. TOPOGRAPHIC CONTROL OF CORNEAL ASTIGMATISM Astigmatism has always been an integral part of cataract surgery. Intracapsular cataract extraction (ICCE) is still popular in many parts of the world especially in Asia, Middle East and Africa. The ICCE technique generally utilized the Graefe knife or scissor based, 180-degree corneal incision. Subsequent wound closure by suturing with 10/0 nylon usually saddled the poor patient with an exorbitant quantum of variable astigmatism. The shift to extracapsular cataract surgery (ECCE) did little to reduce the astigmatism, as invariably a two plane or a three plane, large implant had to be inserted. It was the advent of phacoemulsification that has made the surgeon, and the patient, appreciate the advantages of small incision surgery and apply the concept in an endeavor to reduce astigmatism still further. The greatest advantage of clear corneal < 3.00 mm (also termed sub-three) incision, was that it was literally an astigmatic neutral incision. Evaluating corneal changes utilizing the computerized corneal topographer has significantly improved the understanding of how these incisions work and what has to be done to reduce their astigmatic tendencies. Ideally, corneal topography should be done in all cases in an effort to evaluate the astigmatic component and the resting status of the cornea. In order to understand the effect of clear corneal sutureless incisions, one has to comprehend that the shape of the corneal dome is derived partly from lamellar collagen bundles and the relative elasticity of the corneal tissue. Trauma induced to a cornea, be it an injury or even simply, surgery, affects the regularity of the corneal surface. As the lesions heal, alterations are induced to the corneal shape. It must however be clearly appreciated that while a corneal incision made of 2.8 mm size will induce no topographically demonstratable astigmatic changes whatsoever, one of 4.00 mm or 5.00 mm will induce against-the-rule (ART) astigmatism, more so, if the incisions are not properly constructed.

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It is perfectly feasible to combine phacoemulsification and astigmatic surgery on the table. However this is acceptable only provided, the cornea is quite regular (< 2.00 D astigmatism) and the maximum width of the incision to be utilized is 3.00 mm, or smaller. If the astigmatic component is more or if one is going to be enhancing the incision to 4.00 or more, it makes more sense to do it as a twostep procedure. Do phaco as a primary procedure, allow the cornea to stabilize postoperatively, and only then after doing a computerized corneal topography , plan and complete the astigmatic procedure. CONCLUSION Clinically, clear corneal incisions have now become the most popular option for cataract extraction IOL implantation throughout the world. Spearheaded by phacoemulsification and the now sub-three (< 3.00 mm ) sized incisions, significant improvements in surgical techniques have resulted in a keen appreciation of astigmatism, how it is induced and what can be done to reduce, if not eliminate it entirely. Being naturally anastigmatic, phacoemulsification incisions serve as an ideal background datum to achieve a zero refractive status, and at the same time, in managing residual astigmatism, obviate the necessity for complex calculations. Clear corneal incisions have had an outstanding record of safety with exceptional cosmetic outcome and should increase in popularity with time. FURTHER READING 1. Kirk S, Burde RLM, Waltman SRL: Minimizing corneal endothelium damage due to intraocular lens contact. Invest Ophthalmol Vis Sci 16:1053, 1977. 2. Ernst PH, Kiessling LA, Lavery KT: Relative strength of cataract incision in cadaver eyes. J Cataract Refract Surg 17(suppl):668-71, 1991. 3. Ernst PH, Lavery KT, Kiessling LA: Relative strengths of scleral corneal and clear corneal incisions constructed in cadaver eyes. J Cataract Refract Surg 21:39-42, 1994. 4. Ernst PH, Neuhann T: Posterior limbal incision. J Cataract Refract Surg 22:78-84, 1996. 5. Ernst PH: The corneal lip tunnel incision. J Cataract Refract Surg 20:154-57, 1994. 6. Ernst PH: The self-sealing sutureless wound: Engineering aspects and experimental studies. In Gills JP, Martin RG, Sanders DR (Eds): Sutureless Cataract Surgery. SLACK Inc: Thorofare 23-39, 1992. 7. Edelhauser HF, Gonnering R, Van Horn DL: Intraocular irrigating solutions—a comparative study of BSS plus and lactated Ringer’s solutions. Arch Ophthalmol 96:516-20, 1978. 8. Edelhauser HF, Van Horn DL, Schultz RO et al: Comparative toxicity of intraocular irrigating solutions on the corneal endothelium. Am J Ophthalmol 81:473-81, 1976. 9. Edelhauser HF, Van Horn DL, Hynduiuk RA et al: Intraocular irrigating solutions—their effect on the corneal endothelium. Arch Ophthalmol 93:648-57, 1975. 10. Edelhauser HF, Rosenfeld SI, Waltman SR et al: Discussion of comparison of intraocular irrigating solutions in pars plana vitrectomy. Ophthalmology 93:114-15, 1986. 11. Fine IH, Finchman RA, Grabow HB (Eds): Clear Corneal Cataract Surgery and Topical Anesthesia Slack Inc: Thorofare 1993 12. Fine IH: The Rhein 3-D diamond knife. Eye World 1:2-24, 1996. 13. Fine IH, Fichman RA, Grabow HB: Clear Corneal Cataract Surgery and Topical Anesthesia Slack Inc: Thorofare 1993. 14. Fine IH: Architecture and construction of a self-sealing incision for cataract surgery. J Cataract Refract Surg 17(suppl): 672-76, 1991. 15. Fine IH: Cortical cleaving hydrodissection. J Cataract Refract Surg 18:508-12, 1992.

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16. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-66,1986. 17. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60, 1989. 18. Mehta KR: Endocapsular phacoemulsification and posterior chamber IOL implantation. All India Ophthl Soc Proc 217-20, 1989. 19. Keiki R Mehta: Post-cataract astigmatism—a comparison between phacoemulsification and ECCE procedure—cataract with and without intraocular implantation. All India Ophthl Soc Proc 226-29, 1989. 20. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in paediatric cataracts. All India Ophthl Soc Proc 207-10, 1995. 21. Mehta KR: The clear corneal phacoemulsification with injectable silicone lenses. All India Ophthl Soc Proc 218-22, 1995. 22. Mehta KR: The new shelve and shear technique for simplified phacoemulsification. All India Ophthl Soc Proc 222-24, 1995. 23. Mehta KR: Posterior chamber implantation. All India Ophthl Soc Proc 143-44, 1990. 24. Mehta KR: YAG Laser damage to intraocular implants—an evaluation. All India Ophthl Soc Proc 14750, 1990. 25. Mehta KR: Phacoemulsification—is it the true III world answer for eye camps. All India Ophthl Soc Proc 301-03, 1990. 26. Mehta KR: An analysis of causative faction leading to eye strain caused by computer monitor screens. All India Ophthl Soc Proc 334-36, 1990. 27. Mehta KR: Single stitch elliptical funnel incision for cataract surgery. All India Ophthl Soc Proc 25354, 1991. 28. Mehta KR: Bifocal intraocular implants—a functional evaluation based on 425 cases. All India Ophthl Soc Proc 271-74, 1991. 29. Mehta KR: Phacoemulsification with flexible PC IOL—is it really a step forward? All India Ophthl Soc Proc 287-88, 1991. 30. Mehta KR: The New Phaco cleave technique for hard cataracts. J Intraocular Implant and Refractive Society India, 1(1): 74-75, 1996. 31. Mehta KR, Sathe, SN, Karyekar SD: The new soft intraocular lens implant. Am Intra-Ocular Implant Society J 4(4):200-205, 1978. 32. Mehta KR, Sathe SN, Karyekar SD: New soft posterior chamber implant. X Congress of the AsiaPacific Academy of Ophthalmology. New Delhi,1985. 33. Keiki R Mehta: When not to do an anterior chamber implant. All India Ophthl Soc Proc 164 -165,1986. 34. Mehta KR: Mehta Tangential Chop (MTC) technique for phacoemulsification. All India Ophthl Soc Proc (Chandigarh) 1996. 35. Mehta KR: Phaco-levitation—a peaceful way. All India Ophthl Soc Proc (Chandigarh) 1996. 36. Mehta KR: Comparison of centration stability and capsular response to AcrySoft and silicone S130 lenses. All India Ophthl Soc Proc 1998. 37. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference 1997. 38. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 39. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 40. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

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Shashi Kapoor

Capsulorrhexis (CCC): A Beginner’s Guide

10

INTRODUCTION Continuous curvilinear capsulorrhexis (CCC) is one of the revolutionary innovations of modern cataract surgery. It was presented to the ophthalmic, surgical community in 1985 and 1986 by Fercho, Graether, Gimbel, and Neuhann. These ophthalmologists were able to use and appreciate CCC because they had developed methods for performing phacoemulsification totally within the capsular bag, i.e. they were not using an iris plane approach in which the superior pole of the cataract is tipped superiorly out of the bag for tip access. Terminology CCC—continuous, circular, capsulorrhexis. The border does not need to be “circular”, but may be ovoid or elliptic. Hence, the more generic word “curvilinear” has replaced “circular”, leaving the abbreviation the same—CCC. Anatomy of Lens Capsule The posterior zonular fibers are inserted 1.0 to 1.5 mm from the equator, while the anterior zonular fibers are attached approximately 2.0 mm from the equator. Since the diameter of the adult crystalline lens is 9.5 to 10.0 mm, the “zonulefree” area, on the anterior capsule is approximately, 6.0 mm in diameter only. It is therefore ideal to create a tear limited to the zonule-free area, preferably slightly inside the zonular frontier, as zonular fibers have been observed more centrally than has previously been considered.

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Technique Prerequisites Absence of positive pressure— facilitated by use of viscoelastic agents, air, irrigation, or a “closedchamber” technique, where a bent needle, used to perform the CCC, perforates the preplaced incision, before any other entry is made into the anterior chamber. Instruments Cystotomes, bent needles or forceps, can all be used effectively. Existing ultrasonic or thermal devices, are not believed to offer any advantages. Initiation of Tear Beginning of CCC peripherally, carries a greater liability than beginning centrally. With the initial cuts made centrally, radial stress vectors across the anterior capsule are interrupted, resulting in less tendency for the tear to extend towards the equator. It is always easier to spiral the initial tear out to enlarge a capsulotomy, than it is to pull a peripheral tear back towards the center. Technique Using a bent needle, of 23 G to 25 G, a perforation is made in the Figs 10.1 A to C: Continuous curvilinear capsulorrhexis center of the anterior capsule. By (CCC): (A) central puncture with cystotome and progression extending this with the sharp edge of tear to the 3.0 O’clock position, (B) the curvilinear tear is continued counterclockwise with the capsular flap folded of the needle, a horizontal incision over itself, and (C) the progressing tear is blended at 3.0 is made (Fig. 10.1A). The tip of the O’clock with the cystotome having re-engaged the ventral needle is now used to redirect the surface of the capsule for optimum control (Gimbel) tear in a counterclockwise direction. This creates a flap with a smooth curve as it is beginning. The flap is then pulled along in a circular manner by means of gentle traction with the needle tip. If the tear starts to extend peripherally, it is usually the result of positive vitreous pressure

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and can be counteracted by reinflating the anterior chamber with viscoelastic. A light touch is needed, because if one presses too hard on the flap, it creates a responding increase in vitreous pressure, which forces the tear outward. As the flap progresses, large amounts of capsular folds will present and must be pushed out of the way, so that one can visualize the exact point at which to place the tip of the needle (Fig. 10.1C). When completing the CCC, one should overlap the tear such that the last part of the tear joints the first part from the outside towards the center, thus resulting in a continuous edge. If the overlap is created from the center towards the outside, it will result in a small triangular flap, with a tendency to tear towards the equator or beyond. The best control of the progressing tear is achieved by grasping the developing capsular flap, with the desired instrument close to where the capsule is tearing at the time. The direction of the tear can be controlled by the position of the instrument. Placing the tip of the instrument a little peripheral to the advancing tear, will direct it outwards. Placing it a bit central to the tear will direct it towards the center. Tear patterns may vary, and progress clockwise or counterclockwise. There are cases however, when no form of CCC may be achieved. These include capsules that are heavily fibrosed and shrunken, as in certain congenital, secondary, and traumatic cataracts. In these patients, a continuous, curvilinear opening often still may be achieved by using a capsule scissors to cut through the fibrosed part of the anterior capsule. In the nonfibrosed area, the smooth edge border of the CCC is achieved by the usual methods. A Kraff-Utrata forceps can be used to perform CCC. The initial puncture in the anterior capsule is made with a bent needle, (or with the forceps itself, if the tips of the forceps are sharp enough), and the rest of the CCC is continued with the forceps. Using the forceps requires a larger opening into the anterior chamber as compared to a bent needle, and viscoelastic is usually necessary. Two-staged CCC In this procedure, the original capsulotomy is just large enough to admit the smaller endocapsular phaco probe and a second instrument for lens manipulation. After the

Figs 10.2A and B: Two-staged continuous curvilinear capsulorrhexis (CCC)

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lens material is removed a small initial opening is converted to a larger one, of the desired diameter, while still maintaining the continuous tear edge. The second capsulotomy is started with a tangential snip on one side of the opening with a Vannas scissors (Figs 10.2A and B). This requires a viscoelastic agent in the anterior chamber and lens capsule. It is important to prevent the side of the capsule opening from folding over or under at the scissors tip so as to prevent a V-cut. Also, the snip is not taken to the scissors point, because the point may create an irregularity in the line of the cut. Such a notched cut destroys the integrity of the continuous tear. Once the tangential cut is successfully achieved, the second continuous tear is then extended, using Utrata forceps to complete a larger circle, which is centered in the pupil, and is of the desired diameter. The forceps enlarges the original capsulotomy by removing a strip or ribbon of additional capsule. Two-staged CCC is Particularly Useful • In patients with small pupils, when an originally small CCC requires subsequent conversion to a larger CCC. • When the original CCC is made inadvertently small. • For corneal endothelial protection in intercapsular and endocapsular cataract extraction. A similar technique may be used in blunting or turning back, short inadvertent tears of the anterior capsular border. Posterior CCC (PCCC) Posterior CCC uses the principle of CCC and is used to advantage, when a small linear or triangular tear inadvertently occurs in the posterior capsule, in order to convert it into a smooth CCC that is resistant to radial extension. The PCCC is accomplished just as one does an anterior CCC. The size of the PCCC is kept as small as possible to preserve the maximum support by the posterior capsule. Equatorial capsular tears, posterior capsule tears near the equator or with extensions to the equator are not suitable for PCCC. PCCC may also be used, for making primary posterior capsulectomies, in removing posterior plaques, or to blunt, small extending tears with posterior continuous. Intumescent Cataracts and CCC Intumescent cataracts are a special problem for any form of capsulotomy, especially CCC. The internal lens pressure simply splits any rent towards the equator. A useful technique in such cases, is to decompress the lens by first aspirating some lens cortex. Another difficulty is the poor visualization of the tearing edge, in milky white cataracts, where there is no red reflex. In such instances, Lee has found it extremely useful to perform CCC under air. The distortion of the tearing capsule under an air-lens interface is apparently, exceptionally clear.

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Advantages of CCC There are several advantages of CCC: • In-situ phacoemulsification is facilitated, and the ultrasonic turbulence is contained within the lens capsule. • IOL implantation and verification in the bag is greatly facilitated because of the smooth-edge visible rim. • IOL rotation with no chance of decentration caused by loops coming out of the bag is allowed. • No capsular tags or V-shaped tears are left that can extend into the posterior capsule, under even minimal, mechanical stress. • A diaphragm quality of the capsule for sulcus placed lenses is maintained or preserved in the event of a ruptured posterior capsule. • Chances of posterior synechiae are reduced. • In-the-bag IOL implantation in the very elastic capsule of children is facilitated. ECCE and CCC Most surgeons recommend one or two “relaxing incisions” in the CCC, prior to nuclear expression in extracapsular cataract extraction (ECCE). The relaxing incision helps prevent untoward complications as zonular tears, vitreous loss, unintended ICCE, or even prolapse of lens into the vitreous cavity. Hydrodissection, hydrodelineation, and hydroexpression techniques are useful adjuncts, when using CCC along with ECCE. Complications of CCC These include: • Shrinkage of anterior capsular opening • Capsular bag hyperdistention • Epithelial cell hyperproliferation on the posterior capsule. CAPSULAR CONTRACTION SYNDROME Capsular contraction syndrome is seen after ECCE using can-opener capsulotomy or CCC. While rarely with can-opener capsulotomies, with anterior radial capsular tears, it is relatively frequent with CCC. The syndrome consists of an exaggerated reduction in the anterior capsulotomy opening and equatorial capsular bag diameter. This may also

Fig. 10.3: (Davison) Capsular contraction syndrome with capsulorrhexis opening displaced inferiorly and open to only 2.0 mm several months after surger y in eye with pseudoexfoliation

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lead to a malposition of the IOL. These effects seem more exaggerated in small CCC openings and the older patient (Figs 10.3 to 10.6). It is due to capsular bag contraction from fibrous dysplasia of residual lens epithelial cells, countered by relatively unopposed weak zonular support. This is particularly seen, in pseudoexfoliation, advanced age, and in association with uveitis, pars planitis, and myotonic muscular dystrophy. Fig. 10.4: (Davison) Excessive capsular contraction has shrunk the capsulorrhexis opening to approximately 2.0 mm. The opening is decentered as is the silicone optic and the capsular bag; so the zonular fibers are visible below. Pseudoexfoliative material can be seen on the fibers

Role of IOL Material

Hayashi et al showed the reduction in the area of anterior capsule opening at various postoperative intervals after continuous capsulorrhexis and compared any differences in the area reduction between polymethylmethacrylate (PMMA), silicone, and soft acrylic IOLs. Figure 10.7 shows retroillumination photographs, which illustrate the typical postoperative changes in the anterior lens capsule of the three optic materials. Figure 10.7 top left, shows an eye after undergoing PMMA IOL implantation. A slight degree of Fig. 10.5: (Hansen) Red reflex of an eye with dense contraction and fibrosis of the anterior capsular fibrosis and well-centered, but anterior capsule opening occurred extensively constricted capsular opening (1.3 mm). Note the radial stress lines and the broad fibrous rim of over the PMMA optic. Figure 10.7, top the circular capsulotomy. The three-piece posterior right, shows an eye after undergoing chamber IOL is completely within the capsular sac and silicone IOL implantation. shows a mild inferotemporal decentration The contraction of the anterior capsule progressed markedly up to 3 months after surgery. The degree of fibrosis in the anterior capsule was also extensive. Figure 10.7, bottom shows an eye after soft acrylic IOL implantation. The anterior capsule contraction was very slight. Surprisingly, no fibrosis in the anterior capsule was evident in some cases in the soft acrylic IOL group. The study clarified that the area of the anterior capsule opening gradually decreased for up to 3 months after surgery. However, after 3 months, the area reduction in the anterior capsule opening showed no further progression. The percentage of the area reduction with the silicone IOL

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Fig. 10.6: (Hansen) Photograph of a case immediately after Nd: YAG laser anterior capsulotomy in a cross pattern, cutting through the fibrous rim of the constricted opening

was greater than that with the polymethylmethacrylate and soft acrylic intraocular lenses. No significant difference was observed between the PMMA and soft acrylic intraocular lenses. Furthermore, although it could not be quantitated in this study, the degree of fibrosis in the anterior capsule was most extensive in the silicone IOL, followed by the PMMA IOL. On the other hand, the anterior capsule fibrosis over the soft acrylic optic was extremely slight.

Prevention Capsular fibrosis is caused by metaplastic lens epithelium. The more epithelium that is left, the greater the potential for capsule contraction. Since twice as much epithelium is removed with a 5.5-mm capsulectomy as with a 4.00-mm capsulectomy,

Fig. 10.7: Retroillumination photographs showing postoperative changes in the anterior lens capsule. (Top left) after a polymethylmethacrylate (PMMA) IOL implantation. A slight degree of contraction and fibrosis in the anterior capsule was observed over the PMMA optic. (Top right) An eye after a silicone IOL implantation. A marked contraction of the anterior capsule opening occurred for up to 3 months. The degree of fibrosis in the anterior capsule was also prominent, especially along the capsulorrhexis edge. (Bottom) An eye after soft acrylic (AcrySof) IOL implantation. The anterior capsule contraction over the soft acrylic optic was very slight. It was surprising that no fibrosis in the anterior capsule was evident

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one should make the larger anterior capsulectomy in vulnerable eyes. The sphincter effect of an intact capsulorrhexis is important in creating significant capsule shrinkage. A can-opener capsulotomy with deliberately created anterior radial capsular defects may be appropriate in lose eyes with zonular weakness. Another influence in maintaining capsular bag size and shape and good functional IOL position is the use of a one-piece, all-PMMA IOL with a relatively firm broad haptic structure. Nishi suggested vacuuming the undersurface of the anterior capsule to significantly reduce the amount and effect of residual lens epithelial cells.

Fig. 10.8: Six anterior YAG capsulotomies are almost not visible, three weeks after creation in a patient with pseudoexfoliation

Fig. 10.9: Same eye as in Figure 10.8 six anterior YAG capsulotomies have been redefined with more YAG separation

Role of Nd:YAG Laser Early anterior radial YAG laser, relaxing capsulotomy helps resolve the ultimate contraction of the anterior capsulectomy opening (Figs 10.8 and 9). These anterior capsulotomies may also reduce the incidence of more rare complications of excessive zonular traction and its sequelae, IOL dislocation and retinal detachment. If capsule contraction is noted, consider YAG laser relaxing anterior capsulotomies at 2 to 3 weeks postoperatively. Active capsular fibrosis and attendant contracture of the anterior capsule and indeed the entire capsular diameter can be influenced with early YAG laser intervention, whereas later intervention may not help really as much. CAPSULAR

BAG

HYPERDISTENTION

“Capsular block” implies fluid hyperdistention of the capsular bag from occlusion of the circular anterior capsule opening by the IOL optic; the resulting anteriorplacement of the optic induces an artificial myopia; the source of the fluid is unclear, although some have suggested that it is retained viscoelastic (Fig. 10.10). Other possibilities include transudation through the lens capsule or exudation from the lens epithelial cells. Capsular block is generally self-limiting and is only associated with capsulorrhexis and IOLs flexible or mobile enough to move forward against the capsule opening; it has not been observed with the traditional can-opener

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Fig. 10.10: (Masket) Schematic representation of the capsular block phenomenon. The highly flexible one-piece lens depicted in this model is bowed forward, the optic portion blocks the capsulorrhexis, and the capsular bag is distended

Fig. 10.11: (Masket) String of pearls observed as the hyperproliferation of lens epithelial cells (Elschnig pearls) surrounding a previously formed Nd: YAG laser posterior capsulotomy

capsulotomy or with one-piece PMMA IOLs. A small Nd:YAG laser opening in the anterior or posterior capsule permanently relieves capsular block. HYPERPROLIFERATION

OF

LENS

EPITHELIAL

CELLS

Hyperproliferation of lens epithelial cells in the form of Elschnig pearls on the central posterior capsule, surrounding a previously made laser capsulotomy, has been reported (Fig. 10.11). The “string of pearls” that forms around the capsulotomy reduces the opening, making the capsulotomy potentially too small to be optically adequate. The pearls appear to form on the anterior hyaloid and capsulotomy edge, using either as scaffolding, and then progress centrally. The epithelial cells surrounding the capsulotomy are dense, but became more sparse peripherally. Perhaps a stimulus to epithelial cell growth is present in the anterior vitreous, since the string of pearls does not form until after the posterior capsule has been opened. The “string of pearls” has only been observed in cases in which the IOL diameter was larger than the anterior CCC. In this situation, the anterior capsule overlaps the IOL edge, and the anterior and posterior capsules cannot fuse in a true Soemmering’s ring because the optic is sandwiched between the capsule leaflets. The reduced effective size of the posterior capsulotomy associated with the hyperproliferation of lens epithelial cells, has required Nd: YAG laser “retreatment” in many patients.

Shrikant Kelkar

Capsulorrhexis: Principles and Advanced Techniques

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CAPSULORRHEXIS

History The problems related to the sulcus implantation of posterior chamber intraocular lenses (PC IOLs) during the period of about 1975 to early 1980s lead to the idea in favor of placing the intraocular lens implant into the capsular bag which lead to a better centration of the implant. The new design of Simcoe loops (modified C loop) improved better centration. However decentration was not uncommon. The analysis of this decentration showed that in spite of the fact that the lenses were in correct endocapsular situation tears of the anterior capsule originated, luxating one loop into the sulcus which was considered a precondition for subsequent decentration. Realizing the above difficulty in the centration of lens the idea of continuous curvilinear capsulorrhexis (CCC) was born. The credit goes to Tobias H Neuhann and his brother Thomas in developing the technique of capsulorrhexis. At the same time totally independent development by Howard Gimbel who was working on the same idea called this technique as “continuous tear capsulotomy”. Finally, Neuhann and Gimbel called their development continuous curvilinear capsulorrhexis which soon gained popularity all over the world. Physics of Capsulorrhexis If we consider a strip of paper to be torn into two pieces it can be done in two ways: one is as shown in Fig. 11.1A—what can be considered as shearing technique or Fig. 11.1B—ripping.

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Figs 11.1A and B: (A) Shows the shearing technique as compared to the ripping technique in (B). Note shearing is a much more controlled technique

Capsulorrhexis with Shearing Capsulorrhexis starts when the cystitome enters point a and proceeds to point b in a radial manner (Fig. 11.1C). At point b the cystotome is pulled in the direction of the arrow to reach point c to create a capsular crack which gets folded over to lie on the top of intact anterior capsule. At the position d the flap is engaged with cystotome or forceps and is pulled in the direction of curved arrow. Figure 11.1D shows the progress of capsulotomy. This flap is a mirror

Figs 11.1C to E: Rhexis by shearing. Note the position of the dot indicates successive placement site for needle rhexis

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Figs 11.1F and G: Capsulorrhexis by ripping technique: Dot indicates point where the tear is held with the forceps

image of the area of capsulorrhexis performed so far and its edges will indicate in which direction the capsulorrhexis will proceed. Figure 11.1E shows one-third of the rhexis completed. Take a note of the point at which the instrument engaged the capsule which has remained 2 to 3 O’clock hours away from the point of (n) shearing. Instead if the instrument was placed to say at point m, an artificial stress line would be created that would compromise the predictability of the direction of shear. In shearing technique the flap must be spread out flat otherwise it would convert the shear to modified rip. Capsulorrhexis with Ripping Figures 11.1F and 11.1G demonstrate the ripping technique. The surgeon must note that the direction of pulling is much more towards the center of the capsule and the flap is engaged by pulling the instrument at a point which is much closer to the tear. The ripping technique has the tendency to extend peripherally. It has been found that ripping techniques are more difficult to control and are more likely to extend peripherally compared to shearing technique. Yet one must know its ability in changing the direction of the tear. Initiation of Capsulorrhexis The capsule can be incised at point a, proceeding to point b. The triangular flap thus created is grasped at point c and drawn in the direction of the arrow in a curvilinear fashion. Shearing forces will be equally acting at point b and d. In Figures 11.1H and I the pulling motion has changed to a curvilinear direction shown by the arrow. Figure 11.1J shows its further progress.

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Figs 11.1H to J: Triangle tear technique of capsulorrhexis

Methods • • • •

Needle technique Forceps technique Capsulostripsis Diathermy capsulotomy

Capsulorrhexis can be performed by number of methods. All these methods give practically the same results. It involves a continuous symmetrical linear opening of the anterior capsule. In order to get good postoperative results capsulorrhexis must satisfy: Site For optical and functional results the capsulotomy must be centered on the pupil which reduces the possibility of irido-capsular-synechial formation. Suitability (for IOL implantation) Since there is a huge range of IOLs available. The surgeon must first choose the lens and perform the capsular opening accordingly.

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Integrity of the zonules In order to avoid damage to zonular fibers the capsulotomy should be performed carefully in the pre-equatorial zones. Aperture The aperture must be wide enough to allow emulsification of the nucleus easily. A large capsular aperture facilitates easy and quick aspiration of the cortical material. At the same time it should not be so wide as to allow the nucleus to prolapse into the anterior chamber during hydrodissection procedure which usually happens in grade I and grade II cataracts and hence between 5 mm and 6 mm is the ideal size of capsulotomy. Shape If we consider the shape of the eyeball as a round clock, the movement while doing the capsulotomy should be like a radiating arm moving in a circular fashion. Similarly the opening should be round. Last but very important aspect is to have continuous margin. The advantages of the continuous margins are: • Correct centration of the lens in the bag. • The edges of the incision are strong and elastic enough and reduce the risk of capsuler rupture extending to the periphery which can happen in a canopener technique. Principles To achieve the above results the surgeon has to keep in mind the following principles: One must keep in mind before proceeding to surgery that any mistake made during this procedure may face subsequent problems. • It is desirable to use high magnification so that surgeon can control every step of the procedure, adjust the sight and width of the incision and avoid traction process as and when possible. • The light beam must be angled to provide good red reflex of the fundus. • The intensity of the microscope light must be sufficient to facilitate clear view of the capsule and the red reflex. • The pupil must be widely dilated which makes it easier for the surgeon to perform capsulotomy; small pupil can bring contact between cystitome and iris. Dilated pupil also facilitates good red reflex. • A deep chamber reduces the risk of endothelial and iris damage hence the depth of the chamber must be maintained during the entire capsulotomy procedure. The high molecular weight viscoelastic substances are the best tools for this. • One should keep in mind the attachment of the zonuler fibers. On the safer side the capsular aperture should not extend more than 3 mm peripherally from the center of the anterior pole of the lens. • The shape and size of the capsulotomy must be planned by the surgeon prior to beginning the capsular aperture. • The entrance of the instrument into the anterior chamber must be well planned. One must keep in mind the anatomical variations of the individual eye like myopia, hypermetropia, etc. Thus it is desirable to have an optimal working

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position with respect to the planes of the anterior capsule and the iris. Correct use of the instrument and the released hands of the surgeon makes the job easier. The forceps or the cystitome must be handled gently and carefully. They must be used on the surface of the capsule with practically no pressure applied on the cataractous lens. The surgeon must avoid touching the iris because every such touch can reduce the size of the pupil. The surgeon must keep in mind that in younger patients the capsule is thin and elastic and the capsulotomy tends to extend easily towards the equator. Any time surgeon anticipates the difficulty he should stop what is being done and inject the viscoelastic substance to deepen the chamber which allows him a greater margin for maneuvers and errors. Advantages of CC Capsulorrhexis Intraoperative Advantages • CCC limits the risk of tears extending to the periphery and to the posterior capsule during surgery especially in young patients. • Hydrodissection becomes safe and easy. • It restricts the intraocular turbulence inside the capsule. • Reduces the stress on the zonules during surgery. • Most important is that it allows easy aspiration of the cortex and does not let any anterior capsular tags get caught into the aspiration port. • It permits the correct positioning of the IOL in the bag because the surgeon has excellent view of capsular rim. Last but the most important is that since the rim is can be stretched even a slightly large lens can also be manipulated with a comparatively small capsular opening. Postoperative Advantages • Due to extensive contact area between the loop of the IOL the anterior capsule the possibility of decentering is reduced. • Not being in contact with the ciliary body pigment dispersion, hyphema and inflammation are reduced. • In the presence of ruptured posterior capsule after doing anterior vitrectomy a large optic diameter lens can be inserted over the anterior capsule. • Since the lens is put in the bag there is no need to use miotics or the need for iridectomy. It also avoids pupillary capture. Difficulties during Rhexis Rhexis Escape In some cases while the procedure of capsulorrhexis is proceeding on the aperture goes on increasing towards the periphery. The moment this happens the surgeon must ensure that the chamber is adequately deep by injecting more viscoelastic

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substance. It is advisable to use a cystotome attached to a viscoelastic syringe so that in case the chamber becomes shallow more viscoelastic can be injected into the chamber immediately. The chamber will deepen and the tendency for the rhexis to extend will be minimized. At this moment the flap should be caught close to the point in the capsule, the surgeon should then extend controlled pressure directed towards the center of the pupil. Alternative to this technique, instead of forceps or needle one can take deeply curved scissors, deepen the anterior chamber with the viscoelastic and cut the capsule with scissors at the escape point and redirect the opening back to the initial route. One can also choose a new point to start rrhexis in another position operating in a counterclockwise direction and try to join to the first rrhexis escape point. In spite of these maneuvers if the rrhexis extends, abandon the idea of continuous capsulorrhexis and continue with can-opener capsulotomy. Capsulorrhexis in Special Cases Pseudoexfoliation The surgeon must be aware that in this condition the capsule is fragile so the opening must be small so that it does not reach the zonules or create traction forces. Such a small opening can subsequently be extended after the insertion of IOL or subsequently by YAG laser. Young Patients In very young patients proper pupillary dilatation is a big problem. In addition reduced scleral rigidity increases the tendency to positive vitreous pressure. This leads to loss of control in the direction of capsulotomy with an increased risk of peripheral escape. In children therefore the initial incision must be small which can be better controlled by forceps than needle. Viscoelastic substances must be kept in hand. Hypermature or Intumescent cataract Capsulotomy can be done easily when the red reflex is seen. In such situations like hypermature cataract there is no red reflex so capsulotomy becomes extremely difficult as there is no perception of the capsular flap. In addition when the cataract is swollen there are more chances of peripheral escape because of the greater tension on the anterior capsule. When the cataract is intumescent, the contents are usually very liquid like milk, it is advisable to let the semiliquid cortex escape through a central incision, this should be removed with I/A and chamber should be filled with viscoelastic substance, the flap must be taken under a high magnification with very high illumination. This is a good indication to use forceps instead of needle. Instead of red reflex illumination it is advisable to use high intensity oblique illumination. Some surgeons prefer air in the anterior chamber instead of viscoelastic substance. It is advisable to use cystitome instead of forceps when the air is injected into the anterior chamber. Black cataracts also pose the same problem. In small pupils it is advisable to use viscoelastic to deepen the anterior chamber. Use of iris hooks or bimanual stretching is also recommended.

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Posterior capsulorrhexis is a linear continuous circular capsulotomy with all the advantages of elasticity, stability and long-term resistance. This procedure is done in children which avoids second surgery or YAG laser. The surgeon proceeds in the same way as in the anterior CCC. The phacoemulsification is carried out, the anterior segment is filled with viscoelastic substance, the bag is also filled with viscoelastic substance. The first step is to perforate the posterior capsule. Viscoelastic is again introduced behind the posterior capsule which can prevent vitreous prolapse. The second step is to carry out posterior CCC with needle or forceps. In some cases when the vitreous prolapses anteriorly, vitrectomy is done. The remaining tyre like capsular residue provides the stable and secure site for IOL fixation. This posterior capsulorrhexis done in pediatric cataract surgery can avoid secondary membrane formation. Disadvantages of CCC The introduction of capsulorrhexis has led to a new problem called capsular shrinkage syndrome or capsular phimosis. This problem is observed more frequently in patients suffering from pseudoexfoliation syndrome, uveitis, retinitis pigmentosa, in combination with polymethylmethacrylate (PMMA) or silicone IOL implantation. All the above mentioned diseases have reduced number of zonular fibers as common observation. Special Techniques • • • •

Fluorescein blue light assisted capsulorrhexis for mature cataract. Staining the capsule with indocyanine green for white cataracts. Trypan blue capsule staining for better visualization in capsulorrhexis. Diathermy capsulotomy.

Trypan Blue Staining When retroillumination is absent, e.g. dense cataract, it is difficult to discriminate the anterior capsule from the underlying lens tissue and capsulorrhexis carries a high risk of radial capsule tears. To overcome this difficulty and better visualization of capsulorrhexis during surgery, one can utilize: (i) use of side illumination, (ii) hemocoloration of the capsule with autologous blood, and (iii) staining the capsule with gentian violet 0.1 percent or methylene blue 1 percent. All these procedures are relatively time consuming and require an adjustment of the surgical technique and may have endothelial toxicity. On the other hand trypan blue stain enables the surgeon to visualize the capsulorrhexis in the absence of red reflex and does not affect the endothelium. Before injecting the dye anterior chamber is injected with air, removing the aqueous through the cannula. Trypan blue, 0.1 ml in a conccentration of 0.1 percent in

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phosphate buffered sodium chloride is applied to the anterior capsule. After few seconds anterior chamber (AC) is thoroughly irrigated, viscoelastic substance is injected into the AC (Fig. 11.1K). Because of the blue stain the outline of the capsulorrhexis is easily visible. There is an additional benefit that the peripheral anterior capsule ring remains stained and clearly visible during phacoemulsification. Diathermy Capsulotomy In order to overcome the difficulty in doing capsulorrhexis under circumstances such as mature 11.1K: The edges of the rhexis cataract and absence of red reflex, many surgeons Fig. can be stained with trypan blue for better use diathermy capsulotomy. One must keep in visibility mind that some fundamental research from Denmark showed that the extensibility of the capsule edge after diathermy capsulotomy was reduced to half than that of the CCC technique as done by needle or forceps. It was also noticed that the breaking force required to break the diathermy capsulotomy was one-fifth of that required to break the CCC edge. So, the surgeon must keep in mind the risk of inadvertent capsule opening subsequently by tearing during phacoemulsification or on implantation of IOL. CONCLUSION Every surgeon dreams to provide greatest degree of stability of vision to his or her patients. In other words, the surgeon tries to restore the patient’s vision very close to the normal healthy eye without glasses. The new technique of CCC has introduced a biggest breakthrough in performing small incision or phaco surgery. The most important advantage of continuous capsulorrhexis is that it holds the nucleus down in the bag during phacoemulsification surgery. It makes the surgeon keep the instrument tip in the bag and work on the nucleus. The second advantage is, it helps to maintain intact capsular bag. The circular opening into the anterior capsule opens the window over the nucleus. The structural rigidity and integrity of the capsular bag are almost identical to a completely intact bag. In the can-opener technique, the purpose was to permit the nucleus to get out of the bag while CCC holds the nucleus inside. The principle of capsulorrhexis is well established now and its technical performance is being refined and advanced everyday. Capsulorrhexis is a fundamental surgical principle. These days the ophthalmic instrument manufacturing companies are bringing out many tools for the maximum comfort of the individual surgeon. Stability of the capsular bag and centration of IOL by this technique make emmetropia possible.

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Keiki R Mehta Cyres K Mehta

Hydrodissection and Hydrodelineation

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HYDRODISSECTION Hydrodissection is the creation of a cleavage plane between the nucleus and the cortex. It can also be defined as the separation, by a fluid dissecting wave, of the nucleus from the external cortex adhering to the capsule. It is important to appreciate that the cleavage plane is not between the capsule and the cortex. If that were so, then there would never be any need to do cortical aspiration. Hydrodissection is a very important step for endocapsular phacoemulsification. Its biggest advantage is that it permits free maneuvers on the nucleus in the bag without, in any way transgressing on the safety of the capsule. It must be clearly noted that effective and safe hydrodissection can only be done after a good rhexis. It is unsafe to do hydrodissection in a can-opener capsulotomy, or if the rhexis has, inadvertently, run away into the periphery. Injecting fluid at this time will cause the tear to spread backwards. Hydrodissection Technique The technique involves injecting a small amount of fluid (Ringer lactate or BSS) under the anterior capsule with a fine blunt cannula connected to a 3.00 ml syringe. Because of the fluid pressure and the dissecting ability of the fluid to take the path of least resistance, the fluid separates the cortex and the epinucleus and only partly between the capsule and the cortex. During the hydrodissection, the fluid wave can be seen clearly (unless it is a very hard cataract or an opaque one) to separate the cortex from the nucleus and is indicative of a successful hydrodissection. More hydrodissection is usually carried out in three sites commencing with the 4.00 O’clock position (Fig. 12.1) followed by the 2.00 O’clock position (Fig.12.2) and finally followed

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Fig. 12.1: Hydrodissection at 8 O’clock position

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Fig. 12.2: Hydrodissection at 2 O’ clock position

by hydrodissection at 8.00 O’clock position. It is important that small aliquots of fluid be utilized, as excess fluid especially in a hard brown cataract is liable to balloon the capsule posterior, rather than spreading as a wave, and may, if more fluidic pressure is applied, rupture the capsule. It is important to visualize while injecting the fluid diffusion wave. The ideal syringe is a 3.00 ml Luer-Lok, plastic, disposable, Teflon-coated or siliconized. This type of a syringe permits a better control, prevents too much pressure from being applied, the plunger moves very smoothly, and does not stick. Too thin a cannula, (ideal is 24-26 G, flat cannula), even if it is blunt is liable to puncture the capsule if accidentally inserted too far into the periphery. Also a thin cannula permits the fluid to emerge in a sharp jet, at high velocity, which is not required. The one way to be sure the hydrodissection is complete is to check whether the nucleus rotates freely in the bag. The ideal technique of cannula placement for effective hydrodissection is to place the cannula just within the capsulorrhexis edge, slightly tenting it or lifting it upwards. This technique termed as cortical cleaning hydrodissection was originally conceived by Dr Howard Fine. Injecting the fluid along the rhexis edge permits the fluid wave, literally to shear close to the capsule thus, significantly diminishing the quantum of cortical remnants which will need to be aspirated after the primary nucleus is removed by phacoemulsification. In all cases hydrodissection should be followed by mechanical rotation (Fig. 12.3) of the nucleus to be sure that the nucleus rotates freely. Rotation confirms that all the adhesions between the epinucleus and the cortex have been broken. It is important to appreciate that if the lens does not rotate freely one must do hydrodissection again, till smooth rotation is achieved. It is important that after every injection of fluid the lens should be gently pressed backwards. This technique is termed as compression hydrodissection, and works by causing the fluid to disperse and spread out as a flat lamellar zone at the back of the nucleus and thereby enhance the hydrodissection. This technique should be conducted gently following each injection of fluid under the capsular flap. Compression hydrodissection thus, decompresses a filled capsular bag, and at the same time hydrodissects or shears off any adhesions.

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Fig. 12.3: Rotation following hydrodissection

Fig. 12.4: Viscodissection to permit the lens to rotate vertically prior phacoemulsificaiton

Viscohydrodissection The parameters change radically when a viscous material (Healon, Provisc, Viscoat or hydroxypropylmethylcellulose–HPMC) is used. Since it takes much more force to inject, one has to be totally sure of the quantity injected; otherwise rupture of the posterior capsule becomes inevitable. In addition, the viscous fluid will force the iris-lens diaphragm forwards, shallowing the anterior chamber, to almost a mere chink. The fluid stays back as it is too viscous to escape from the sides of the 22 G opening normally used for the hydrodissection cannula (Fig. 12.4). Though it is easier to commence, fluid wave is rarely seen unless it is a very immature cataract. In a hydrodissected nucleus with an adequate sized capsulorrhexis, it tends to push the nucleus forwards and prolapse it out of the rhexis opening. The authors utilize viscodissection only after hydrodissection is complete to rotate the edge of the lens forwards in their technique of vertical phacoemulsification. For safety purposes, viscodissection should only be done after hydrodissection with BSS is complete and it is certain that the lens is freely mobile. Caution would dictate that viscodissection, unless used for a specific purpose, may best be left in abeyance. HYDRODELINEATION OR HYDRODELAMINATION Hydrodelineation is the term coined by Anis Aziz to describe the cleavage of lens structures through the injection of fluid. It is also termed hydrodelamination or hydrodemarcation. The technique is fairly simple. A small bore cannula (26–28 G), blunt-tipped, attached to a Luer-lok 1.00 ml plastic syringe, filled with BSS or Ringer lactate, is placed in the middle of the nucleus, and pushed forward into the nucleus till it reaches the middle of the nucleus (in soft cataracts), or meets resistance (medium to hard cataracts). The point of resistance is where the soft outer nucleus meets the harder central nucleus. At the point of resistance, the cannula is pulled back a fraction of a millimeter, and the fluid is injected. The fluid passes into the body of the cataract, and the dissected plane is usually identified by the appearance of a golden ring around the nucleus. This golden ring may not always be visible nor always clear depending on the density of the cataract. Sometimes only a dark separation plane may be noticed. As with hydrodissection, hydrodelamination must produce a cleavage and

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Figs 12.5 and 6: Hydrodelineation showing golden rings

a good separation of the nucleus from the epinuclear zone. If only a portion of the ring appears (Fig. 12.5 and 12.6), it may be necessary to reintroduce the cannula in a different place and try to inject the fluid again. It is important to appreciate the differences between hydrodissection and hydrodelamination. Hydrodissection is done to permit phacoemulsification in the bag. If the nucleus did not rotate, it would not be possible to chop a lens, rotate the nucleus for further chopping, and it would also not be possible to allow each sequential piece of the nucleus to be rotated into its best place for removal. None of these techniques could be possible if the nucleus remained adherent to the capsule. On the other hand, hydrodelamination is performed for safety. Hydrodelamination was a necessary preliminary step in the phacoemulsification technique of four-quarter grooving. It tells the surgeon how far he could groove with ultrasound into the periphery without taking any risks. In addition, hydrodelamination involves separation of the peripheral softer epinucleus from the deeper harder nucleus. Thus, in essence, the harder nucleus sits on a softer epinucleus bed. One can phaco the harder part with impunity knowing that the peripheral softer nucleus acts as a buffer safe zone. To recapitulate, the firm nucleus can be worked on within the softer nucleus of almost rubber-like consistency. This particular technique is especially useful with endocapsular phacoemulsification with nuclear cleavage and with the chip and flip technique. Decompression of the Capsule Bag Decompression of the capsule bag means reducing the pressure by allowing the excess fluid to leak out of the sides of the capsular bag and out of the anterior chamber. If the nucleus is hard, hydrodelamination becomes an impossibility, and there even hydrodissection becomes technically difficult. In a dense nucleus the fluid wave is no longer visible and the fluid injection seems to have no effect. The surgeon is tempted to inject more and more at a higher pressure hoping to get a separation, but what does happen however is that the posterior capsule tents backward and as the pressures increases, the thin capsule gives way, rupturing. It is thus a disaster waiting to happen.

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How does one recognize that this complication is impending? In a soft cataract even a single injection at a single site under the capsule while doing hydrodissection is adequate. However in the case of a hard or a suprahard cataract, it is important to inject at multiple points. This disperses the fluid and gives more sites for the fluid under pressure, to escape. The second important step is to compress on the nucleus, with the heel of the cannula after every injection, which disperses the fluid. In case the fluid does not come out, two important signs have to be recognized: the chamber shallows very much, and the eye pressure rises sharply. The tendency of the surgeon is to reform the chamber by either injecting a viscoelastic, or still worse, by pressing on the nucleus with a repositor or cannula. Both techniques will lead to a posterior rupture. The correct way of handling this situation is to insert a thin blade iris repository under the edge of the capsule, at 5 O’clock and simply sweep it in both directions. Almost immediately the surgeon will be rewarded with a gush of fluid (which had been entrapped) and the eye immediately softens. Hydrofracture It is a technique, which involves possible separation of the lamella of the internal nucleus by a combination of ultrasonic needle penetration and a pressure injection of BSS. This method is known as a hydrosonic technique and was commenced by Dr Anis of USA. It has the advantage that it fragments the nucleus into little fine bits permitting easier phacoemulsification. However, with the advent of chopping technique it is now rarely utilized and is purely of academic interest. CONCLUSION Both the techniques of hydrodissection and hydrodelamination have the advantage that they also help the surgeon assess the degree of hardness of the lens and therefore, indirectly assess the quantum of ultrasound time, which would be required. Both techniques are essential and though in standard chopping methods hydrodelamination is not utilized, it still is a useful method especially if one expects difficulties to occur during the surgery. It also has the advantage that if a rhexis has been done a little too small, hydrodemarcation reduces the nucleus into its component parts diminishing the size thus, permitting the hard nucleus to be chopped and removed within the soft epinucleus buffer zone. FURTHER READING 1. Fine IH: Cortical cleaving hydrodissection. J Cataract Refract Surg 18(5:) 508-12, 1992. 2. Mehta KR, SM Sathe, SD Karyekar: Computer Terminal Usage and Eye Fatigue, Xth Congress APAO. Soc Proc 2:946-48,1985. 3. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-6,1986. 4. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989. 5. Mehta KR: Clear corneal phaco with injectable silicone IOL proc. All India Ophthl Soc Proc (Mumbai) 1995.

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6. Mehta KR: Mehta tangential chop (MTC) technique for phacoemulsification. All India Ophthl Soc Proc (Chandigarh) 1996. 7. Mehta KR: Combined astigmatic annular keratotomy and phaco—a corneal topographic analytical technique. All India Ophthl Soc Proc (Chandigarh) 1996. 8. Mehta KR: Phaco-levitation—a peaceful way. All India Ophthl Soc Proc (Chandigarh) 1996. 9. Mehta KR: Lollipop phaco cleavage—a new technique for hard cataracts. All India Ophthl Soc Proc (Bangalore) 1991. 10. Mehta KR: SICS mon-phaco—hydroexpression with an irrigating vectis. Proc of SAARC Conference, Nepal, 1994. 11. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 12. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

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Noshir M Shroff Ranjan Dutta Gurpreet Singh

Phacoemulsification: The Quadrantic Cracking, Chopping and Stuffing Technique

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INTRODUCTION Phacoemulsification if it proceeds smoothly is an excellent procedure with early and extremely gratifying visual recovery. However, should a complication arise, the result can be disastrous with the patient’s sight under threat. A surgeon’s skills may range from excellent to average. An excellent surgeon will not have much difficulty in adapting to any new procedure including phacoemulsification. Unfortunately not many surgeons belong to this category, where there is little or no difficulty in adapting to the new technique of phacoemulsification. The vast majority of us belong to the second group of “average surgeons”. Not uncommonly an average surgeon begins phacoemulsification, has a few complications in the first few cases, loses confidence and gives up. Therefore, a nucleofractis technique which is useful for the vast majority of average surgeons, would be one which has a high order of safety with least chances of a posterior capsular rent and damage to the corneal endothelium, is easily reproducible and is easy to perform. Modern nucleofractis techniques can broadly be divided into two types: (i) four quadrant cracking, and (ii) stop and chop technique. Four-Quadrant Cracking (Shepherd’s Modification of Gimbel’s Divide and Conquer Technique) It is easier to handle four small quadrants rather than two large halves. Hence, this technique is easier for the beginner. Moreover, central sculpting debulks the hard central nuclear core. However, the disadvantage is that this technique uses more phaco power and phaco time.

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Stop and Chop (Koch’s Modification of Nagahara’s Phaco Chop Technique) This technique has the advantage of using less phaco power and time as compared to quadrantic cracking. It is a very effective technique for hard nuclei. However it is an inherently difficult procedure for the beginner. A nuclear half is simply too big a piece to tackle and most complications of this technique arise due to this fact. The large nuclear cumbersome fragment, if not impaled exactly midway, tends to rock sideways on the phaco tip, particularly if the occlusion is not adequate. The lack of firm grip on the piece makes subsequent chopping frustratingly ineffective. Moreover, the absence of a second trench in the Stop and Chop technique makes it difficult to convert each “half” into “quarters”. As the chopper moves toward the center from the periphery, the final portion (i.e. the central bulk of the nucleus) is difficult to chop. Interconnecting fibrils may at times pose difficulty in separating the fragments, necessitating the use of excessive force with the chopper (Fig. 13.1). Significant lateral forces are thus required for separating the fragments. This puts stress on the capsular bag and makes it an unsafe procedure. In contrast to this, the pre-existent second trench perpendicular to the first, in the quadrantic-cracking technique, makes fragment separation possible with minimal lateral force.

Fig. 13.1: In the Stop and Chop technique (above), the final portion i.e. the central bulk of the nucleus is difficult to chop. Interconnecting fibrils make separation of the fragments difficult. Significant lateral forces are thus created which put stress on the capsular bag. On the other hand in the Quadrantic cracking technique (below), pregrooving leaves a thin posterior nuclear plate and minimum force is required to crack each nuclear half into quarters

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The danger of damage to the lens capsule in the Stop and Chop technique is very real. A forceful phaco chop can easily cause a posterior capsule rent. A large fragment will require a longer centripetal chop, which may inadvertently tear the edge of the rhexis and extend it. One may avoid the rhexis edge with a shorter centripetal chop (i.e. by starting at the midperiphery rather than the equator), but this will eventually require wider lateral separation of the nuclear fragments and put stress on the capsular bag. Also, multiple phaco chops give rise to multiple fragments. These can act as splinters, and in conjunction with anterior chamber turbulence, cause endothelial damage. Keeping in mind that most of the above complications occur only due to the large nuclear “halves”, we have devised a technique that combines the best features of both techniques. QUADRANTIC CRACKING, CHOPPING AND STUFFING TECHNIQUE Our technique of quadrantic cracking, chopping and stuffing starts with four-quadrant fracture followed by tackling each quadrant using low power and high vacuum settings. Thus it combines the safety of quadrantic cracking with the efficacy of Stop and Chop and is suitable for most grades of nuclei. Preliminary Steps Following suitable ocular anesthesia, a small conjunctival flap is made and a bloodfree zone is created with a bipolar cautery. The authors prefer prefer making a posterior limbal incision to a clear corneal incision, as it results in lesser induced astigmatism and provides a longer tunnel, which is self-sealing and watertight (due to its valve-like action). A limbal incision also has the advantage that it can be covered with the conjunctival flap at the conclusion of surgery, which acts as an additional barrier against intraocular microbial invasion. The anterior chamber is filled with a high molecular weight cohesive viscoelastic substance and a side port incision is prepared. Capsulorrhexis is performed using a bent 26-gauge needle followed by hydrodissection (and sometimes hydrodelineation). These two steps are absolutely necessary and provide the key to successful phacoemulsification. Bimanual rotation using two lens hooks ensures that the nucleus has adequately been separated from the cortex. Central Debulking and Pregrooving The first step is to create a groove from the center of the nucleus towards 6 O’ clock, stopping just short of the edge of the rhexis. The parameters the authors use during sculpting are 50% U/S power (linear mode) and 30 mm Hg vacuum (Fig. 13.2). The bulk of phaco power is used in this step. The phaco tip is deep inside the central core of the nucleus. So, most of the phaco energy is dissipated within the nucleus far away from the endothelium and the posterior capsule. The groove is created by shaving in layers and is as wide as the sleeve of the phaco

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Fig. 13.2: Sculpting is done by shaving layers towards 6 O’clock. Ultrasonic power is at 50% (linear mode) with vacuum at 30 mm Hg. The starting point of the first groove is slightly nearer the superior pole and not at the exact center

tip and as deep as possible. Using a spatula (second instrument) through the side port incision the nucleus is rotated by 90° and a second groove is created in a similar manner (Figs 13.3 and 13.4). This is followed by the third and the fourth grooves. One should ensure during sculpting that the starting point of each groove is slightly nearer the superior pole of the nucleus and not at the center itself (Fig. 13.5). Otherwise at the end of sculpting a thick central mound may be left on the center of the posterior nuclear plate and will make subsequent cracking difficult. In this regard a Kelman tip is very useful. Its tip has a bend close to its distal end and permits very effective and efficient downslope sculpting in the superior part of the nucleus, allowing prompt access to the posterior plate for fracturing. Thus there is no residual central mound and one is left with a thin and evenly shaved posterior plate. Additionally this shape allows working on either the left or right side of the central trench by simply turning the tip in either direction along its long axis. The authors have found this tip extremely useful in moderate to hard nuclei. Another point that needs to be kept in mind while sculpting is that one should ensure adequate depth of the grooves so as to easily facilitate cracking. An indicator of adequate sculpting is the presence of red glow seen through the thin posterior nuclear plate (Fig. 13.6). Finally, once the center has been debulked and all four grooves have been made, one is left with the nucleus resembling a Maltese cross.

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Fig. 13.3: The second instrument is used to rotate the nucleus by 90 degrees in preparation for the second groove

Fig. 13.4: The second groove is made perpendicular to the first

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Fig. 13.5: If sculpting is started at the exact center, it is difficult to gain access to the deeper portions of the nucleus leaving behind a central mound especially if a straight tip is used. The Kelman tip permits effective and efficient downslope leaving a thin and evenly shaved posterior nuclear plate

Fig. 13.6: After all four grooves have been created, they are further deepened till a satisfactory red glow is obtained

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Fig. 13.7: Cracking is achieved with minimal horizontal force

Cracking Since the central hard core of the nucleus has already been debulked and all four grooves have been created with adequate depth, cracking is easily performed using the phaco tip and the second instrument with minimal horizontal force (Fig. 13.7). Thus undue stress on the capsular bag has been avoided. For this step the foot pedal is kept in position 1. The fracture is attained by the two instruments pushing away from each other (phaco tip to 9 O’clock and second instrument to 3 O’clock). Alternatively, beginners may find cracking easier by simply using two hooks. The first fracture divides the nucleus into two halves. Following this, the nucleus is rotated by 90° and the distal “half” is fractured into “quarters” using the pre-existent groove. The other nuclear half is rotated distally and similarly cracked till we achieve four separate quadrants (Fig. 13.8). Sometimes the first fracture does not completely divide the nucleus into two halves. In this case, the fracture is completed by rotating the nucleus by 180° and performing cracking on the undivided portion. Segment Removal The parameters are now changed. Ultrasonic power is reduced to 30% (pulse mode) and vacuum is increased to 120 mm Hg and the authors now proceed as one would in the Stop and Chop technique, i.e. engaging and holding each nuclear fragment and chopping it into smaller pieces.

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Fig. 13.8: The nucleus is rotated every 90 degree till four separate nuclear quadrants are obtained

One can engage each quadrant from the apex, the sides or the undersurface. However, the apex offers too small an area to ensure a good hold and the sides of the fragment have very irregular surfaces. Engaging a quadrant from an irregular surface can cause it to tumble and rent the posterior capsule (Fig. 13.9). Therefore, the authors prefer to engage the quadrant from its undersurface; its area is large and smooth and the phaco tip can be effectively occluded thus providing a good hold on the fragment. There are two ways of achieving this. One way is to depress the base of the fragment with a hook thus tilting up the apex and exposing the undersurface of the quadrant to the phaco tip (Fig. 13.10). The other way is to lift up the apex directly with the hook and guide the phaco tip to the undersurface (Fig. 13.11). Once the quadrant has been effectively impaled onto the phaco tip, it is pulled to the center of the capsular bag away from the posterior capsule, and the endothelium and a chopper is introduced through the side port. With the phaco tip holding the quadrant steady, the chopper is sunk into the nuclear substance and retracted towards the phaco tip (Fig. 13.12). Just before it reaches the tip, the chopper is moved sideways and away from the tip (towards 3 O’clock). Simultaneously the

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Fig. 13.9: Engaging a quadrant from an irregular surface can cause it to tumble and cause a rent in the posterior capsule. Engaging by the undersurface prevents this besides providing a good hold on the piece

Fig. 13.10: The second instrument presses down on the base of the quadrant thus raising the apex. The undersurface is now exposed to the phaco tip which can effectively engage it

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Fig. 13.11: Alternatively, one can directly lift the apex with the second instrument and guide the phaco tip below the quadrant. One should ensure that the bent part of the Sinskey hook is kept horizontal and not pointing down towards the posterior capsule. This step should be attempted in pedal position 1 (irrigation) which will ensure that the hook as well as the phaco tip is well away from the capsule

Fig. 13.12: With the phaco tip effectively holding the quadrant, the chopper is sunk into the nuclear substance and retracted towards the phaco tip

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Fig. 13.13: As the chopper approaches the phaco probe it is moved sideways and away from the tip. Simultaneously the tip holding the nucleus is moved in the opposite direction

phaco tip is moved sideways in the opposite direction (towards 9 O’clock) dividing the quadrant into two fragments (Fig. 13.13). The chopper guides the engaged piece and then stuffs it into the phaco tip, all the time keeping the other fragments away (Fig. 13.14). The fragment is emulsified using a combination of this stuffing action, high vacuum and intermittent bursts of low phaco power. Likewise each quadrant is tackled in this manner by this method of chopping, stuffing and emulsification. One must all the time ensure that epinuclear and cortical matter is not aspirated during segment removal as this material acts as a protective buffer and prevents accidental posterior capsule rupture. Epinucleus Removal With ultrasonic power set at 10% (linear mode) and vacuum at 80 mm Hg the distal rim of the epinuclear shell is engaged by the phaco probe in pedal position 2 and pulled towards the center of the capsular bag. The epinucleus is pulled by the phaco tip towards the incision, while the second instrument simultaneously provides countertraction in the 6 O’clock direction. The epinucleus easily flips around the second instrument and is emulsified in the center of the capsular bag. Sometimes,

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Fig. 13.14: The smaller pieces are now stuffed into the phaco tip with the chopper and emulsified using bursts of low phaco power and high vacuum

the portion of the epinucleus engaged to the phaco tip breaks off from the rest of the epinuclear shell. In this case, after emulsifying the broken-off piece, the remainder of the shell is rotated to the 6 O’clock position, engaged by the phaco tip, brought to the center of the bag, and then finally emulsified. One should proceed very carefully in this delicate phase as the absence of the main bulk of the nucleus makes the posterior capsule relaxed and there is a danger of the floppy capsule coming into contact with the phaco tip. Thereafter cortex is removed with the irrigation-aspiration tip. The authors prefer to remove 12 O’clock cortex by the bimanual method after creating a second side port incision. The anterior chamber is then filled with viscoelastic substance and a foldable IOL is implanted. Viscoelastic removal followed by testing the wound for its self-sealing nature concludes the operation. CONCLUSION The authors have been using this technique on most of their patients with gratifying results. It combines the safety of quadrantic cracking with the efficacy of Stop and Chop and is appropriate for most types of cataracts. This technique is reproducible and is ideal for the beginner as well as the experienced.

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Richard Packard

Current Phacoemulsification Techniques

14

INTRODUCTION Small incision cataract surgery was 30 years old in 1997. Since its inception the techniques involved have been constantly improving and this has been matched by innovations in phaco machinery and intraocular lens materials and design. At almost every meeting or edition of the throw-away papers somebody puts forward some new variation. It can be very confusing. The following shows my current techniques developed over 20 years experience in small incision cataract surgery. PATIENT

PREPARATION

AND

ANESTHESIA

Preparation Patients are not routinely given any premedication. They will have had a simple drop regime prior to reaching the operating theater as follows: G. Phenylephrine 2.5% G. Homatropine 2% Two drops of each 30 minutes preoperation G. Benoxinate 0.4% Two drops every 10 minutes for 30 minutes preoperation In the operating theater prior to administering any anesthetic, povidones iodine is instilled into the eye. This will then be in contact with the tissues for about 10 minutes before being washed out at the start of the operation.

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Topical Anesthesia The drop regime above is sufficient for topical anesthesia. This technique was not used often in our department until recently because the anesthetists prefer not to give any intravenous sedation, if required, without control of the airway. The advent of intraocular unpreserved lignocaine 1% at the start of the procedure and for hydrodissection has increased the number of patients operated upon without peribulbar injection. This is because the need for additional intravenous sedation is almost eliminated. Peribulbar Anesthesia Medication Mixture Plain lignocaine 2% 8 ml mixed with hyalase. Needle

Long shank 23 gauge needle attached to 10 ml syringe.

Technique 3 ml are injected inferiorly back from the infraorbital notch and 3 ml superiorly over the supraorbital notch. Both injections point nasally. A mercury bag is then placed on the eye for about 5 minutes not to soften the eye but to help spread the local anesthetic. PHACOMACHINES

IN

USE

1. Alcon Legacy 2. Allergan AMO Prestige 3. Allergan AMO Sovereign The Legacy has the high vacuum cassettes in use and has been modified for bimodal and burst phaco. The microtip and ABS technology have improved the anterior chamber stability considerably compared with earlier configurations of this machine. The Prestige has a unique pump monitoring arrangement. This helps to minimize postocclusion break surge in the anterior chamber by slowing the rate at which the pump regains full speed. This makes it very safe as the chamber does not collapse and intracameral contents are not sucked into the phaco tip. This machine is now available with a 21 gauge phaco needle. The Sovereign is new and not yet available commercially though it is being launched shortly. It has developed on the microchip control of machine parameters seen in the Prestige and Diplomax machines. It has the ability to set different values for phaco with and without bursts of variable length, vacuum and pump speed which differs depending on whether the phaco tip is occluded or unoccluded. It is also possible to vary the pump speed in any setting depending on vacuum thresholds.

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All these machines allow a slow rise time to maximum vacuum settings which is safer when teaching residents in training. The Sovereign will allow very rapid vacuum rise time on occlusion if so desired. Tips and Sleeves Current tips are 30 degree. This provides the best compromise for sculpting and nuclear fragment removal. These are used with both machines and are covered by silicone sleeves. The Legacy has the Kelman tip also which has very much greater cavitation than conventional straight tips and is particularly useful for very hard nuclei. INCISIONS Side Port Incisions Instruments

Alcon 15 degree knife, toothed St. Martins forceps.

Technique The limbal conjunctiva is grasped with the forceps at about 11 O‘clock to steady the eye. The 15 degree knife is held in the right hand with blade parallel to the iris. The point of the knife is applied to the limbus at the capillary arcade approximately 60 degrees to the right of the tunnel incision (Fig. 14.1). The knife is advanced fully to produce an incision 1 ½ mm wide. This just the right size for the bimanual handpieces used for irrigation and aspiration. The second incision is made with the knife in the left hand at about 60 degrees to the left of the phaco incision (Fig. 14.2). They will easily self seal at the end of the procedure.

Figs 14.1 and 14.2: Side port

Note The incision is made at the edge of the capillary arcade so that the small amount of bleeding will mark its site for insertion of the nucleus manipulator later. Temporal Incision Instruments Colibri toothed microsurgical forceps, Alcon phaco slit blade 2.75 mm angled.

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Technique The Colibri forceps grasp the limbus at the left end of the incision site to steady the eye. A Fine Thornton ring will also do this very well. The tip of the slit knife is held against the limbus at an angle of 60 degrees. The knife is pushed gently (Fig. 14.3) forward until the bevel is just covered. The knife is then angulated backwards so that the blade is pointing up the slope towards the center of the cornea. The blade is now advanced (Fig. 14.4) very slowly. The progress Fig. 14.3: Starting the phaco incision of the passage of the knife can be seen clearly. When the tip of the knife is 2 mm into clear cornea the handle is lifted and the knife advanced again (Fig. 14.5) but this time pointing to the scleral spur opposite. When this last is done slowly a straight entry into the anterior chamber is produced which acts efficiently as an internal valve. ANTERIOR

CHAMBER

MAINTENANCE

The chamber is now filled with viscoelastic through the side port. Provisc (sodium hyaluronate 1%) is what I use at present. I do not think there is much too choose between the various sodium hyaluronates, however HPMC does not perform as well in the eye but it is cheaper. Viscoat is reserved for problems during the phaco to tamponade a posterior capsule rupture. Capsulorrhexis Instruments Straight disposable cystitome, Duckworth and Kent titanium capsulorrhexis forceps. Technique • The eye is overfilled with viscoelastic elastic as above to flatten the anterior capsule.

Fig. 14.4: Advancing the slit knife

Fig. 14.5: Making the internal incision

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Fig. 14.6: Cystitome cutting capsule

Fig. 14.8: Folding the flap onto the untorn capsule

Fig. 14.7: Starting to tear with forceps

Fig. 14.9: Finishing the rhexis

• Refocus the microscope on the anterior capsule and make sure there is good magnification, particularly if there is a less than helpful red reflex. Note There is much less tendency for the capsular tear to move peripherally during the rhexis if the surface is flattened out. If the surgeon is worried about the rhexis getting out of control at any stage of the capsulotomy , more viscoelastic injected into the eye will usually arrest the problem. • The cystitome is attached to the irrigation handpiece or the viscoelastic syringe and inserted through the tunnel. The instrument held in the right hand is steadied by the index finger of the left hand. The capsule in the center of the lens is engaged with the tip of the cystitome and the sharp edge is used to cut the capsule for about 1 mm (Fig. 14.6). The capsule is then torn in a C-shape. The flap of capsule thus created is laid on top of the adjacent untorn capsule so that it can easily be grasped by the capsulorrhexis forceps. • The capsulorrhexis forceps having been inserted into the eye are used to grasp the capsular edge. This is then torn in a circular manner constantly changing the angle of the vector forces by regripping the capsular edge as the tear progresses (Figs 14.7 to 14.9).

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Note The ideal angle of pull to produce the tear depends on both a horizontal and a vertical component. This is particularly important in young eyes with elastic capsules. Do not expect the capsule to tear in the direction you are pulling Capsules vary considerably in consistency and elasticity. As a general rule the younger the patient the more elastic and these capsules are much more difficult to control. The angle of pull is often at an obtuse angle to the direction of tear to prevent drift to the periphery. Aim to make these capsulotomies small (4mm) and they will probably end up about 6 mm. Capsulorrhexis

Size

The ideal size for a capsulorrhexis is between 5 and 6 mm. In any event the capsulorrhexis should lie on the edge of the implant. Making it any larger can lead to difficulties with control and is unnecessary. With some implant materials (such as silicone) it is particularly important that at the end of the procedure the rhexis is not too small. A rrhexis of 4.5 mm or less may lead to contraction and capsulophimosis. The implant may then decenter and the patient experience glare from the opaque edge of the capsule. Note

If the rhexis looks too small after the I/A enlarge it.

Technique Inject viscoelastic into the anterior chamber; do not overfill it as this will put the capsule under tension. Use Vannas scissors to make an oblique cut at the rhexis edge, grasp this new tear with the capsulorrhexis forceps and tear carefully round. Reasons for Problems with Capsulorrhexis • The most common problem is loss of control of the tear so that it moves peripherally (Fig. 14.10). This may be due: i. Elasticity of the capsule combined with lack of rigidity of the sclera as in younger patients (Figs 14.11 and 14.12). ii. Excessive pressure from behind the lens. iii. Any other cause for loss of the anterior chamber and escape of viscoelastic.

Fig. 14.10: Rhexis moving peripherally

Fig. 14.11: Elastic juvenile capsule

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Fig. 14.12: Preventing capsule going to periphery by pulling away from tear

Fig. 14.13: Leakage of liquid lens material as the capsule is punctured

The cure for all of these is to inject more viscoelastic, if the problem persists change to a high viscosity viscoelastic such as Healon GV. • If the tear appears to stop this is due to anterior zonular fibers abnormally far forward. Do not persist with the rhexis in this direction or it will rapidly tear towards the equator. Start the rhexis the other way round by making a small cut with Vannas scissors and then joining it up again at the point where it had previously stopped. • When there is a poor or no red reflex as in white cataracts or very advanced nuclear cataracts with extreme sclerosis capsulorrhexis can be very taxing. There are a few simple maneuvers which will improve visibility somewhat: i. If you do not do so already, sit temporally, visibility is enhanced. ii. Tilt the microscope so that the light is oblique to the capsule and will reflect from the torn edge. Or use the oblique (non-coaxial light) if available on the microscope. iii. Increase the magnification so that the iris fills your field, focus accurately. What you lose in depth of field is gained by ease of vision of the capsular edge. iv. In white cataracts (Figs 14.13 and 14.14) when liquid lens material fills the eye as the capsule is punctured, use the I/A to clear the chamber and suck out anterior cortex. Refill the eye with viscoelastic, your view of the capsule will then be much better. • Small pupils, although they can be enlarged by various means, still make the rhexis more difficult. Viscoelastic may be used to push the pupil open and thus expose more capsule. Also the nucleus manipulator can push the iris aside (Fig. 14.15), in the area where the capsulorrhexis forceps are tearing the capsule HYDRODISSECTION Instruments Visitec hydrodissection cannula (with rectangular cross-section), 2 ml disposable syringe filled with BSS.

CURRENT PHACOEMULSIFICATION TECHNIQUES

Fig. 14.14: Using the I/A for removing excess soft lens matter

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Fig. 14.15: Using the nucleus manipulator to hold aside the iris

Technique As the hydrodissection cannula is moved towards the rhexis start to inject BSS to lift its edge. The hydrodissection cannula is placed under the edge of the capsule at about the 3 O‘clock position. The capsule is tented up to peel it off the cortex and advanced 1 mm peripherally. BSS is injected rapidly but smoothly to produce cortical cleavage. This is seen as a fluid wave (Fig. 14.16) advancing rapidly under the nucleus and epinucleus. The tip of the cannula is then placed on the center of the nucleus and then pushed backwards towards the posterior capsule (Fig. 14.17). This maneuver has the effect of helping to spread the fluid around the capsule and complete the cleavage. If it is felt that the hydrodissection is incomplete, a second injection of BSS can be made at the 6 or 12 O‘clock position. In hard or medium cataracts it may be difficult to separate nucleus from epinucleus as in hydrodelineation and is often not necessary. If it is felt desirable to get the hard part of a nuclear fragment away from its attached epinucleus during phaco this can be done with the nucleus manipulator. However in soft cataracts, it is advantageous to see clearly the extent of the nucleus, so that the phaco tip does not inadvertently pass through soft nucleus, epinucleus and capsule.

Fig. 14.16: Fluid wave traveling behind nucleus

Fig. 14.17: Pressing back on the nucleus to spread the fluid

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Sometimes with very soft cataracts, part of the nucleus is pushed through the rhexis during the hydrodissection, this does not matter. It will facilitate the aspiration of the soft nucleus. LENS

REMOVAL

General Points • Check that the machine is working satisfactorily before placing the phaco tip in the eye. This includes making sure the machine parameters are those desired. • Check that the phaco tip is undamaged and that its bevel is at 90 degrees to the irrigation sleeve openings. The exposed tip should be about 1.5 mm beyond the end of the sleeve. • Check that the foot pedal is comfortably placed. Instruments Colibri toothed microsurgical forceps, phaco handpiece, Duckworth and Kent nucleus manipulator (actually called a Mackool iris repositor). Technique for Soft Nuclei Machine Settings

Alcon Legacy

AMO Prestige

AMO Sovereign

Phaco tip bevel Bottle height Sculpting Vacuum Aspiration rate Nuclear removal Vacuum Phaco power

30° 21 gauge 70 cm

30° 19 gauge 70 cm

30° 19 gauge 70cm

40 mmHg 15 cc/min

35 mmHg 18 cc/min

10 mmHg 20 cc/min

200 mmHg 30% linear

150 mmHg 30% linear

200 mmHg 20% linear

Emulsification The Colibri forceps are used to lift gently the edge of the wound and the phaco tip enters the eye bevel down. The machine should be in foot position 0 as the anterior chamber is still deepened by the viscoelastic. Note If the eye has a shallow chamber, or the pupil is not well dilated and the iris is at risk of damage as the phaco tip enters the eye, redeepen the chamber with viscoelastic. If Viscoat is available and it is being used to protect the endothelium during phaco anyway then this problem will not arise. Once the irrigation ports are safely in the eye, the foot pedal is depressed to position 1 allowing the irrigation fluid to deepen the anterior chamber. • Sculpting: With soft cataracts it is very easy to pass straight through the lens if too much power is used when sculpting. It should be done with smooth movements and the edge of the delineated nucleus should not be passed. Make a deep central groove because even though it may not crack, it will facilitate the pulling of the edge of the lens centrally after it has been sliced.

CURRENT PHACOEMULSIFICATION TECHNIQUES

Fig. 14.18: Slicing the nucleus

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Fig. 14.19: Separating the sliced nucleus

• Nucleus removal: i. With the phaco tip in the eye in irrigation mode insert the nucleus manipulator through the side port incision. ii. Pass the tip of the manipulator (turned on its side) under the rhexis and out to the equator of the nucleus in the 3 O‘clock position. iii. Engage the nucleus with the manipulator and pull towards the central groove (Figs. 14.18 and 14.19), as the manipulator reaches the groove, use the phaco tip to separate the Fig. 14.20: two sides of the cut you have made. It does not matter if there is full separation or not. iv. Turn the nucleus with the manipulator and the phaco tip and repeat the chopping at intervals of two clock hours. This technique known as the “soft slice” will mean that the segments of nucleus even though they are not separated will fold in towards the center of the eye when they are engaged by the phaco tip. v. Bury the phaco tip in one of the segments. No U/S power is needed for this because of the softness of the nucleus. Allow vacuum to build and when it has, pull the segment (Fig. 14.20) centrally for removal. The nucleus will peel apart along the preprepared cuts. Do this for each part of the nucleus. vi. The epinuclear shell will still be in the eye, but because of the cortical cleavage hydrodissection, will be free to be aspirated. Pass the phaco tip under the rhexis edge into the epinucleus at 6 O‘clock and as vacuum builds pull it centrally for removal. Do not use U/S as this will break occlusion and also punch holes in the epinucleus. Sometimes the manipulator is needed to help the phaco tip to engage the epinucleus by moving it from the equator towards the center.

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Technique for Medium Hard Nuclei Machine Settings

Alcon Legacy

AMO Prestige

AMO Sovereign

Phaco tip bevel Bottle height Sculpting Vacuum Aspiration rate Nuclear removal Vacuum Aspiration rate Phaco power

30° 21 gauge ABS 70 cm

30° 19 gauge 70 cm

30° 19 gauge 70cm

40 mmHg 15 cc/min

35 mmHg 18 cc/min

10 mmHg 14 cc/min

350 mmHg 25 cc/min 70% linear

260 mmHg 16 cc/min 60% linear

400 mmHg 18 cc/min 50% linear

This type of cataract is by far the easiest to remove. The nucleus offers some but not too much resistance to emulsification but also has enough substance to allow easy hydrodissection, manipulation and cracking. It is the ideal type of nucleus for beginners to learn on. Emulsification The eye is entered as already mentioned for the soft cataract. • Sculpting: In medium hard cataracts the nucleus offers some resistance to sculpting. Accordingly, the amount of power needed to emulsify it is that which does not push the nucleus across the eye. It is better to press down with the foot and increase the phaco power than put the superior zonules at risk by pushing at the nucleus. The anatomy of the nucleus should be borne in mind during sculpting. Initially the anterior cortex is removed widely to expose the hard core. This core is then grooved to a depth of 90% of the nuclear thickness. Note As nucleus hardness increases the passes of sculpting should attempt to remove thinner and thinner slivers of nucleus. Note As the phaco tip advances it should be slightly elevated to avoid passing straight through the nucleus. It is important to remember that the center of the nucleus is 2.5-3.0 mm but that because of its elliptical cross-section this reduces rapidly as the phaco tip moves peripherally. The grooves in the nucleus need not go beyond the edge of the 5.0 mm rhexis, provided that sufficient depth has been achieved cracking will occur easily with grooves of this length. It is also important that they are not significantly wider than the phaco needle or else cracking will be much less efficient. Tips for Judging the Depth in the Nucleus when Sculpting • Remember the diameter of the phaco needle (0.9-1.1 mm) • Remember the anatomy of the lens with hard central nucleus surrounded by epinucleus and cortex that are softer • Watch the change in the red reflex, it gets brighter • Refocus the microscope frequently so that the focus is at the plane of emulsification

CURRENT PHACOEMULSIFICATION TECHNIQUES

Fig. 14.21: Cruciate grooves

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Fig. 14.22: Cracking I

When the first groove has been made, the nuclear manipulator is passed into the eye through the side port and placed in the groove. The nucleus is then rotated anticlockwise to present the next area of nucleus to be sculpted. These medium hard nuclei are generally easy to rotate. Following the fashioning of all four grooves (Fig. 14.21) to create a cruciate shape of appropriate depth, the nucleus can be cracked. Note Although I have used the chopping technique and still do to facilitate the removal of large nuclear fragments. I find that my technique for nucleofractis is the most predictable and consistent, also it is the easiest to teach our residents in training. • Cracking i. Using the manipulator to move the nucleus so that a groove is placed at the apex of the triangle formed by the phaco tip and the manipulator. ii. These two instruments (Figs 14.22 and 14.23) are then put at the bottom of the groove. iii. The phaco tip stabilizes the nucleus while the manipulator moves to the left. In a medium hard nucleus little effort should be needed to crack it. The crack should take place centrally but the effect should cause the equator to separate also. This is important for quadrant removal later. • Quadrant removal i. Each quadrant is split in turn and then the manipulator is used to lift the apex of the first quadrant to present it to the phaco tip (Fig. 14.24). Note If the first quadrant that is approached for removal does not readily detach itself from its position, move to the smallest and try to engage it. Once one quadrant has been removed the others come easily. ii. Initially the foot pedal is used in position 3 (phaco mode) to impale the nuclear quadrant on the phaco tip and thus cause occlusion. The foot pedal is now moved into position 2 (I/A) and vacuum is allowed to build. When it is felt that a good grip has been achieved on the nuclear quadrant it can be moved to the center of the capsulorrhexis. In this position using mostly vacuum assisted by low levels of linearly controlled U/S power, the quadrant is emulsified.

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Fig. 14.23: Cracking II

Fig. 14.24: Lifting the first quadrant

iii. The next quadrant is moved into position by the manipulator, tilted up and emulsified as already described. The remaining two quadrants are dealt with similarly. Note With the higher levels of vacuum currently being used, care must be exercised to avoid anterior chamber collapse when occlusion breaks. A number of methods are available on modern machines to mitigate against this eventuality. Firstly continuous irrigation, here even in position 0 the chamber will always be filled so that the postocclusion break surge is neutralized. The use of non-compliant tubing as used in all the machines the author currently uses will help to minimize the effect of any residual line vacuum. On the AMO Prestige phaco machine a mechanical model of events in the anterior chamber exists in relation to the pump mechanism. This allows the pump speed to slow to 0 after occlusion and maximum vacuum has been achieved. As the piece of nucleus being removed clears the tip and occlusion breaks, instead of the pump accelerating to its predetermined speed it reaches it after a pause. The anterior chamber can thus equilibrate without any risk of collapse. This is particularly important with harder cataracts. The Aspiration Bypass System tips on the Legacy approach chamber fluidics in a different way. Here there is a small hole drilled in the phaco tip near to its base. This means that there is a constant flow of fluid through the needle even when in full occlusion. Thus occlusion break response is thus considerably lessened and much higher vacuum levels can then be used efficiently and safely. The Sovereign has even more monitoring of the anterior chamber than the Prestige, with the sampling of the pressures in the anterior chamber many times per second. The machine can be programmed to respond to a whole range of predetermined thresholds during phaco, which may vary between occluded and unoccluded modes. However where these mechanical aids are not present, surgeon anticipation of the likelihood of this event has to suffice. The foot pedal has to be lifted immediately prior to the clearing of the port in the phaco tip.

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Technique for Hard Nuclei Machine Settings

Alcon Legacy

AMO Prestige

AMO Sovereign

30° ABS Kelman 80 cm

30° 80 cm

30° 80 cm

Sculpting Vacuum Aspiration rate

40 mmHg 20 ml/min

35 mmHg 18 ml/min

10 mmHg 20 cc/min

Nuclear removal Vacuum Aspiration rate

400 mmHg 25 mmHg

260 mmHg 16 mmHg

400 mmHg 18 mmHg

100% panel if required 90% linear 60% linear

100% panel if required 90% linear 60% linear

80% panel 60% linear 60% short bursts unoccluded 60% continuous occluded

Phaco tip bevel Bottle height

Phaco power Sculpting Nuclear removal

The hard nucleus presents the phaco surgeon with one of his greatest challenges. The ability of the tip to penetrate the nucleus, often in the face of weak zonules and combined with controlling sharp nuclear fragments so as to avoid damaging capsule or endothelium need special skills to avoid problems. • Sculpting: In order to minimize the movement of the nucleus away from the phaco tip which might put the zonules on the stretch, high ultrasonic power settings are necessary. The use of maximum power on panel control means the greatest possible acceleration of the tip into the hard nucleus, thus it is more efficient and ultimately less power is used. Since adopting this approach phaco times in hard nuclei have been reduced and nuclear movement largely eliminated. The Kelman tip with its high cavitation also helps considerably. Note In hard cataracts the cut edge of the nucleus produces (Fig. 14.25) a characteristic white tramline. This will alert the surgeon when a good red reflex suggested only a moderately hard nucleus. • Cracking: In hard cataracts cracking may be relatively easy as the nuclei are some times quite brittle. However the plates of the nucleus (Fig. 14.26) often do not part cleanly, therefore it is essential to make sure that the grooves in the nucleus are of adequate depth. The most common cause of cracking difficulties with hard nuclei is due to insufficient depth of the grooves. If problems arise return to each groove and gently redeepen it. This may be facilitated by lengthening the amount of the phaco trip protruding from the sleeve (Fig. 14.27). Make sure that all quadrants are well separated before starting to remove them. • Quadrant removal: Hard nuclei are also large nuclei, it is often sensible once the quadrant has been well engaged by the phaco tip to take a chopper and reduce the size. This is done by pulling the chopper from the periphery of the quadrant towards the phaco tip. Maintaining occlusion of the tip is vital

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Fig. 14.25: White tramlines of a hard cataract

Fig. 14.26

to avoid hard fragments of the nucleus careering around the anterior chamber. It is important to balance vacuum and power and so avoid lens chatter. Once the fragment of nucleus has occluded the port on the phaco tip, even with hard cataracts, surprisingly little ultrasonic power is required to massage it through (Fig. 14.28). Lens chatter causes the nuclear fragments to bounce away from the tip, this has two effects. Firstly the hard pieces of nucleus will abrade the endothelium and second the machine is working inefficiently and far more power than necessary will be used, it will also take longer. As discussed already those phaco machines such as those used by the author which allow high vacuum and have advanced fluidics to minimize postocclusion break surge improve safety and efficiency in these difficult eyes. Note There is often little in the way of protective epinucleus in hard cataracts. Injecting Viscoat above and below the nuclear fragments not only protects the endothelium and posterior capsule it also holds the fragments stable in the anterior chamber as they are emulsified.

Fig. 14.27:

Fig. 14.28: Full occlusion for nuclear removal with high vacuum and low phaco power with the Sovereign

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Emulsification in Special Situations Small Pupil Modern nuclear disassembly techniques allow much safer phaco than previously in small pupil cases. There are two situations that are commonly found, firstly eyes with small but mobile pupils, and second pupils stuck down by synechiae. • If the pupil is not smaller then 3.5 mm and is mobile, overdeepening the anterior chamber will usually allow enough capsule to be exposed to permit capsulorrhexis. If not, judicious use of the nucleus manipulator following the forceps around the rhexis will mean it can be completed without pupil modification. The manipulator is used also to move the iris away from the phaco tip (Fig. 14.15) in the immediate area where it is working during emulsification. This will allow the grooves for nucleofractis to be cut safely. Note It is essential to ensure good hydrodissection in these cases, as visibility is so limited. • Pupils which are stuck by synechiae are often very small (1 mm). There is no way that the case can be completed without enlargement of the pupil. Enlargement of the Pupil Instruments Viscoelastic syringe with Rycroft cannula, two nuclear manipulators. Technique i. Synechiae are broken down initially with viscodissection (Fig. 14.29). The viscoelastic cannula is introduced through the side port incision and the tip placed through the pupil. Viscoelastic is injected gently to free the iris from the anterior lens capsule. This should produce a round but very small opening when the anterior chamber is further deepened with viscoelastic. ii. The two manipulators are then introduced one through the side port and one through the tunnel incision. They are used to stretch the iris gently from 3-9 O‘clock and from 6-12 O‘clock (Fig. 14.30). This will breakdown

Fig. 14.29: Breaking down synechiae with viscoelastic

Fig. 14.30: Stretching the pupil

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existing fibrous tissue but should not damage the sphincter so that the pupil often is functional postoperatively. When viscoelastic is then introduced the pupil will be found to be satisfactorily large. Combined Glaucoma and Cataract Surgery Small incision cataract surgery lends itself very well to combination with glaucoma filtering surgery to produce a safe effective operation, which has little effect on astigmatism. It works particularly well with foldable intraocular lenses, as the wound requires minimal modification. Instruments for the trabeculectomy Vannas scissors, St Martins toothed forceps, bipolar cautery wand, Colibri toothed microsurgical forceps, Alcon angled 3.2 mm phaco slit blade, Crozafon sclerotomy punch, 8/0 Vicryl stitch, micro needle holder. Technique i. A conjunctival flap based on the fornix is formed with St Martins forceps and the Vannas scissors. The conjunctiva is dissected off Tenon’s capsule. This is then dissected from the sclera and removed from the area of the trabeculectomy wound. ii. The scleral vessels are gently cauterised using the bipolar wand. iii. A 4 mm vertical groove is prepared using the slit knife as already described 2 mm behind the anterior limbus. The knife is then turned back to its usual position and a tunnel formed as already described. Phacoemulsification now proceeds normally. iv. After the lens has been inserted and before the viscoelastic has been removed from the eye the Crozafon punch is inserted through the wound. The distal end of the cutter hooks over the edge of the internal part of the tunnel and the punch is closed (Fig. 14.31). The punch is then removed and the tissue in it removed. The sclerotomy is Fig. 14.31: Using the Crozafon punch inspected to see how many bites will be required to produce an adequate opening, this is usually two. The sclerotomy should be about 1mm from the proximal lip of the wound and should leak aqueous gently when it touched with a dry sponge. vi. A small iridectomy is then made and the viscoelastic removed with the I/A. vii. For closure of the wound use 8/0 Vicryl stitches at each end of the conjunctival wound. viii. Inject BSS through the side port and observe the bleb forming.

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White Cataracts These cases are, as already stated in the discussion of capsulorrhexis, very challenging. However even if the rhexis has been satisfactorily accomplished there are still a few points worth noting. When Removing the Nucleus • The nuclei in these cases are often not only hard but very mobile. In order to maximize control during emulsification introduce the manipulator early on to stabilize the nucleus. This is particularly important when sculpting. Note Use of a chopping technique is not recommended in these cases because the capsule can be difficult to see when the chopper is passed to the equator and it is thus easily damaged. • There is little if any epinucleus or cortex to protect the posterior capsule in the presence of sharp nuclear fragments. Use the same precautions as mentioned in relation to hard cataracts. EPINUCLEUS

REMOVAL

The main points in relation to persistent epinucleus have already been discussed under the section on soft cataracts. However if there is a bowl of epinucleus as sometimes occurs with no break in the edge it can present the surgeon with some difficulty. Here are some suggestions: • Use the nucleus manipulator to go out to the equator of the capsular bag to pull the epinucleus centrally • If this does not work the manipulator can be used to divide the edge and allow the phaco tip to occlude on one side • Finally if all else fails and the epinucleus refuses to cooperate use viscoelastic to get under the edge and lift it centrally for aspiration. IRRIGATION/ASPIRATION I/A Handpieces The bimanual irrigation/aspiration handpieces considerably facilitate cortical removal, particularly that found subincisionally. The advantage of cortical cleaving hydrodissection is that there is relatively little cortex left to aspirate. Machine settings Both Alcon Legacy and AMO Prestige—Maximum vacuum 400+ mmHg, linear aspiration flow 24 ml/min. Technique Occlusion of the aspiration port is all important to achieve efficient cortical removal. Once this has happened the cortex can be dragged centrally for aspiration. i. Begin the cortical removal with the irrigation in the left hand and the aspiration in the right. The deep chamber produced by the closed wounds will help considerably the removal from the fornices of the capsular bag. Aspirate

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Fig. 14.32: Bimanual irrigation/aspiration facilitates cortical removal

CAPSULAR

CLEANING

all that is easily accessible with one hand and then simply change hands to reach the rest. Sub-incisional cortex used to present particular problems and was a common reason for capsular breaks during I/A. Note If any cortex does not come easily for whatever reason, leave it in situ until later. When the viscoelastic is injected prior to lens implantation it is used to viscodissect the remaining cortex. The lens is then implanted and with the protection of the posterior capsule by the IOL, the already loosened cortex is easily removed with the I/A (Fig. 14.32).

There are sometimes remnants of cortical material which need to be removed from the posterior capsule prior to lens implantation. They can either be polished off using a Kratz scratcher or similar to abrade the capsule gently or be aspirated off with the I/A in low vacuum mode. If these remnants are not removed they can lead to early capsular wrinkling. Capsule Polishing Instruments

Kratz scratcher on irrigation handpiece with free flow irrigation.

Technique A circular movement is used on the capsule and a halo reflex from the posterior capsule indicates the correct plane. There is no feeling of contact with the capsule, this is a visual technique. Vacuuming the Capsule Instruments I/A handpiece with phaco machine set with vacuum at 35 mmHg and aspiration rate at 16 cc/min. Technique With settings on the machine at this low level the posterior capsule can be safely picked up in the I/A port with little or no risk of its breaking. Residual cortex and plaque can often be aspirated off by this means. If there is persistent plaque, which does not polish off or cannot be aspirated from the posterior capsule either it can be left (for 3 months) for later YAG laser capsulotomy or posterior capsulorrhexis should be considered. This technique allows more rapid visual rehabilitation than delayed YAG but there are a few surgical points to be considered before undertaking it. Posterior

Capsulorrhexis

Instruments Straight cystitome as used for anterior capsulorrhexis mounted on viscoelastic syringe, capsulorrhexis forceps.

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Technique i. The cystitome is introduced and the anterior chamber gently filled with viscoelastic. Do not overfill the eye as it will put too much tension on the capsule. ii. The tip of the cystitome engages the capsule (Fig. 14.33) centrally and produces a small tear. In young patients with elastic capsules this can prove surprisingly difficult. Viscoelastic is injected slowly under the posterior capsule to push back the vitreous face. Fig. 14.33: Starting the posterior iii. The capsulorrhexis forceps grasps the torn capsulorrhexis edge of the capsule and the tear is started. The posterior capsule is much more diaphanous than the anterior and also more elastic (Fig. 14.34). Producing the posterior rhexis seems to require more pull than the anterior. Aim to produce a posterior rhexis 2/3 of the size of the anterior. Note It is important to make sure that the rhexis is truly completed, if it has a radial break at the edge this can spread when the IOL is placed in the bag. When it is anticipated that there may be anterior capsular epithelial cell growth across the anterior hyaloid, an anterior vitrectomy followed by pushing the IOL through the posterior rhexis should be considered (Fig. 14.35). INTRAOCULAR

LENS

IMPLANTATION

General Consideration Viscoelastic The eye will need to be refilled with viscoelastic prior to implantation, currently I use Provisc. It is important, particularly with a folding lens, to make sure that the capsular bag is well distended and the anterior chamber is also deep. This

Fig. 14.34: Tearing the diaphanous posterior capsule

Fig. 14.35: Posterior chamber lens through posterior capsulorrhexis

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will allow easy placement of the IOL and its unfolding with minimum trauma to the ocular contents. Wound Sizing In small incision cataract surgery there is now a bewildering array of lenses available in a variety of materials. Some folding lenses can be implanted through unenlarged wounds, often however some adjustment of the wound will be necessary. The folding lens, which I currently use, is the Alcon MA60 or MA30 Acrysof. The former will pass easily through a 3.5 mm opening, the latter through 3.2 mm. The phaco slit knife can be used to ease the edge of the wound and thus enlarge it sufficiently. Lens Implant At present I use only Alcon AcrySof for all cataracts except high myopes where the dioptric range is not available. I have stopped using PMMA because it does not fold and therefore denies my taking an advantage of small incision. Silicone I will no longer use because although on the whole my results were good, the capsular effects and occasional foreign body reaction in the eye are not satisfactory. PolyHEMA I like as a material and have been involved in trials of a new design of lens made of this material. However it is as good as Acrysof in terms of capsular opacity and YAG laser rates. My own experience of acrylic is now 8 years, the results in visual terms as well as the very low capsulotomy rate are impressive. This material also works very well in compromised eyes with uveitis, glaucoma, diabetes, etc. The size of the MA60 and three-piece design mean that it can be used also as a backup lens and the gentle unfolding of acrylic allows insertion folded even with a capsular break. The lack of capsular contraction that this IOL produces permits me to insert it safely into the bag in the presence of a capsulorrhexis break with little risk of decentration. Implantation Instruments Angled McPherson forceps, Seibel folding paddles, Duckworth and Kent (Buratto) insertion forceps, Colibri microsurgical forceps, lens dialing hook. Technique

i. Open the wagon wheel container for the lens and ask the nurse to squirt BSS on to the lens. Note This material is affected by temperature in that if the lens is too cold it is harder to fold. It is best if available to place it in a warming cabinet. ii. Move the microscope away from the eye and reduce the magnification. With the McPherson forceps place the lens on the back of the wagon wheel case. iii. Take the Seibel paddles and open them press down on the edge of the lens to make sure their is no meniscus of BSS underneath it and fold the lens. This done by closing the paddle forceps having placed the lens in the

CURRENT PHACOEMULSIFICATION TECHNIQUES

Fig. 14.36: Folding the lens with paddle forceps

iv. v. vi.

vii.

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Fig. 14.37: Gripping the lens with the Buratto forceps

grooves on the inside of the paddles (Fig. 14.36). The lens can be folded either from 6 to 12 or 3 to 9. The author prefers the 6 to 12 fold. Down the microscope check that the lens has folded in half rather than asymmetrically which would impair implantation. With the Buratto forceps grasp the lens along the top of the paddles (Fig. 14.37). Turn the lens so that the straight edge of the folded optic faces the left. This will mean that the haptic which turns on unfolding is outside of the eye not in the capsular bag. Introduce the distal haptic to the wound which is gripped by the Colibri forceps and allow it to form a D-shape (Fig. 14.38). Push the optic gently into the eye. As the haptic releases on entering the eye dip the forceps down to place the distal haptic in the bag. With the optic now in the eye the hand is rotated so the folded spine of the IOL is superior (Fig. 14.39). The lens is squeezed gently and then released (Fig. 14.40). Normally it drops down into the bag and slowly unfolds. The Buratto forceps can then be removed from the eye.

Fig. 14.38: Introducing the distal haptic

Fig. 14.39: Rotate the lens

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Fig. 14.40: Release the lens

Fig. 14.41: Rotating the lens into the bag

Note If the lens does not release cleanly rapidly squeeze it again and release again, because of the slow unfolding the forceps can be released faster than the lens regains its unfolded shape. viii. The lens dialing hook now enters the eye and is used to push the optic into the bag if it is not there already and then with a gentle rotary movement the lens and its trailing haptic are dialed into the capsular bag (Fig. 14.41). The AcrySof MA30 is introduced similarly but it an also be implanted with two injecting systems one is disposable (Alcon Monarch) (Fig. 14.42) the other reusable (Duckworth and Kent)(Fig. 14.43). VISCOELASTIC Instruments removal.

REMOVAL

I/A handpieces with machine set at same settings as for cortical

Technique The I/A handpieces are introduced into the eye and aspiration is commenced over the center of the optic. The irrigation port can be pushed onto the optic to encourage viscoelastic to come around the IOL and into the anterior chamber for aspiration It is possible to observe down the microscope the viscoelastic disappearing down the I/A port.

Fig. 14.42: Alcon Monarch injecting system

Fig. 14.43: Duckworth and Kent breech loading injector

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CLOSURE

Closing the Self-Sealing Wound Technique The hydrodissection cannula attached to a syringe filled with BSS is placed in the side port incision and the eye reinflated so that it feels quite firm when the center of the cornea is pressed. If the wound is still leaking stromal hydration can be useful. The endothelial pump starts to work within a few minutes of the end of the procedure. The watertightness of the wound is tested by placing a dry sponge posterior to the wound and pressing. It should remain dry. In the vast majority of cases a suture is not required because the tunnel wound and its internal valve close satisfactorily. If the surgery has been complicated and the IOL has been inserted unfolded or when tested with a sponge the wound has not sealed properly a suture will be placed. Suturing the Wound Instruments Colibri toothed microsurgical forceps, micro needle holder, Alcon 10/0 nylon suture CU1 needle. Technique With viscoelastic in the eye to retain its firmness, the lip of the wound is lifted with the Colibri forceps. A horizontal pass is made with the needle along the bed of the wound from right to left. The needle is now passed through the upper part of the tunnel from inside out. It is reinserted through the outside of the tunnel again and into the wound to create a horizontal mattress stitch. This is tied into the wound (Fig. 14.43) and the ends trimmed. No great tension is needed on the stitch as it generally is acting only to buttress the tunnel. FINAL

CONSIDERATIONS

The conjunctiva is picked up and cefuroxime is injected subconjunctivally. The drape is then removed and a shield placed over the eye. Postoperatively the patient receives one bottle of G Maxitrol to be instilled 4 times daily for 2 weeks and then twice daily until it is finished.

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Steve A Arshinoff

Phaco Slice and Separate*

15

INTRODUCTION Techniques of dividing the cataractous lens into smaller pieces for easier phacoemulsification have been evolving since Kelman first introduced Christmas tree capsulotomy in association with sculpting and cracking, in 1967.1 Gimbel was the first to propose a formalized “technique” with “divide and conquer nucleofractis”, 2 which many others later modified according to their own preferences.3-7 Nagahara’s 1993 technique of phaco chop,8 was popular, but difficult, due to its need for a very large capsulorrhexis and for the surgeon to reach out to the periphery of the lens, under the capsulorrhexis with the phaco chopper. Paul Koch overcame this problem with “stop and chop” one year later.9 More recently, in 1995, H. Fukasaku introduced “snap and split phaco”, which has the advantages of eliminating both sculpting and the need to go out to the periphery with any instruments.10 Fukasaku’s technique has not gained wide acceptance due to its need for the surgeon to exert considerable stress on the nucleus to achieve a snap, a step that many surgeons are not prepared to adopt, and also because the technique works best on lenses more dense, and therefore more brittle, than those usually encountered in many practices. The author devised the technique of “phaco slice and separate” after studying and trying those of Fukasaku and the others mentioned above. Slice and Separate was first presented at the annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS) on April 26, 1997, in Boston, Massachusets, and published in the Journal of Cataract and Refractive Surgery in April, 1999.11 The * Reprinted with changes, with permission from J Cataract Refract Surgery 25:474-78,1999.

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author’s technique was changed from those of his predecessors, above, to achieve 5 goals which the author felt were not adequately achieved with previous techniques: • Permit all of the work to be done in the central 3 to 5 mm of the lens, thus making the technique safer, and directly applicable to small pupil phaco surgery. • Divide the lens in a manner to minimize zonular stress, thus increasing safety, especially for cases of pseudoexfoliation, or postvitrectomy cataracts. • Completely eliminate sculpting, which is inefficient and may cause excessive zonular stress, particularly in very dense nuclear cataracts. • Reduce phaco time to a minimum, thus making the procedure more endothelial cell friendly. • Make the procedure relatively independent of nuclear density, so that the surgeon does not have to significantly vary the approach to the lens from case to case, thus reducing complication rates. Method The technique is illustrated in Figures 15.1A to H, and a detailed description of issues pertinent to nuclear disassembly is given below. Preoperative patient preparation, anesthesia, incision, and other surgical steps are only mentioned where materially different in this procedure compared to other common cataract techniques. Hydrodissection Cortical cleaving hydrodissection is achieved, as taught by Fine,12 using balanced salt solution in a 6 cc syringe with a 27-gauge hockey stick cannula. Meticulous hydrodissection is essential to this technique, as frequent nuclear rotation is required. Consequently, the author usually does it twice: once injecting the balanced salt solution (BSS) under the nasal lip of the capsulorrhexis, and again under the temporal lip. He then checks for nuclear freedom by slight gentle nuclear rotation with the hockey stick cannula. GETTING

READY

TO

SLICE

In all chopping techniques, the anterior lens cortex can obstruct visibility and is gently phacoemulsified off by encircling the inside edge of the capsulorrhexis with the phaco before proceeding to slice and separate. This step also helps cortical removal because it creates an even frilly cortical edge at the capsulorrhexis margin which assists in the aspiration of any residual cortex. No phacoemulsification is done inside the eye until both the phaco tip and the Nagahara chopper (Asico #AE2515) are secure inside the anterior chamber (to stabilize the eye), and the phaco is run on I/A for a few seconds to clear some central viscoelastic, permitting free fluid flow. The

First

Slice

The first slice is the most difficult and most critical. The Nagahara chopper tip is gently placed against the nucleus just inside the capsulorrhexis lip proximal to the incision, and the nucleus is nudged distally. The phaco tip, which is already

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Fig. 15.1A: The procedure does not require access to the periphery of the lens, and consequently is illustrated here with a mid-dilated pupil. The first step is meticulous cortical cleaving hydrodissection, followed by removal of the cortex covering the nucleus, in the area of the capsulorrhexis, so that nuclear manipulation does not become visually obstructed by floating cortex

Fig. 15.1B: Phaco “Slice and Separate” is illustrated for a right handed surgeon. It is begun by impaling the nucleus with the phaco tip to stabilize it, followed by inserting the Nagahara chopper into the nucleus, to its full depth, just inside the distal margin of the capsulorrhexis

Fig. 15.1C: The Nagahara chopper is drawn, just to the left side, and past the phaco tip, in a slicing motion, to divide the lens in half. Brittle harder lenses will develop propagation of the slice, sometimes even before the chopper gets to the phaco tip, but softer, less brittle lenses may require the slice to be carried through to the proximal margin of the capsulorrhexis

Fig. 15.1D: The chopper is then reinserted into the slice, beside the phaco tip, and the 2 halves of the lens are separated to effectively achieve peripheral cortical as well as nuclear separation

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Fig. 15.1E: The nucleus is rotated clockwise about 30 degrees, and a second slice is made in the distal nuclear half. In order to attain satisfactory depth with the phaco tip, it is often necessary to traverse part of the proximal nuclear half with the phaco, for the first two or three slices

Fig. 15.1F: The sliced piece is then separated from the remaining part of the distal heminucleus to achieve good cortical separation. The posterior capsule usually becomes visable with this maneuver, beginning with the second slice

Fig. 15.1G: The lens is again rotated and slicing and separating repeated. Removal of the nuclear pieces can be begun at any time. Sometimes it is easier to remove one of the first pieces to create working space, but sometimes, if the separations are more difficult to achieve, it is easier to slice up the entire nucleus before removing any piece

Fig. 15.1H: Usually the second, or later, piece of pie is removed first, because separations of the pie pieces becomes cleaner as the procedure progresses. Once a space is opened up, when a piece has been removed, the subsequent slices become easier, and are merely continued all around

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in the eye, is now buried into the nucleus, aiming just to the right of and beyond (if the phaco is being held in the right hand) the geographic center of the nucleus (central in depth as well), making sure that the anterior surface of the phaco needle stops below the nuclear surface. In the author’s experience, this is optimally achieved with the phaco machine set on linear pulse, about 5 per second, with a 50% duty cycle. The vacuum is set at about 150 mm Hg using a peristaltic pump and standard sized needle (however the Alcon ABS smaller needles require vacuum of about 275 mm Hg). If the vacuum is set too high, the phaco will tend to erode through the nucleus, rather than stabilizing it. It is easier to achieve nuclear stabilization if the silicone sleeve of the phaco needle is recessed from the tip 3 to 4 mm, rather than the more customary 2 to 3 mm, because it is not desirable for the irrigation port to enter the nuclear tunnel created by the phaco needle. Thirty, fifteen, or zero degree phaco needles may be used, with the author’s own preference being the 30 degree tip, because it is able to be easily occluded to achieve slicing, but the emulsification of the segment is not slowed as it is significantly with the steeper angled tips. Furthermore the 30 degree angulation of the needle aperture roughly equals the entry angle of the phaco needle into the nucleus, resulting in the needle opening pointing directly inferiorly in the lens during surgery. The Nagahara chopper is now inserted into the nucleus just inside the distal edge of the capsulorrhexis. In more dense nuclei, this is not always that easy. It may be facilitated by tilting the chopper upwards, so that it enters the nucleus with the sharp edge leading, in a rotatory downward movement, not straight down. The chopper enters the lens and is moved progressively deeper as it is pulled just to the left side of the phaco tip. If the phaco needle has not been advanced far enough, the lens will tend to rotate when the chopper is inserted and drawn toward the phaco tip. If this occurs, just phaco in a bit further. In softer, less brittle nuclei, the slice will not spontaneously propagate proximally as slicing progresses, and as a consequence the chopper must be drawn past the side of the phaco tip, often as far as the proximal capsulorrhexis edge. In that case, the chopper must then be replaced adjacent to the end of the phaco tip, in the slice, before separation is attempted,. The separation is better if rotation in opposite directions, rather than simply pulling, is used, because rotation causes the distal nucleus and cortex to separate into two first, and continuing the rotation causes the separation to propagate proximally. In harder, more brittle nuclei, the same is done, but in this case, the slice tends to spontaneously propagate as the chopper approaches the phaco tip, thus obviating the need to go past the phaco tip with the chopper, and making medium density nuclei the easiest cases. In very dense nuclei, it is sometimes difficult to get the chopper deep enough into the nucleus to achieve through and through slicing. If this occurs, after passing the chopper through the nucleus, do not attempt to separate, just return and slice again in the same trough in order to achieve adequate depth of penetration of the chopper. Occasionally, especially when the technique is new to a surgeon, the first slice is incomplete, or not in the originally planned direction. This is usually due to the surgeon’s fear of going too deep, something that is actually very difficult to do. If incomplete separation occurs, do not worry, just go on to the successive

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slices. Each successive slice is easier than the last, and it does not really matter how the nucleus is sliced, as long as the pieces are small enough to be easily emulsified. The Second and Subsequent Slices The second slice is easier than the first, because a central depression has already been made in the nucleus, and so it is easier to get deeper with the second entry of the phaco, and easier to judge how deep you are. After completion of the first slice the Nagahara chopper is inserted distally into the trough and the nucleus is rotated about one and one half clock hours clockwise (right-handed surgeon). The phaco is then inserted into the distal half of the nucleus, at its right side, about one half or less clock hour from the edge, sometimes traversing the distal aspect of the proximal nuclear half in order to attain sufficient depth. The distal half is stabilized on the phaco tip, exactly as above, and the Nagahara chopper is used to create a second slice, just at the left edge of the phaco tip, in the same manner as above. Good separation is achieved, again by rotation in opposite directions. Because the first slice is the most difficult, it is wise not to aspirate this first liberated pie piece first, as it may still be attached to the right heminucleus. It is rather preferable to repeat the steps of rotation and slicing again once, a few times, or until the whole nucleus has been sliced up, before removing any pieces. The pieces are easily aspirated and emulsified by using the chopper to separate the pieces not being removed toward the left, while rotating the phaco which is holding the piece to be aspirated, to the right, thus creating ample space to aspirate out the first and subsequent pieces. Rotation of the lens pieces is easily achieved with the phaco chopper, which has a blunt rounded tip. The surgeon should, however be sure that the phaco machine is irrigating, so that the posterior capsule is taut, and not curled around the phaco chopper, when nuclear rotation is performed. Sometimes a shelf is created with the first slice. This occurs if the phaco chopper was not inserted to full depth, and slicing therefore did not go down to the center of the lens, and the deep half of the lens was just pulled apart without any guiding slice. If this occurs, it becomes difficult to extract the nuclear pieces on one side because they are partially wrapped around a shelf of nucleus. This is resolved by just completing all of the slices around the nucleus until you get to one that is easy to remove. The rest just follow in succession. Further facilitation is achieved by going through the accidentally created nuclear shelf with the phaco, as successive pie pieces are grasped for slicing. Completing the Procedure Once the nucleus has been sliced, emulsified and aspirated, irrigation/aspiration of residual cortex is done in a standard fashion. The posterior capsule is then vacuumed. An additional posterior capsule cleaning trick that the author likes is to use a 6 cc syringe of BSS and a hockey stick cannula. If the cannula is allowed to be placed tangential to the plane of the posterior capsule, and the BSS is ejected in puffs, allowing the capsule to come up around the hockey stick tip between puffs, the low viscosity of BSS (1.0 mPs) causes excellent dissection of the cortical material remaining, off the posterior capsule.

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The capsular bag and anterior chamber are then inflated with viscoelastic, the incision enlarged if needed to accommodate the intended IOL, and the IOL inserted. Viscoelastic is then removed using the authors rock and roll technique. 13 ,14 Finally, vancomycin 1 mg/0.1 cc is injected through the side port. The incision and side port are checked for leakage. SUMMARY Phaco slice and separate is the most gentle technique of phacoemulsification that the author has ever tried. It never requires any instrument to be placed out beyond the boundary of the capsulorrhexis, and consequently is very safe, and a good technique for small pupil cases. Because the nucleus is stabilized on the phaco tip before any stressful action is performed, it is also excellent for cases of pseudoexfoliation or lenticular instability or subluxation. It does, however, require a bit different mind set from older techniques of phacoemulsification, because of the lack of a sculpting step, and having to deal with multiple slices simultaneously. This change may require surgeons to take a bit of time to get used to seeing and understanding what is happening during the case. The effort, however, soon is rewarded by smoother surgery, with less concern for nuclear density and pupil size, and fewer complications. With experience, the simplification of surgery, due to the fact that the technique is relatively independent of nuclear density, pupil size and lenticular stability, makes the surgeon’s day in the operating room run much more smoothly and significantly reduces the risk of complications. REFERENCES 1. Kelman CD: Phacoemulsification and aspiration—a new technique of cataract removal (a preliminary report). Am J Ophthalmol 64: 23-35, 1967. 2. Gimbel HV: Divide and conquer nucleofractis phacoemulsification—development and variations. J Cataract Refract Surg 17:281-89, 1991. 3. Davison JA: Minimal lift-multiple rotation technique for capsular bag phacoemulsification and intraocular lens fixation. J Cataract Refract Surg 14:25-34, 1988. 4. Shepherd John R: In situ fracture. J Cataract Refract Surg 16:436-40, 1990. 5. Fine IH: The chip and flip phacoemulsification technique. J Cataract Refract Surg 17:366-71, 1991. 6. Pacifico Ronald L: Divide and conquer phacoemulsification—one handed variant. J Cataract Refract Surg 18:513-17, 1992. 7. Fine IH, Maloney WF, Dillman DM: Crack and flip phacoemulsification technique. J Cataract Refract Surg 19:797-802, 1993. 8. Nagahara K: Phaco-chop technique eliminates central sculpting and allows faster, safer phaco. Ocular Surgery News October 12-13, 1993. 9. Koch PS, Katzen LE: Stop and chop phacoemulsification. J Cataract Refract Surg 20:566-70, 1994. 10. Fukasaku H: Phaco snap phacoemulsification. Alcon Video Film Festival. American Society of Cataract and Refractive Surgery Annual Meeting San Diego, California, 1-5, 1995. 11. Arshinoff Steve A: Phaco slice and separate. J Cataract Refract Surg 25(4): 474-78, 1999. 12. Fine IH: Cortical cleaving hydrodissection. J Cataract Refract Surg 18:508-12, 1992. 13. Arshinoff Steve A: Rock ‘n’ Roll Removal of Healon GV. Alcon video film festival. American Society of Cataract and Refractive Surgery Annual Meeting, Seattle, Washington. June 1-5, 1996. 14. Arshinoff Steve A: Rock ‘n’ Roll Removal of Healon GV. In Arshinoff Steve A (Ed): Proceedings of the 7th Annual National Ophthalmic Speakers Program (Ottawa, Canada, June 1996). Medicopea 1997.

Eric J Arnott

Cataract Extraction and Lens Implantation: The Implosion Technique

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INTRODUCTION There have been more changes in cataract surgery over the last five decades than occurred over the previous three millennia. In the West the intracapsular was changed to the extracapsular cataract extraction (ECCE) in the mid 1970s, and over the last two decades this has been superseded by the phacoemulsification of the cataractous lens. In the world as a whole, these progressive changes have swept over the continents like a tidal wave. While in the USA some 97% of cataracts are performed using the ultrasonic technique, in the UK the figure is 50% and in the Asian countries some 10%. In both of these latter areas, the percentage of operations performed using ultrasound or laser, for cataract surgery, will increase over the years until “the small incision removal of the cataractous lens with insertion of an intracapsular lens implant” becomes the standard procedure. Various factors have militated against the more rapid adoption of phacoemulsification as the standard cataract operation. Not least are the expensive surgical machinery required for its performance and the surgeons learning curve in adopting this procedure. Another important consideration is the general state of the eye and adnexa, with its cataractous lens, in the Third World, as compared to the eye with a cataract in the Western world. In Asian countries poverty, malnutrition, disease and adverse climatic conditions will often present the surgeon with a cataractous eye that cannot easily be treated with small incision cataract surgery. The Asian eye with its adnexa may have scarring of the lids, conjunctiva and cornea; resulting in an eye, which has contracted lids, misplaced lashes and a sunken immobile globe. Moreover the cornea may be semiopaque and the pupil small and non-dilatable.

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In the event of an eye with a cataract that requires surgery, the presence of poor exposure and a fixed small pupil, may influence the surgeon to consider doing an extracapsular procedure rather than phacoemulsification. The majority of Asian cataracts are mature with a brunescent nucleus, whereas most Western cataracts are relatively immature. Current technology and newer techniques of surgery are enabling surgeons to do phacoemulsification on lenses with very dense nuclei, which would have been considered impossible some years ago. While the lens with a dense nucleus may be more difficult to phaco than a softer cataract it does have the advantage of being more brittle which makes its splitting and chopping easier. Just as in cataract surgery there has been a shift from intracapsular to extracapsular and finally phacoemulsification, so in “phaco” itself there has been a progressive change in the procedure. In the original operation as described by Charles Kelman in 1968 the anterior capsule was opened with a”Christmas tree” configuration and the nucleus was dislocated into the anterior chamber of the eye, prior to phacoemulsification. The opening into the anterior capsule was modified into a “can-opener” by Robert Sinskey et al in 1972. With this larger opening in the anterior capsule, the nucleus could be phacoemulsified in the posterior chamber. In 1987 Howard Gimble and Thomas Neuhnann introduced the concept of capsulorrhexis of the anterior capsule, with a circular tear opening being made. While considerably improving the surgical procedure, since it allowed a lens implant to be inserted totally within the confines of the capsular bag, it did cause some problems with the phacoemulsification of the nucleus. In the older techniques, the larger opening in the anterior capsule gave greater access for the removal of the nucleus. In the presence of a capsulorrhexis the surgeon had a much more limited access to the nucleus. This led to the introduction of advanced “phaco” procedures such as “divide and conquer”. For its removal the lens was divided and emulsified. The implosion procedure is a variant means of phacoemulsifying the nucleus in the presence of a capsulorrhexis. The Surgical Approach The eye for surgery is prepared with mydriatic drops to dilute the pupil and antibiotic guttae to kill any bacteria lying in the conjunctiva and fornices. A steridrape covers the lashes and a lid speculum exposes the globe (Fig. 16.1). The Incision

Fig. 16.1

The incision into the eye may be made using, either the clear corneal or scleral tunnel approach (Fig. 16.2). The clear corneal incision described by Eric Arnott in 1975 and remodified by Howard Fine in 1992 may be either one or two step in style. It is made either in the corneal meridian with the steepest slope or

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Fig. 16.2

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Fig. 16.3

in the lateral meridian at 3 O’clock in the left eye and 9 O’clock in the right eye. A diamond keratome of some 3.2 mm width is used (Fig. 16.3) If the scleral tunnel approach is to be used the incision is usually made in the 12 O’clock meridian. The opening into the anterior chamber is microscopic some 3.2 mm in cord width and three step in configuration, giving a water type seal at the end of the operation. The initial incisions some 300 microns in depth [the tissue at the corneoscleral junction being some 700 microns in thickness] are made either at the corneoscleral junction or just posterior to it, in the sclera. From the depth of this incision a lamella split is made extending anteriorly into clear cornea for some 2 mm; the plane of this incision being parallel to the iris-lens diaphragm. From the anterior limit of this second portion of the section the anterior chamber is entered using a 3.2 mm keratome; this penetration being at right angles to the second part of the incision. When the tip of the keratome has just perforated into the anterior chamber it is pointed towards the apical anterior surface of the lens. In this way a self-sealing incision is obtained. Reconstitution of AC with Viscoelastic Solution A Wycroft cannula on a syringe filled with viscoelastic solution is inserted into the anterior chamber and passed over the anterior surface of the lens to lie just within the pupillary margin in the 6 O’clock meridian. In filling the anterior chamber with this viscoelastic solution the aqueous humor is replaced, further pupillary dilation may be achieved, the anterior surface of the lens is flattened, and a protective layer is coated over the corneal endothelium. Capsulorrhexis A capsulorrhexis is performed, creating a round hole some 5.5 mm in the elastic cuticular anterior capsule (Fig. 16.4). This

Fig. 16.4

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Fig. 16.5

Fig. 16.6

is one of the most important and precise part of the operation. The anterior capsule of the lens is perforated with a bent needle tip placed at the midpoint of the anterior capsule. A linear tear is made (Fig. 16.5), the upper edge of which is converted into a flap. This is held with forceps (Fig. 16.6), and with a continuing circular movement and repeated gripping of the torn flap near to the tearing edge, a capsulorrhexis is fashioned. Hydrodissection Before removing the lens contents it is necessary to free the nucleus from the surrounding capsule. The tip of a Wycroft cannula fitted to a 2 ml syringe filled with balanced salt solution (BSS) is placed under the lip of the anterior capsule and a little fluid is injected to flow around Fig. 16.7 the inside of the lens capsule (Fig. 16.7). The tip is moved to different meridians of the edge of the lens capsule each time injecting a little fluid. This has the effect of not only freeing the cortex from the lens capsule but also of washing away some of the equatorial cells; the removal of these germinal cells reduces the incidence of postoperative Elschnig pearl formation. Phacoemulsification of Lens Contents The next stage of the operation is to remove the hard central nucleus with the phaco handpiece tip. The phaco tip is some 1 mm in diameter, with a beveled edge. It is enclosed in a silicone sleeve, which has two side-port holes near its tip. One and a half mm of phaco tip is left exposed beyond the silicone sleeve. While ultrasonic agitation of the tip breaks up the nucleus, bit by bit, fluid enters the eye between the silicone sleeve and the phaco tip.The emulsified debris is aspirated up the phaco titanium tip. Phacoemulsification has been markedly facilitated over the years by progressive improvements in the handpiece. The ultrasonic power, fluid inflow and outflow

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Fig. 16.8

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Fig. 16.9

can be modified according to the surgeon’s needs. The ultrasonic power can be varied from zero to 100 percent. The fluid inflow is normally 25 cu ml per minute but may be increased or reduced by raising or lowering the level of the inflow bottle. The fluid outflow has two parameters—“the vacuum pressure and the aspiration flow rate”. Variants between these two can be used at all stages of the operation. With the “pulsating pump” form of aspirating unit, the vacuum level will not rise within the system until the nucleus or other material occludes the phaco tip. The greater the level at which the aspirating flow rate has been preset, the more rapidly will the vacuum pressure build up once the tip has become occluded. With high aspiration levels there is more followability of the nucleus. There are essentially three different techniques to phacoemulsify the nucleus of the lens. • The divide and conquer • The implosion method • Chop and stop. In most operations with phaco of the nucleus, a deep groove is made from 12 towards 6 over the anterior surface of the nucleus (Fig. 16.8). When making this groove the tip goes deeper towards the center of the nucleus and shallows towards the 6 O’clock meridian (Fig. 16.9), allowing for the convexity of the posterior capsule. While varying power, vacuum and aspirating levels may be chosen depending on the surgeon’s particular needs, average levels for this part of the procedure would be “phaco” power 70%, the vacuum level 60 mm Hg and an aspiration rate of 25 cu ml per minute. The phaco tip shaves the surface of the nucleus, with an action similar to the planing effect of a chisel. The softer the nucleus the deeper the tip may safely penetrate into its substance without disturbing the position of the nucleus, which could put tension on the zonule or capsule of the lens. With a hard nucleus the tip should shave superficially, with only a third or less of its diameter being embedded in its substance. Divide and Conquer In the divide and conquer technique once the initial deep groove has been made a spatula is inserted into the anterior chamber to join the phaco tip. The tips

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Fig. 16.10

Fig. 16.11

of both instruments are placed deep into the groove and with counterpressure against the sides of the groove the nucleus is split into two. These two instruments are next used to rotate the nucleus some 90°. This process is repeated with another groove being made and the nucleus split yet again, so that it has now been divided into 4 quadrants, each of which can be individually emulsified. The vacuum level can be increased at this stage of the procedure to a much higher level. This enables the fragments to be drawn towards the center of the capsular bag where they can be emulsified using low phaco power. The Implosion Method In the implosion technique as with the divide and conquer the initial procedure is to make a deep groove across the anterior surface of the lens .The procedure differs in that the nucleus is not divided prior to its removal but is removed bit by bit in one piece. This has the safety factor in that if the capsule should inadvertently rupture, in an emergency situation, it is easier to deal with one lens fragment rather than multiple pieces of nucleus. The initial deep furrow is debulked on either side leaving intact a rim of nuclear bowl (Figs 16.10 and 11).The phaco tip should at all times be kept in view within the pupil margin in the “safe” triangular area between 4,6, and 8 O’clock. Keeping within this area, only the inferior half of the nucleus can be debulked. Access is gained to the superior half by rotating the nucleus some 90° at which time the debulking process is continued. Further rotation of the nucleus may be required to totally debulk its central contents. When totally debulked the nucleus should resemble a salad bowl with intact rim and inferior nuclear plate (Fig. 16.12). The final part of the “phaco” process is to implode or break off fragments of the nuclear bowl into the cavity of the debulked nucleus, where they can be easily emulsified (Fig. 16.13). Since at this stage of the procedure the more peripheral softer portion of the nucleus is being dealt with, lower power levels may be used, averaging 40%. The vacuum and aspirating levels are left unchanged. This relatively high aspiration rate allows for the phaco tip to manipulate and mobilize the nuclear bowl rim. The tip of the phaco impales the nuclear rim at 3 O’clock causing it to break, implode and rotate into the tip (Fig. 16.14). Due to the “followability” of the

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Fig. 16.12

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Fig. 16.13

lens, the tip placed at 3 O’clock can move along the rim of the nuclear bowl at the same time that the rim is being brought towards the tip. With this combined process the tip can remain within the safe area. The tip can be moved to other areas within the triangle and break up and fragment the remaining portions of the imploding bowl (Figs 16.15 and 16). With the total removal of the nuclear rim only the thin nuclear plate will remain (Fig. 16.17). Removal of this should present no difficulty as it will normally float off the posterior capsule and be simply emulsified (Fig. 16.18).

Fig. 16.14

Fig. 16.15

Fig. 16.16

Fig. 16.17

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Fig. 16.18

Fig. 16.19

The Chop The chop technique may be combined with the “divide and conquer” and “implosion“ procedures or used as a primary procedure. It is best employed in cases with a very hard nucleus, which will be very brittle. High-vacuum pressure up to 200-400 mm Hg may be used. Using this high vacuum and with ultrasonic power the nucleus is impaled near the center of its anterior surface. Once impaled, the vacuum is maintained and the ultrasonic power turned off. A chopping hook is inserted into the anterior chamber and engages the nucleus 1 mm beyond the impaling phaco tip, and drawn towards it. The counterpressure of embedded hook against impaled phaco tip cracks the nucleus. The process can be repeated a number of times breaking the nucleus up into fragments which can be emulsified and aspirated from the capsular bag. It is important to ensure that the hook is at all times within, not over, capsular bag to prevent tension and partial disinsertion of the suspensory ligament of the lens. In the “implosion” technique if the nuclear bowl is particularly hard, the “chop” may be employed to help fracture the rim. Aspiration of Residual Cortex This is performed using the standard irrigating aspirating handpiece with 0.3 mm side port (Fig. 16.19). Lens Implantation With the lens contents removed the capsular bag is now ready to receive the implant. The lens implant may be made of several materials; foldable lenses that go through the phaco incision may be silicone, poly-HEMA (hydroxyethylmethacrylate), or acrylic. Polymethylmethacrylate (PMMA) lenses are more rigid and require the phaco incision to be a little enlarged for their insertion. Most implants have loops, which are attached to the optical portion and contract down when inserted into the capsular bag. Prior to the lens insertion the anterior chamber and capsular bag are filled with a viscoelastic solution. With soft lenses a lens forceps is used to fold over the implant prior to insertion. With the implant folded in the forceps the inferior loop is guided through the

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Fig. 16.20

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Fig. 16.21

section and across the anterior chamber and into the inferior recess of the capsular bag. The forceps now release the lens allowing the optical portion to unfold half in the anterior chamber and half in the capsular bag. The upper loop may be either looped or dialled into the capsular bag. Prior to inserting the PMMA lens the section is enlarged a further 1.75 mm.The insertion is similar to that of a foldable lens except that the lens is inserted in the unfolded state. The lens, held in forceps, is inserted through the section, across the anterior chamber. As with the soft implant the inferior loop is placed in the inferior recess of the capsular bag. A dialling hook is inserted into the upper crutch of the lens, at the junction of optics and loop. With a clockwise dialling motion the upper loop will be corkscrewed into the capsular bag. As an alternative the upper loop lying just within the section may be held with forceps and looped into the capsular bag. The PMMA lens with totally encircling loops has the advantage of giving great stability to the capsular bag (Figs 16.20 and 21). CONCLUSION With this procedure the incidence of postoperative retinal detachments have been reduced from 2.5% with the old intracapsular operation to 0.15% with the small incisional and intercapsular technique. All other complications including late edema of the macula have also been reduced. The small incisional phaco and implant procedure confers other benefits for the patient. The postoperative convalescence is minimal, the patient being able to return to normal activities immediately. A high percentage of visual acuity recovery is regained within the first 24 hrs. The rapid visual rehabilitation, limited postoperative convalescence and reduced postoperative morbidity have markedly changed the indications for cataract surgery.

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Rasik B Vajpayee Tanuj Dada

Phacoemulsification in Special Situations

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INTRODUCTION Phacoemulsification has become the surgery of choice for a cataract extraction all over the world. Although the technique of phacoemulsification is more or less a standard one, there are certain special situations which warrant either a modification of the standard technique or the use of an additional device to facilitate the surgery. Some of these special situations include a small pupil, a subluxated lens, an intumescent lens, anterior uveitis, vitrectomized eyes and the pseudoexfoliation syndrome. Each of these conditions poses a unique intraoperative problem to the surgeon and demands a detailed preoperative planning on how to tackle them. In this chapter we describe the various innovative techniques developed to handle each of these special situations. SMALL PUPIL This is a frequently encountered problem during phacoemulsification. Although endolenticular phacoemulsification can be performed in the presence of a small pupil, it increases the degree of difficulty for the surgeon and is often a cause for complications. There are various intraoperative techniques that can be used to manipulate the size of the pupil, to facilitate phacoemulsification in a miosed pupil. Intracameral Adrenaline The use of 0.1 cc of 1:10,000 adrenaline, injected directly into the anterior chamber through the side port incision, is useful in dilating the pupil. Only preservative

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free drug is to be used. Since the drug is toxic to the endothelium, sodium hyaluronate should be used to coat the corneal endothelium before adrenaline is injected. This is helpful in eyes with an intact dilator pupillae muscle, with no synechiae, fibrosis or hyalinization of the iris musculature. Adrenaline is not to be used in hypertensive or cardiac patients. Iris Hooks Self-retaining iris hooks have been designed by Mackool (titanium) and De Juan (nylon). Three to four hooks are placed through paracentesis sites and the pupil can be widely dilated to a triangular (Fig. 17.1) or square shape. With the use of these hooks, the pupil can be dilated to any size, regardless of the pre-existing pupillary diameter. Although this is an effective technique for pupillary dilatation, it is time consuming, leads to considerable iris manipulation and Fig. 17.1: Three flexible nylon iris retractors being used to dilate the pupil results in a large amount of leakage of fluid from the paracentesis sites. The nylon hooks (Grieshaber and Co) are preferable since these incorporate an adjustable stop which allows the traction on the iris to be manipulated during surgery. Iris Protector Ring Siepser had designed a hydroview iris protector ring (Grieshaber and Co) which can be placed inside the pupil through a 3-mm incision. The ring expands with hydration and gradually ditates the pupil. It is removed at the end of phacoemulsification. Stretch Pupilloplasty This is our personal technique for dilating the pupil. After injecting a high viscosity sodium hyaluronate in the anterior chamber, two Sinskey hooks are employed from two paracentesis sites to engage the inner edge of the pupil. The hooks are placed diagonally opposite each other and then a bimanual stretching of the pupil is done. This stretch is done in the horizontal (3-9 O’clock) and vertical axis (6-12 O’clock) and creates micro tears in the sphincter pupillae, thereby dilating the pupil. A pupil size of up to 6 mm can usually be achieved with this technique. Partial Thickness Sphincterotomies Eight small sphincterotomies are performed using a Rappazzo scissors (used for vitreoretinal surgery) through two side port incisions. The cut is made up to half width of the sphincter pupillae muscle and then a hook is used to stretch the root of the iris in the different meridians in which the sphincterotomies have been made.

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A pupillary size of 6 to 7 mm can be achieved with this method. Postoperative miotic therapy is required to decrease the pupil size and prevent iridocapsular synechiae between the sphincterotomy sites and the anterior edge to the capsulorrhexis. Manipulation with the Chopper The second instrument or the chopper can be employed to stretch the pupil in the area of interest while performing phacoemulsification. The chopper can be placed at the edge of the pupil and the iris manipulated to expose the nucleus that is being currently engaged by the phaco probe. The process is then repeated in the other quadrants till the nucleus is completely emulsified. UVEITIS Anterior uveitis is often associated with a small, bound down pupil with a pupillary membrane and dense posterior synechiae. A fibrinoid reaction with pigment deposition over the surface of the IOL is also a common postoperative problem, specific to cases with uveitis. Phacoemulsification should be attempted only if there has been no sign of activity in the past three months. Preoperative topical and systemic steroids can be started 48 hours prior to the surgery. Since the surgeon often encounters a pupillary membrane in such cases, membrane dissection (a technique first described by Osher) is a prerequisite for pupillary dilatation. In this technique, a bent 26/27 g needle or a capsulorrhexis forceps is used to perform a blunt dissection and stripping of the membrane from the edge of the pupil. After the membrane has been removed the pupil usually dilates to an adequate size for phacoemulsification to be performed. All manipulations in the anterior chamber should be performed under a cohesive viscoelastic like sodium hyaluronate, which also binds to the corneal endothelium and gives protection to the endothelial cells, already compromised due to the intraocular inflammation. Intracameral low molecular weight heparin (Fragmin) can be added in the irrigating fluid (10 IU per ml) to decrease the postoperative reaction. A heparin coated/Smart IOL should be used in such cases, to minimize deposits on the surface of the IOL. SUBLUXATED LENS The stabilization of the capsular bag and implantation of the IOL is an important challenge for the phaco surgeon. If the zonular loss is limited to less than one quadrant a standard phacoemulsification may be attempted safely. If the zonular loss is more extensive, lens manipulation may cause further loss of zonular support and lens dislocation into the vitreous. Although an intracapsular extraction was traditionally performed in such eyes, it is now possible to perform phacoemulsification surgery in a subluxated cataractous lens using the PMMA endocapsular ring (ECR). The ring was introduced by Witschel and Legler in 1993 to provide an intraoperative and postoperative stabilization of the capsular bag. The ring currently in use is

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the one modified by Morcher (Fig. 17.2) and consists of an open, flexible PMMA filament with eyelets present at the open ends. It is dialled with a Sinskey hook (using the eyelets to insert the hook) under the edge of the anterior capsulorrhexis. The ring expands and occupies the equator of the lens, circumferentially distributing the tension inside the capsular bag and thus acting as an artificial zonule. One can then proceed with phacoemulsification using a setting of low flow and low vacuum, to minimize Fig. 17.2: The Morcher turbulence in the anterior chamber and subsequent zonular endocapsular ring stress. Cionni has recently introduced another modification in the ring with the introduction of a separate fixation element or a hook that extends centrally from the ring (Fig. 17.3). At the free end of the hook is an eyelet for manipulation and suture placement, which can be used to allow scleral fixation without disturbing the integrity of the capsular bag. This is helpful in eyes with an extreme loss of zonular support where the endocapsular ring itself may require a scleral support. Since implantation of the IOL may be associated with an excess pressure on the zonules due to the large inflexible PMMA haptics, these haptics can be tied to the surface of the optic using a 10-0 nylon suture prior to insertion into the anterior chamber. The suture can be cut once the Fig. 17.3: The Cionni endocapsular ring IOL is inside the capsular bag for a gentle unrolling of the two haptics. Another method described by Merriam and Sheng makes use of the flexible nylon iris retractors to hook the edge of the anterior capsulorrhexis to support the lens during the surgery. Two to four retractors can be used for this purpose depending upon the degree of subluxation. The retractors are removed at the end of the surgery and while it may be possible to insert one of the haptics in the ciliary sulcus, the second haptic can be sutured to the sclera with a 10-0 prolene suture for better stabilization. POSTVITRECTOMY Cataract development in phakic eyes after a pars plana vitrectomy is a common occurrence, with reported rates as high as 80 to 100% especially if silicone oil has been used. Phacoemulsification in vitrectomized eyes is a difficult task. Poor pupillary dilatation, posterior synechiae, deep anterior chamber requiring a steep angulation of the surgical instruments, zonular damage, posterior capsular plaques, excessively mobile posterior capsule and capsular tears are some of the problems faced by the surgeon. In addition due to absence of the anterior hyaloid, there is loss of posterior lenticular support and alteration in intraocular fluid dynamics. This leads

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a collapse and sagging of the capsular bag during phacoemulsification due to a low vitreous pressure. The use of a superpinky is to be avoided in such eyes and the height of the infusion bottle should be decreased. An infusion port made in the region of the pars plana prior to proceeding with the cataract surgery may prove useful, although this is more relevant to extracapsular cataract extraction (ECCE). The constant inflow of fluid through the infusion cannula maintains a positive vitreous pressure, prevents scleral collapse and allows a comfortable surgery. The infusion port is taken out as the last step during surgery and the sclerotomy port is closed with the preplaced 8-0 Vicryl suture. The integrity of the posterior capsule and the zonules may be disturbed by vitreous surgery. This can lead to a dehiscence of the posterior capsule and zonular dialysis at any time during the phacoemulsification. In such eyes, the endocapsular ring may be required to facilitate a successful IOL implantation. In operated eyes with silicone oil left in the vitreous cavity, a silicone foldable IOL should not be used. INTUMESCENT CATARACT Phacoemulsification in intumescent cataracts is a challenge for the phaco surgery primary because of the difficulty in performing a capsulorrhexis. There is a lack of the red reflex, making the perception of the capsular flap difficult. In addition, since the lens is swollen, there is an increased tension on the anterior capsule and a greater tendency for the margin of the capsulorrhexis to escape towards the periphery of the lens. In such cataracts it is advisable to perform an initial cut in the central capsule to permit escape of the liquid cortex, to decompress the swollen lens. The cortical matter is aspirated out and the anterior chamber filled with a high viscosity viscoelastic substance (Healon GV). Then one proceeds with the capsulorrhexis under condition of high magnification and illumination, using a capsulorrhexis forceps. The surgeon may find it helpful to turn off the light of the operation theater and the microscope, and use an endoilluminator for oblique illumination of the capsule. Another alternative in such cases is to perform the capsulorrhexis under air. This helps to tamponade the egress of liquefied cortical material after an incision in the anterior capsule. A bent 26 g needle is used in performing the capsulorrhexis, if air is to be used. The rhexis forceps requires a large opening and air escapes rapidly if this instrument is used. After completion of the capsulorrhexis, the rest of the procedure is similar to a routine phacoemulsification surgery. PSEUDOEXFOLIATION The pseudoexfoliation syndrome is associated with a weak zonular apparatus with an increased risk of zonular dehiscence during phacoemulsification. Poor pupillary dilatation, a fragile capsule prone to rupture, a degenerated iris, pathological iris vasculature and an increased inflammatory response after surgery are some of the problems encountered in eyes with pseudoexfoliation. The basic tenant of surgery

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in such cases is to minimize stress on the zonules. A number of modifications are suggested to facilitate a smooth phacoemulsification in eyes with pseudoexfoliation. The capsulorrhexis should be done with a Rhein or Utrata forceps, that can pinch the capsule and initiate the tear in the capsule. The needle or cystitome, traditionally used to perform the initial tear on the capsule, exerts much more mechanical pressure on the zonules and there may be a possibility of rupture of the zonules. The endocapsular tension ring and an anterior chamber IOL should be kept in reserve since there is a high incidence of zonular and capsular tears. Hydrodissection should be performed with minimal injection of fluid in several different quadrants to decrease intracapsular pressure. The technique of depressing the nucleus down, to complete the hydrodissection should be avoided. The use of the endocapsular ring offers the safest method of phacoemulsification. The insertion of this ring creates a circumferential distribution of forces around the entire zonular apparatus, thereby reducing the localized pull on the zonules, during any intraocular manipulation. The nucleus should be elevated away from the capsular bag with the second instrument to decrease the zonular traction while manipulating the nucleus in the capsular bag. The implantation of the IOL prior to cortical aspiration is also useful because the PMMA haptics stabilize the capsular bag. In such cases the cortical clean up takes a much longer time and this technique is to be used only if the endocapsular ring is not available. Intense postoperative steroid therapy and adequate cycloplegia may be required to control the postoperative reaction. FURTHER READING 1. Bartholomew RS: Lens displacement associated with pseudocapsular exfoliation—a report on 19 cases in southern Bantu. Br J Ophthalmol 54:744-50, 1970. 2. Carpel EF: Pupillary dilation in eyes with pseudoexfoliation syndrome. Am J Ophthalmol 105:692-94, 1988. 3. Cionni RJ, Osher RH: Endocapsular ring approach to the subluxated cataractous lens. J Cataract Refract Surg 21:245-49, 1995. 4. Cionni RJ, Osher RH: Management of profound zonular dialysis or weakness with a new endocapsular ring designed for scleral fixation. J Cataract Refract Surg 24:1299-1306, 1998. 5. De Juan E Jr, Hickingbotham D: Flexible iris retractor (letter). Am J Ophthalmol 111:776-77, 1991. 6. Eckardt C: Pupillary stretching—a new procedure in vitreous surgery. Retina 5:235-38, 1985. 7. Fischel JD, Wishart MS: Spontaneous complete dislocation of the lens in pseudoexfoliation syndrome. Eur J Implant Refract Surg 7: 31-33, 1995. 8. Fuller DG, Wilson DL: Translimbal iris hook for pupillary dilation during vitreous surgery (letter). Am J Ophthalmol 110:577, 1990. 9. Goder GJ: Our experiences in planned extracapsular cataract extraction in the exfoliation syndrome. Acta Ophthalmol 184(suppl): 126-28, 1988. 10. Grusha YO, Masket S, Miller KM: Phacoemulsification and lens implantation after pars plana vitrectomy. Ophthalmology 1998; 105: 287-94. 11. Hutton WL, Pesacka GA, Fuller DG: Cataract extraction in the diabetic eye after vitrectomy. Am J Ophthalmol 1987; 104: 1-4. 12. Lacalle VD, Garate FJO, Alday NM et al: Phacoemulsification cataract surgery in vitrectomized eyes. J Cataract Refract Surg 24: 806-09, 1998.

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13. Lumme P, Laatikainen L: Exfoliation syndrome and cataract extraction. Am J Ophthalmol 116: 51-55, 1993. 14. McCuen BW II, Hickingbotham D, Tsai M et al: Temporary iris fixation with a micro-iris retractor. Arch Ophthalmol 107:925-27, 1989. 15. McDermott ML, Puklin JE, Abrams GW et al: Phacoemulsification for cataract following pars plana vitrectomy. Ophthalmic Surg Lasers 28: 558-64, 1997. 16. Meldrum ML, Aaderg TM, Patel A, Davis J: Cataract extraction after silicone oil repair of retinal detachments due to necrotizing retinitis. Arch Ophthalmol 114:885-92, 1996. 17. Merriam JC, Zheng L: Iris hooks for phacoemulsification of the subluxated lens. J Cataract Refract Surg 23:1295-97, 1997. 18. Meyers SM, Klein R, Chandra S et al: Unplanned extracapsular cataract extraction in postvitrectomy eyes. Am J Ophthalmol 86:624-26, 1978. 19. Miller KM, Keener GT Jr: Stretch pupilloplsty for small pupil phacoemulsification (letter). Am J Ophthalmol 117:107-08, 1994. 20. Naumann GOH: Exfoliation syndrome as a risk factor for vitreous loss in extracapsular cataract surgery (preliminary report). Acta Ophthalmol 184(suppl): 129-31, 1994. 21. Nichamin LD: Enlarging the pupil for cataract extraction using flexible nylon iris retractors. J Cataract Refract Surg 19:793-96, 1993. 22. Saunders DC, Brown A, Jones NP: Extracapsular cataract extraction after vitrectomy. J Cataract Refract Surg 22: 218-21, 1996. 23. Shepherd DM: The pupil stretch technique for miotic pupils in cataract in cataract surgery. Ophthalmic Surg 24:851-52, 1993. 24. Skuta GL, Parrish RK II, Hodapp E et al: Zonular dialysis during extracapsular cataract extraction in pseudoexfoliation syndrome. Arch Ophthalmol 105:632-34, 1987. 25. Smiddy WE, Stark WJ, Michels RG et al: Cataract extraction after vitrectomy. Ophthalmology 94: 48387, 1987. 26. Sneed S, Parrish RK II, Mandelbaum S, et al: Technical problems of extracapsular cataract extraction after vitreous surgery (letter). Arch Ophthalmol 104: 1126-27, 1986. 27. Whitsett JC, Stewart RH: A new technique for combined cataract/glaucoma procedures in patients on chronic miotics. Ophthalmic Surg 24: 481-85, 1993. 28. Wilbrandt HR, Wilbrandt TH: Pathogenesis and management of the lens-iris diaphragm retropulsion syndrome during phacoemulsification. J Cataract Refract Surg 20: 48-53, 1994.

Jonathan P Ellant

Zen in the Art of Phaco*

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“Like water filling a pond, which is always ready to flow off again, it can work its inexhaustible power because it is free, and be open to everything because it is empty.” —Zen in the Art of Archery, by Eugen Herrigel Throughout my training it became apparent to me that most of the phaco surgeons that I assisted were comfortable with only one or two different techniques to remove the nucleus of a cataract. And as I watched dozens of surgeons, they all seemed to use the same one or two techniques. It quickly became clear to me that situations arise in which one’s standard technique is either more risky or less efficient when compared with other alternative approaches to nucleus removal. I wanted to learn as many phaco techniques as possible, so as a resident I tried to watch as many different surgical videotapes as I could get my hands on. Like most surgeons, I also have one or two techniques with which I am most comfortable, and that I use most often. But, I try to remain as flexible as possible during the case and alter my technique as the individual case may dictate. In this chapter I will progress step by step through a phacoemulsification case and try to elucidate some of the situations that these alternative techniques may be useful. I perform my routine case with a temporal hinged clear corneal incision, with continuous curvilinear capsulorrhexis (CCC), and hydrodissection and hydrodelineation though the original incision. I then utilize in the bag divide and conquer nucleofractis techniques as described by Howard Gimbel.1 This is then followed by automated I/A and foldable three-piece IOL placement in the bag. However, *

I would like to thank Howard Gimbel and Richard Mackool for the generous use of their slides

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when situations arise that are not routine, I do not hesitate to alter my technique and use one which is safer or more efficient. Incision As I stated, I routinely use a temporal hinged clear corneal incision. When properly created this incision is refractively neutral, stable and easy to perform. Furthermore, it preserves the conjunctiva in case glaucoma filtering procedures need to be performed in the future and is bloodless which is particularly important for patients taking anticoagulants or aspirin. When a patient has greater than 1.25 diopters of with-the-rule (WTR) or oblique astigmatism, I move my incision toward the steep axis and depending on the axis and degree of astigmatism I decide where to place the incision. When the astigmatism is greater than 45 degrees away from the horizontal meridian, I use a corneoscleral tunnel; usually, this results in a more or less superior corneoscleral incision. Viscoelastic Much has been written about the advantage of one viscoelastic over another. Recently a great deal of research has begun to quantify the precise differences in cohesiveness between the different agents.2 Routinely I will use one of the agents that is in the middle of the cohesive/dispersive spectrum. However, in a patient with significant endothelial dysfunction I am careful to select an agent that is more dispersive. I want this viscoelastic to coat the endothelium as well as possible and to remain in the eye to protect the endothelium throughout the case. Cohesive agents tend to be removed in a bolus during phacoemulsification and do not adequately protect the compromised endothelial cells. In those cases where I use a more dispersive agent, I take a few extra seconds at the end of the case to try to remove any residual viscoelastic that may remain in the eye. Capsulorrhexis Continuous curvilinear capsulorrhexis has elegantly transformed the way in which cataract extraction is performed.3 It is arguably the critical step which will determine the ultimate success of the phacoemulsification and IOL placement. Before beginning the CCC, I inject additional viscoelastic into the anterior chamber to try to enlarge the pupil and to flatten the anterior capsule. At this point it is wise to evaluate the adequacy of pupillary dilation. Good dilation of the pupil is very important for safe and efficient phacoemulsification. I have observed extremely talented individuals perform CCC in eyes with small pupils with the leading edge of the rhexis under the pupil, essentially unseen. While this is a most impressive maneuver, I do not recommend it for mere mortals such as myself. I believe that for most of us this is just asking for trouble, and there is not much more trouble than a radial extension of the CCC at this point in the case. I have found that pupil stretching techniques to be extremely useful when the pupil is small.4 I use a bimanual technique with an iris hook through the

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original incision and a Kuglein manipulator through the side port incision. Occasionally I create an additional paracentesis incision approximately 120 degrees away from the main incision on the side opposite the original paracentesis incision for cases where extensive posterior synechiae are present. In these extreme cases I also use the viscoelastic with its cannula to viscodissect the synechiae. It is very unusual to not obtain adequate pupillary dilation after carefully engaging segments of the pupillary margin 180 degrees from each other with these two (or two similar) instruments and moving the two opposite one another, toward the direction of the trabecular meshwork. The two instruments are then moved to different areas of the pupillary margin and the action is repeated, three or four times is usually adequate. Occasionally, small hemorrhages may occur at the pupillary margin, they are self-limited however, and resolve without any further treatment. Additional viscoelastic is then instilled into the eye to evaluate the adequacy of the pupil dilation. Stretching can be repeated if necessary, but care must be taken to avoid damaging the anterior capsule during any iris manipulation. Several devices have been developed to facilitate dilation including the Beehler pupil dilator and disposable iris retractors. I used the latter during my residency and found them to be quite useful, now however, I rarely use anything other than the technique described above. Minisphincterotomies may also be performed, however these significantly disrupt the blood-aqueous barrier and seem overly traumatic in my view. However, cases may exist where they are necessary and one should keep this option in mind. I usually begin the CCC with a cystitome, and continue it with capsulorrhexis forceps, aiming for a 5 mm opening, or slightly smaller than the optic. If one is seeking additional efficiency, the capsulorrhexis forceps may be used to initiate and complete the CCC.5 During the rhexis I observe the lens for any phacodenesis or zonular dialysis, if any is observed I change my mindset. This is a situation where having flexibility and the knowledge of alternate techniques enables one to perform safer surgery and avoid potentially significant complications. When loss of zonular integrity is recognized, I create a larger CCC, and alter my technique, planning to prolapse the nucleus during hydrodelineation, and perform supracapsular phacoemulsification of the nucleus.6 In this way, one may reduce stress on an already compromised zonular apparatus and complete the case without disinserting more of the zonules. White nuclei and hypermature nuclei present special challenges because no red reflex is present and visualization of the leading edge of the capsular tear is extremely difficult. Many different techniques have been described, including the injection of intracapsular fluorescein, capsule staining with trypan blue, side illumination (with a flashlight or similar illumination device), reducing the overhead lighting, and endoscopic illumination.7-9 In these cases I usually turn off the room lights and increase the magnification of the microscope. I then attempt a smaller than normal CCC (approximately 3-4 mm). By reducing the diameter I am able to increase my margin of error, should the CCC begin to extend radially. The CCC can then be enlarged secondarily after removal of the cataract and implantation of the IOL.10 At times

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it is not possible to successfully perform an intact CCC in these cases. When the rhexis begins to extend radially, one may have to convert to a can-opener type capsulotomy for the remainder of the circle. If this occurs, additional care must be taken during hydrodissection and phacoemulsification to prevent a radial tear from being created. One should again consider supracapsular phaco in this instance. After IOL implantation it is occasionally possible to convert the can-opener portion of the capsulotomy to a continuous tear for additional IOL stability and centration.10 CCC in hypermature or Morgagnian lenses can sometimes be performed with relative ease with the use of a little trick. Occasionally after the initial puncture of the anterior capsule in these cases, liquefied cortical material may leak into the anterior chamber and obstruct one’s view. If this occurs after the anterior capsule is pierced with a cystitome, one can place a 27-gauge cannula on an empty syringe, place the tip of the cannula through the opening created in the capsule, into the anterior cortex and aspirate some of the liquefied cortex. Usually the anterior chamber must be re-expanded with additional viscoelastic. After sufficient amounts of cortex have been aspirated, a red reflex is often seen and a careful CCC may be performed in the usual manner.11 Hydrodissection and Hydrodelineation These two steps are extremely important, both to preserve the zonules and to facilitate removal of the nucleus and cortex. I begin using a J-shaped cannula for subincisional hydrodissection. This has proved to be of invaluable assistance to me in removal of subincisional cortex. I then proceed with standard hydrodissection and hydrodelineation using a straight cannula (Fig. 18.1). Before attempting any phacoemulsification, I will use the cannula Fig. 18.1: Hydrodissection tip or a cyclodialysis spatula to rotate the nucleus to ensure that adequate hydrodissection has been performed. Nucleus Removal Numerous techniques have been described, but as I mentioned in the introduction, most surgeons utilize few of them. The more techniques that one is aware of, the more flexible and efficient one can be when intraoperative challenges present themselves. No matter how many techniques one knows, there will always be one or two that are most familiar and with which one has the most experience. I believe that as one obtains more experience, it is possible to use subtle maneuvers to encourage the cataract to behave as one wants it to, but until that time, knowledge of alternative techniques, and the flexibility to use them, will enable the beginning or intermediate phaco surgeon to handle challenging cases with greater safety

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and efficiency. I will try not to describe all of the different techniques in detail, as they are covered in other chapters in this book and elsewhere.12 Routinely, I use the divide and conquer nucleofractis technique. I learned this technique during my fellowship with Howard Gimbel and while it is more difficult to learn and master than the widely used four-quadrant technique described by John Shepherd, I believe that it offers greater opportunity for flexibility and efficiency, especially when intraoperative challenges arise. In addition, it lends itself especially well to eyes with small pupils and to converting to phaco chop and stop and chop in cases with denser nuclei.13-14 Soft Nuclei Standard divide and conquer techniques may be used, but in younger patients with posterior subcapsular cataracts or in diabetic patients it is often difficult to perform complete fractures in these softer nuclei. As a result it is often necessary to sculpt out a large central bowl of nuclear material, with a very thin posterior plate, and then to fold the nuclear rim in on itself. These cases can sometimes be some of the most difficult to complete without compromising the posterior capsule. Extreme care must be used when sculpting deeply. I advocate generous use of viscoelastic to reposition nuclear elements centrally so that they may be emulsified within the safer central zone in the space created by the capsulorrhexis opening. Occasionally, when attempting to engage the nuclear rim, one has not thinned the posterior plate adequately and is unable to affect a fold. If too much of the nuclear rim is removed the standard “bowl” technique will not work because there is insufficient nuclear rim to grasp with the phaco probe. Placing viscoelastic beneath the posterior plate may displace the remaining posterior nuclear fragment into the safe central zone for emulsification. Alternatively, if the inferior rim has been removed, and enough of the superior rim and adjacent areas still remain, the second instrument (cyclodialysis spatula) can be used to gently nudge the posterior plate inferiorly to allow the phaco probe to engage the superior rim just inside the proximal edge of the capsulorrhexis and enable the surgeon to remove the remaining cataract (Fig. 18.2).15

Fig. 18.2: Eccentric capsulorrhexis and bidirectional phaco

Fig. 18.3: The initial trench

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Moderately Dense Nuclei This group of lenses represents the bulk of the cataracts that the average phaco surgeon will encounter. As stated previously, I routinely use divide and conquer nucleofractis.1 In this technique, one begins with the sculpting of a deep central trench just slightly off center, toward the side of one’s dominant hand (Fig. 18.3). I have found down-slope sculpting to be extremely useful in cases without zonular compromise (Fig. 18.4).16 After sufficient depth is obtained the second instrument (i.e. cyclodialysis spatula) is placed deep within the trench adjacent to the phaco probe and the two instruments are positioned on opposite walls of the groove and moved away from each other to crack the nucleus into hemisections (Fig. 18.5). It has been my observation that most surgeons sculpt further into the periphery than is necessary. This is both dangerous and inefficient. When the initial sculpting of the trench is sufficiently deep, it is rarely necessary to sculpt beyond the rim of the capsulorrhexis opening to facilitate complete and consistent cracking.

Fig. 18.4: Down-slope sculpting

Fig. 18.5: The initial fracture

After a small rotation of the nucleus, the phaco probe is used to burrow into the inferior section of the nucleus with a short burst of ultrasonic power. Next, using foot position two on the phaco machine, aspiration is used to engage and stabilize the nucleus. The second instrument is held adjacent to the phaco probe and using a small down and away movement with the second instrument, the phaco probe breaks off a pie-shaped fragment (Fig. 18.6). One may think of this maneuver as similar to phaco chop in attempting to visualize the required hand movements. However, the two instruments are moved away from one another rather than toward each other as with phaco chop. The lens is then rotated and the fracturing maneuver is performed again. This is repeated several times until the cataract is broken into multiple wedge-shaped fragments (Fig. 18.7). These are then engaged with the phaco handpiece and emulsified in the safe central area of the capsular bag, approximately at the level of the capsulorrhexis opening.12

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Fig. 18.7: Pie-shaped segments

Dense Nuclei In these lenses a variation on the trench technique is used. Deep central sculpting is used to create a central crater with the phaco probe, deep enough to thin the posterior plate sufficiently to facilitate cracking (Fig. 18.8). The inferior portion of the nuclear rim is engaged with a burst of phaco energy and the second instrument is used to create a fracture, as described above (Fig. 18.9). The lens is then rotated and the nucleofractis technique is repeated until the lens is completely divided into wedge-shaped pieces. Each wedge is then drawn centrally and emulsified.17

Fig. 18.8: Crater divide and conquer

Fig. 18.9: Removal of a nuclear segment

Recently, I have been increasing my use of the phaco chop technique in these cases (Fig. 18.10). Chopping is a very efficient technique for nuclear division, particularly in dense lenses.13-14 Care must be taken, however, to preserve the anterior capsular rim. Because phaco chop puts the capsule at some additional risk so, I reserve the technique for denser nuclei or for cases with compromised zonules.

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Early identification of this event is critical to a good outcome. Initially, when one recognizes a small tear in the posterior capsule, a dispersive viscoelastic should be injected through the tear, in an attempt to keep the vitreous face from prolapsing through the defect in the posterior capsule. When the tear is small, it is sometimes possible to engage the tear with a capsulorrhexis forceps and create a posterior capsulorrhexis. This will stabilize the defect and prevent it from Fig. 18.10: Phaco chop enlarging.18-19 If a large portion of the nucleus is still present in the eye and the rupture is small, one may occasionally rotate the remaining nucleus over the rent (using the nuclear segment to block the defect), and emulsification may continue more or less as before. In this situation, phaco chop may allow more efficient disassembly of the nucleus, minimizing total phaco energy and turbulence. An alternative method involves the use of a sheets glide placed over the capsular opening to create a “pseudo-posterior capsule.”In either of these situations extreme care should be exercised to prevent prolapse of the vitreous into the capsular space. Lowering both the bottle height and the aspiration flow rate will reduce turbulence in the eye and reduce the chance of vitreous prolapse. If large fragments exist one may attempt to engage the lens with the phaco probe and prolapse the nucleus into the anterior chamber where phaco chop may be used to divide the remaining nucleus and remove it from the eye. However, one should use extra care to avoid “post-occlusion surges” as these may increase the incidence of prolapse of vitreous. Once vitreous prolapse is recognized, phacoemulsification should be stopped and one should attempt to manually remove the remaining fragments through the main incision followed by careful and complete anterior vitrectomy. One should consider conversion to an extracapsular extraction at this point if the remaining nuclear segments cannot be safely removed through the original incision. IOL Insertion I routinely use foldable IOLs through a slightly enlarged clear corneal incision. However, I alter the lens that I use depending on the individual needs of the patient. For example, larger optics for diabetics and younger patients or those with large pupils, or acrylic lenses for patients with an increased probability of needing silicone oil and vitrectomy in the future (diabetics and patients with HIV/AIDS). After IOL insertion, if I notice that a tear in the anterior capsule has occurred, I place a small matching incision 180 degrees away in the anterior capsule in the hope of balancing capsular contraction forces and maintaining IOL centration.11

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If zonular dehiscence has occurred, the IOL can be rotated so that the orientation of one of the haptics is toward the area of the dehiscence using the haptic to push the area of the capsule with the dehiscence back toward its original anatomic location. A PMMA capsular tension ring has been developed by Morcher and has been used with much success for this same purpose.20 Unfortunately, till now of this writing the ring has still not obtained FDA approval for use in the United States. In the case of severe zonular dialysis or loss of large amount of posterior capsule alternative approaches become necessary. These include the placement of an anterior chamber lens, a sulcus-fixated lens (with or without optic capture to facilitate IOL centration), and the suturing of a posterior chamber IOL.21-24 CONCLUSION The ability to recognize and to manage complications during surgery and to have good outcomes is what separates excellent from average surgeons. The willingness to teach oneself a variety of techniques and to understand the most appropriate occasions to use them is very important if one hopes to become a competent phaco specialist. Just as important however, is to be flexible enough to depart from one’s most comfortable techniques and to utilize new approaches to reduce complications and to properly manage them, so as to maximize the visual potential of the patient. When a surgeon has knowledge of many different techniques of nuclear removal and the flexibility to use them, it becomes possible to use phacoemulsification and small incision surgery for even the most dense and complicated cataract cases that one may encounter. REFERENCES 1. Gimbel HV: Divide and conquer nucleofractis phacoemulsification, development and variations. J Cataract Refract Surg 17:281-91, 1991. 2. Arshinoff SA: Dispersive-cohesive viscoelastic soft shell technique. J Cataract Refract Surg 25:16773, 1999. 3. Gimbel HV, Neuhann T: Developments, advantages, and methods of the continuous curvilinear capsulorrhexis technique. J Cataract Refract Surg 16:31-37, 1990. 4. Koch P, Davidson JA: Advanced Phacoemulsification Slack: Thorofare, 1991. 5. Gimbel HV, Kaye GB: Forceps-puncture continuous curvilinear capsulorrhexis. J Cataract Refract Surg 23:473-75, 1997. 6. Maloney WF, Dillman DM, Nichamin LD: Supracapsular phacoemulsification—a capsule-free posterior chamber approach. J Cataract Refract Surg 23:323-28, 1997. 7. Hoffer KJ, McFarland JE: Intracameral subcapsular fluorscein staining for improved visualization during capsulorrhexis in mature cataracts (letter). J Cataract Refract Surg 19:566, 1993. 8. Nahra D, Castilla M: Fluorescein-stained capsulorrhexis (letter). J Cataract Refract Surg 24:1169, 1998. 9. Melles GRJ, De Waard PW, Pameyer JH et al: Trypan blue capsule staining to visualize the capsulorrhexis in cataract surgery. J Cataract Refract Surg 25:7-9, 1999. 10. Gimbel HV, Willersheidt AB: What to do with the limited view. J Cataract Refract Surg 19:65761, 1993. 11. Gimbel HV, Chin PK, Ellant JP: Capsulorrhexis. Ophthalmol Clin North Am 4:441-55, 1995. 12. Gimbel HV, Ellant JP, Chin PK: Divide and conquer nucleofractis. Ophthalmol Clin North Am 4:45769, 1995.

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13. Koch PS, Katzen LE: Stop and chop phacoemulsification. J Cataract Refract Surg 20:566-70, 1994. 14. Koch PS: The stop and chop phacoemulsification technique. Ophthalmol Clin North Am 4: 497507. 15. Mackool RJ: Eccentric capsulorrhexis and bidirectional endocapsular phacoemulsification. J Cataract Refract Surg 17:221-32, 1991. 16. Gimbel HV: Downslope sculpting. J Cataract Refract Surg 18:614-18, 1992. 17. Gimbel HV: Trough and crater divide and conquer nucleofractis techniques. Eur J Implant Refract Surg 3:123-26, 1991. 18. Castaneda VE, Legler UFC, Tsai JC et al: Posterior continuous curvilinear capsulorrhexis—an experimental study with clinical applications. Ophthalmology 99:45-50, 1992. 19. Gimbel HV: Posterior capsule tears using phacoemulsification—causes, prevention, and management. Eur J Implant Refract Surg 2:63-69, 1990. 20. Cionni RJ, Osher RH:Management of profound zonular dialysis or weakness with a new endocapsular ring designed for scleral fixation. J Cataract Refract Surg 24:1299-1306, 1998. 21. Uthoff D, Teichmann KD: Secondary implantation of scleral-fixated intraocular lenses. J Cataract Refract Surg 24:945-50, 1998. 22. Oshima Y, Oida H, Emi K: Transscleral fixation of acrylic intraocular lenses in the absence of capsular support through 3.5 mm self-sealing incisions. J Cataract Refract Surg 24: 1223-29, 1998. 23. Neuhann T, Neuhann TH: The rhexis-fixation lens. Film ASCRS, 1991. 24. Lyle WA, Jin JC: Secondary intraocular lens implantation—anterior chamber vs posterior chamber lenses. Ophthalmic Surg 24:375-81, 1993.

Keiki R Mehta

My Personal Technique of Vertical “Hubbing” Phacoemulsification

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PREOPERATIVE PREPARATION The pati ent is dilated with 5% Neo-Synephrine eyedrops with 1 percent homatropine eyedrops. Both the drops are commenced 40 minutes prior surgery. In case the pupil is tardy in dilatation, place a drop of methylcellulose on the cornea, instill a drop of Neo-Synephrine and homatropine on it, lift the lid and shut it over the methylcellulose, tape the eye shut for 5 minutes. Usually after that period, the pupil is well dilated. Another alternate technique to dilate a tardy pupil is to instill a drop of Xylocaine 4%, and then to instill the dilating drops. It functions as the epithelial cells’ closed junctions become tenuous, permitting easier diffusion into the anterior chamber of the dilating drops. I also favor preoperatively treating the patient with a topical antibiotic-NSAID (nonsteroidal antiinflammatory drug) combination for a day prior surgery. The rationale for it is that surgical insult is much less likely to demonstrate any postoperative inflammation. In addition the use of preoperative antibiotics to reduce the risk of postoperative endophthalmitis. ANESTHESIA TECHNIQUE Topical anesthesia is my choice for 98 percent of all cataract surgeries. I use topically, Xylocaine 4% eyedrops (Lidocaine). The Xylocaine is drawn in two syringes through a Millipore (20 micron) filter. One syringe is left outside the operating field to be used prior draping and washing the patient, and kept with the circulating nurse. The second sterile syringe is left on the operating trolley after clearly labeling it. A drop is instilled three minutes prior surgery so that the eye may be washed out with Betadine solution (5% Betadine mixed with distilled water in a 50% dilution).

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After washing the eye out, a final drop of Xylocaine is instilled on the cornea prior commencing the case. Normally topical anesthesia is all that I use in virtually all cases. However, if intraoperatively the patient has a problem and the case is likely to take longer (inadvertent vitreous loss, a complaining patient, one who keeps rotating his or her eye like a metronome, etc) I also keep a 5 ml syringe with 2% Xylocard (intravenous Xylocaine, preservative free, normally used by the cardiologists) with a blunt parabulbar cannula. All syringes are plastic, disposable and Luer-Lok type. At that stage it is a simple procedure to give 1.00 ml as a parabulbar injection. It is virtually painless, no pressure needs to be applied to the eye to diffuse the anesthetic agent, and takes effect almost immediately. Though the movement of the eye will take about a minute or so to decrease and stabilize down, the anesthetic agent takes effect almost immediately. I normally like to instill a final drop of 4% Xylocaine after the lid retractor has been placed, just prior starting. I lift the retractors just a little to enable the drop to go all the way up to the fornix. Wait for about 30 seconds, wash off the eye with BSS and commence surgery. I normally do not use the Xylocaine 4% drops again at all. In the younger anxious patients or in those in whom I am not sure of achieving their full cooperation, a little sedation is given intravenously. The amount of sedation being such that the patient does not drop of to sleep but just becomes a little more amenable to control. I like my patients to be able to respond to commands during the surgery. In those cases which need further supplementation, I/V Propofol administered in 10 mg increments induces a transient hypnosis with amnesia which clears rapidly in minutes. In cases where the papillary dilatation is inadequate, despite best efforts at dilatation of the pupil, and where intracameral surgical manipulations will involve iris touch, or in cases where I would intend to use iris retractors (Grieshaber), I like to inject little Xylocard 2% (preservative free Xylocaine) diluted 50% with BSS, to convert it to Xylocard 1%, 0.5 ml injected immediately after the side port opening is made, prior injection of viscoelastic. Wait for a minute, wash out the chamber, and proceed with the surgery. It reduces the iris sensitivity and reduces ciliary proprioception (Grabow). I also like to use intracameral Xylocard in cases where the cataract is very hard and where the surgery is likely to last much longer with more ultrasound energy in the anterior chamber and much more lens manipulation. I am a little hesitant to use topical anesthesia with patients who I cannot converse with during the surgery, like mentally retarded patients, or even patient speaking a language which I am not familiar with. In these patients, I prefer to give a peribulbar injection of 2% Xylocaine with 150 units of hyaluronidase admixed, a single injection administered through a 24 G, 1 inch disposable needle, the injection given through the upper lid. I feel it is important when giving the peribulbar block to insert the tip of the index finger between the orbital ridge of the frontal bone and the eye, which deflects the eyeball away. The patient is requested to look straight upwards at the operating microscope light (visible through the closed lid), and the injection

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of 3.00 ml is given at the point 1/3 towards the nasal point of a line drawn between the two canthi. No massage is given. The eye is taped shut (to prevent accidental corneal abrasion) and the balancing weights (Tony Fernandez, 1992) are placed on the eye. I personally do not prefer to use either Honan Oculopressor, the Super Pinky ball as I feel that in cases of an inadvertent venous leak by a slow hemorrhage in the socket, the pressure induced is likely to compromise the ocular circulation. The balancing weights balls are safer since they are not a constrictive device. The pressure from the balancing balls, is kept on the eye for 5 minutes, the IOP is checked with the Schiotz tonometer. The ideal pressure should be a minimum of 10 deflection using no weight (5.5 gm). The patient should be made comfortable on the operating table. It is preferable that the hands be loosely restrained so that accidentally during the procedure in case the patient falls asleep and suddenly awakes, he should not move his hands up and make an unexpected moment. PREFERRED PHACOEMULSIFIER My present personal choice is the Legacy 20,000 (Alcon). The Alcon Legacy has exceptional fluidics, maintains the chamber well, has excellent ultrasound power, with a sensitive, balanced, stable, 4 crystal handpiece, rarely induces bubble formation and works very well. I usually use the Max-Vac setup with a, 30 degree, 0.9 mm diameter, straight tips which work very well on the hard cataracts common in India. The Kelman 30 degree bent, 0.9 mm tip also works well but sometimes a bit unpredictable. Perhaps the biggest advantage of the Kelman is that, since the tip is curved down, the surgeon does not need to hold the handpiece at a steep angle. The Legacy has superior followability making the procedure much simpler. In addition the dynamic range of fluidics allow the surgeon to really individualize settings at every single phase of cataract removal depending upon the grade of the nucleus. DRAPING AND PREOPERATIVE PREPARATION OF THE EYE The patient’s eye is washed out with 10 ml of Betadine 5% solution diluted with distilled, sterile water (not tap), half and half (50% dilution), taken in a 10 ml plastic syringe. The assistant keeps the lids open widely to permit a proper wash. Subsequently cotton swabs soaked in full strength Betadine, are swept along the lash line to be sure that the lashes are clean and properly prepared. Next the entire area of the eye is again flushed out with distilled water, dried with a sterile towel. Two drops of an antibiotic solution are instilled in the eye (at present I use tobramycin eyedrops). A highly adherent plastic drape, termed as Opsite (Johnson and Johnson) Tegaderm (3M) which is commonly used to isolate the skin for surgical procedures, is placed over the fully opened eye such that it drapes the lashes, deflected outwards and away from the field, and drapes all crevices around the eye and the surrounding area. It is important that there should be adequate oxygenation under the drapes. An ideal device to maintain it are silicone nasal prongs. The tubes are looped around

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the ear to stabilize them and the prongs placed in the nostrils. Oxygen (of if not available, even normal air) at a flow rate of 8 volumes/minute. It is very reassuring to the patient to feel air under the drapes which otherwise may make a patient very apprehensive and asphyxiated. In addition it assures adequate oxygenation which is very useful to a patient who has limited respiratory ability (asthmatics or those with chronic pulmonary conditions.) Over the draped eye, a second self-adhesive drape can be utilized, and over that a sterile, absorbent, thick cotton drape with a small hole is fitted over. The head is draped in a double layer of cloth to isolate the forehead and the face away from the site to be operated. It is important to tape a piece of rolled absorbent gauze just in front of the ear on the operating side so accidentally water does not trickle in the ear during surgery, leading to discomfort and sudden head movement. The normal eye (the one not to be operated) is taped shut, gauze placed on it and a protective plastic shield taped over it. The tape directly on the eye is to prevent the gauge from irritating it, and the shield is to protect the eye in case, accidentally the surgeon does apply inadvertent pressure, which may cause the patient discomfort and again may be the cause for the patient fidgeting under the drapes. MONITORING PATIENTS IN THE THEATER I strongly feel that all patients, even if they are under topical anesthesia must be suitably monitored in the theatre. All my patients have a finger-probe oxygen saturation monitor with simultaneous cardiac monitoring. A safety intravenous line is commenced with a 23G Vent-Flo (silicone indwelling venous catheter) which is much more stable and safer than a butterfly venous needle, which tends to be displaced at the slightest movement. I use an anesthesiologist as a standby in all cases. He normally only gives the I/V antibiotics on the table and monitors the patient, but gives supplementary sedation and analgesics if required. In the balance salt solution (BSS plus, considering its high cost, is not really required for short procedures unless the endothelial cell count is significantly low) is added ½ ml of a cardiac, preservative free, epinephrine 1/1000 (without sodium bisulfate) instilled in a 500 ml bottle to maintain the dilatation of the pupil, and to keep a good clean, bloodless field. In addition to the 500 ml bottle of BSS add 10 mg of vancomycin or 40 mg of garamycin. The use of these antibiotics, in my opinion, significantly reduces the risk of endophthalmitis. Other authorities too concur (Linda Strong, 1999, Kraff, Gills 1999). A final drop of Xylocaine is added and the procedure is now commenced. I do not like to utilize more drops as Xylocaine 4% used excessively will lead to punctate epithelial keratitis, corneal erosion and a delayed postoperative rehabilitation, and is said to lead to endothelial cell damage (Marr WG, Wood R 1957). I prefer also to connect dual BSS bottles, connected to each other and to the phacomachine by a thick walled ¾ cm bored, plastic tubing (normally used by Urologists, it is known as a TUR set). The advantage of using this tubing is that

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it gives a good flow and cuts down on surge developing which is critical in the high flow techniques used (Bangkok system). In addition in the BSS bottles the airways are special long needles which reach right up to the clear air space on top rather than being put in below. It is important for the suction generated in a glass bottle to suck in the air very often leads to fluidic imbalance and suction variables especially if one is operating at low suction near the capsule or in removing the final little bit of cortical or cortex material. OPERATIVE PROCEDURE The patient is requested to look into the operating light and advised that he keeps his eye stable and fixed at the light. It is clearly explained to him that at the time phaco is done he must not move at all. The operating light intensity is kept low until such time that Phacoemulsification is commenced. The plastic drape is incised, and a reversible spring speculum is utilized to give the eyes open. An ideal speculum is the Kratz modified, Barraquer speculum. The spring speculum is preferable to fixed screw speculums, because it has a certain amount of ‘give’ which enhances patient comfort. Another advantage is that with a flexible spring retractor the patient does not fight it. He blinks a few times, tiring the orbicularis, and then keeps the eye wide open. THE INCISIONS A side port incision is made with a Alcon V-lance blade (1.2 mm spear) (Fig. 19.1), made with the blade as parallel to the cornea as possible to get a good self-sealing shelf. The chamber is refilled with BSS from a 3 ml syringe to reform the chamber and repressure the eye in preparation for the main phaco incision. Almost all my implants utilized are Fig. 19.1: Side port being made flexible and in most of the cases a SI40 Allergan silicone foldable lens inserted via an injector (Unfolder in Allerganese), which goes through a 2.8 mm incision. Hence, virtually all my cases have a pure corneal tunnel. In case I will put in a PMMA 5.25 mm IOL, I prefer to do a semiscleral incision in a curved ‘V or chevron ’ incision after reflecting back the conjunctival flap. CORNEAL ENTRY The correct point of entry is posterior to the clear cornea, utilizing the perilimbal capillary plexus as a landmark and slightly anterior to the insertion of the conjunctiva (Fig. 19.2). I always prefer to see a faint capillary bleed where I make my entry. Since the incision is into a slightly vascular area, better long-term wound healing

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can be expected rather than a incision into clear cornea. The clear corneal entry can be done in a two-plane incision or in a single-plane incision. However, the single plane incision is best done with the special diamond knife which has a bevel on the blade which is more pronounced anterior than posterior (Fine). Here the diamond knife is placed on the cornea, and following the corneal plane inserted straight in without any Fig. 19.2: Clear corneal tunnel incision attempt at dimpling the cornea. Due to the variance in the front and back bevel of the knife, it enters in smoothly, at the proper plane, and gives an excellent corneal valve. I normally utilize this 2.8 mm diamond, angled keratome (3-D Rhein). In the two-plane entry system, the first incision is placed perpendicular to the corneal plane. I prefer to place the first plane of entry at 10.00 O’clock position. Rather than directly entering into the cornea I prefer to make a shallow groove with the sharp edge of the knife and equal in length to the blade’s width. Care is taken not to incise the conjunctiva, as this will result in conjunctival ballooning during phacoemulsification and during irrigation-aspiration, markedly reducing visibility. The second plane, which essentially creates the cleavage in the corneal stroma and creates the corneal flap valve, is created by placing the shaft (the flat surface) of the blade in apposition with the conjunctiva and advancing in the plane of the cornea. When one had advanced by 2.0 to 2.5 mm, the tip of the diamond knife is turned forwards till it dimples the deeper layer of the cornea. The knife is then allowed to go its full depth creating a perfect rectangular and almost square incision. Dimpling is not required with the Rhein 3D knife with the anterior differential bevel as it automatically enters. Removal of the knife from the eye is equally important. Many a good valve has been ruined by incising the edge during removal of the knife. It is important not to lift the knife during removal but to gradually slide it out in the same plane that it was inserted. It is important to try and attain a perfect square inner entry zone. The characteristics of the flap valve stability depend more on the construction of the inner corneal valve and less on the total width or length of the incision as is commonly thought. If premature tip entry takes place, do not let it continue. Remove the knife and change the position of the entry. Alternatively even the same site can be used but make the knife enter a corneal plane more superficial than the last one. The new incision will tamponade the old one. The incision when finally made, should be 2.8 mm in width and 2.00 mm in length which gives exceptionally good stability. If a 5.25 mm width narrow profile phaco PMMA IOL lenses is to be used, ideally the incision should be a square, but a 5.25 by 4.00 mm length incision usually suffices.

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The position of the placement of the main phaco incisions is identical in both eyes, namely at the 10.00 O’clock position. If for any reason this site is not appropriate due to a very deep set eye or a prominent forehead or nose, I like to shift to a temporal approach. The big advantage of a fixed sitting position at the head of the patient is that the position of my surgical assistant, the microscope, anesthesiologist, and instruments lie in their fixed places and do not need to be shifted which often leads to confusion and slows down the pace of surgery. I have found the use of an aspirating speculum (Liebermans) to be a great help. The aspirating speculum is connected to a small dental vacuum pump which gives a low vacuum of 5 to 7 mm of Hg which is more than adequate. THE CAPSULORRHEXIS My personal preference is to utilize a sharp tipped forceps to do the rhexis in preference to a needle.(26 G, ¾” length) with its tip bent at a 45° angle (Figs 19.3 to 5). The sharp tipped needle, though it has the advantage that one can enter through a closed chamber, lacks control in hypermature cataracts, marbled cataracts (where the anterior capsule has a differentially thickened capsule, as typically occurs in old, neglected cataracts), or in eyes where the pupil is not fully dilated. On the other hand, where the capsule is thick and leathery, especially in young children, or is lax where there is doubt about zonular integrity, it would make more sense to do a needle rhexis.

Fig. 19.3: Circumcorneal capsulorrhexis

Fig. 19.4: Circumcorneal capsulorrhexis

Via the phaco corneal tunnel entry zone, the anterior chamber is re-formed with viscoelastic. I normally like to use methylcellulose which is frozen. Methylcellulose kept in the compartment just below the freezer increases its density by a factor of three. The frozen methylcellulose compresses the capsule making rhexis extremely easy. In addition frozen hydroxypropylmethylcellulose (HPMC) does not leak or ooze out easily, and is fantastic for use in children where even Healon does not stay in long. Methylcellulose is available as OccuCoat (Storz) in USA and other countries, and in India as Visilon, Hyprosol, Moisol and a host of others. AmVisc Plus (Alcon) is also a good viscoelastic which can be utilized, however it is quite

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costly for the Indian situation. Healon, by itself has no place in phacoemulsification surgery as it promptly jumps out the moment the phaco tip goes in. However Healon 5, functions well, and is very useful, though prohibitively priced. In doing a forceps capsulorrhexis, I prefer to make the incision in the capsule using the sharp pointed tips itself. The initial opening is made at 5.00 O’clock, about 2.5 mm inferior, measuring from the Fig. 19.5: Circumcorneal capsulorrhexis center of the lens simply opening a mm in size. Closing the rhexis sharp pointed forceps makes a beautiful little nick in the capsule. Once the nick is made, the capsule is caught in the tips of rhexis forceps, which are then moved to the left in a counterclockwise direction, towards the 11.00 O’clock position. The forceps leaves the previous hold and takes a fresh hold at the tip of the rhexis tear, and the forceps is then swung to towards the 6.00 O’clock position, until it reaches the 8. 00 O’clock position when it is re-held and then gradually swung in such a way that it meets the previous rhexis opening from out, On an average three holds and re-holds are adequate for a good, well controlled rhexis peripherally. Doing a rhexis is like taking a dog for a walk. One needs to pull its direction at right angle to the prompt direction to change it to the new line. If a needle rhexis is desired, I prefer to make the initial capsular opening with a 26 G, ¾ inch needle, performing the initial capsular opening at the 6. 00 O’clock position about 3.00 mm peripherally to the center. The initial opening is made by impaling the needle tip and pulling down, to the 12.00 O’clock position for about a mm and then swinging it to the right to the 3.00 O’clock position, in one smooth maneuver. This simple arc-shaped movement will give rise to a well-positioned flap. The next step is to lay the flap onto the capsule. The point of the needle must be used to move the detached flap in a plane with the residual capsule. Try not to dig it in the capsule. The whole secret is to nudge the capsule along. Since the flap lies in apposition there is no chances of a sudden breakout and often control is better. Be sure to turn the flap, around till it reaches more peripheral to the place where it began and turn it in the meet the origin of the rhexis. The correct shape after completion would, thus resembles an apple. Ideally rhexis is best done under a viscoelastic though it can also be done under BSS and even under air. Viscoelastic has the advantage that it keeps the chamber well formed and tamponades the capsule. If HPMC is used as a viscoelastic substance, it works even better as frozen methylcellulose (kept in the last shelf, below the freezer compartment) as it does not flow out easily, and tamponades the capsule perfectly, maintaining the chamber deep, even in a tight eye.

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Both air- and BSS-based rhexis can only done with the needle. Using a forceps and opening up the chamber lead to a disastrous collapse of the chamber and even inadvertent contact of the delicate endothelium and the rhexis instrument. In both BSS and an air-based rhexis, the rhexis has to be done before the phaco corneal tunnel is made, so that it is complicated in a totally sealed chamber. If the phaco entry incision has been made prior rhexis, it is safer and better, to use a third incision site for doing the rhexis. Using BSS-filled chamber during rhexis is easy, provided a third port is made with a continuous infusion of BSS (Bluementhal cannula), while the procedure is being done. The only problem is that often the flaps floats around and makes it difficult to carry out the procedure. Though, in theory, air is better in an overmature cataract, and the use of BSS based rhexis avoids the use of the viscoelastic, it is always a bit dicey. I always use frozen methylcellulose-assisted forceps-based rhexis. HYDRODISSECTION AND HYDRODELAMINATION Hydrodissection is done utilising a fine, 2426 G flattened cannula with rounded edges (Fig. 19.6), mounted on a Luer Lock 3.00 ml plastic disposable syringe. I always specify Luer Lock since the time I shot a blocked needle in the eye. Fortunately only the capsule broke with no other problems and the patient retained full vision, but it was an experience, difficult to forget. Hydrodissection should be commenced at a point just below the edge of the capFig. 19.6: Hydrodissection at 2’O clock position sulorrhexis. The tip of the hydrodissection cannula should go just under the edge of the rhexis, slightly lift it up, and then inject. This technique is termed as cortical cleaving hydrodissection (Fine 1992). Hydrodissection should be commenced first at 4.00 O’clock position and subsequently at the 7.00 O’clock and finally at 2. 00 O’clock position. Usually by this time the lens seems to move slightly upwards, indicating that the nuclear zone has been hydrodissected off. It is important after every injection to gently compress the center of the nucleus to enable better hydrodissection and prevent central pooling of the liquid and allow the excess liquid to flow out again. It is important to appreciate that hydrodissection in a hard cataract can sometimes give trouble. The surgeon injects, and the moment the fluid is injected, the chamber shallows and, the intraocular pressure (IOP) rises sharply. What has happened is that the fluid has pooled at the back of the lens, as it has no way to exit, and is now pushing the nucleus forward. Any pressure on the lens in an effort to push it back and deepen the chamber will lead to a posterior capsule rupture. At this stage the correct management is to utilize a thin blade iris repositor and insert

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it under the capsular edge at 4.00 O’clock (the site of the primary injection) and sweep it sideways to 8.00 O’clock on the right and to 2.00 O’clock on the left side.. Immediately the fluid will gush out and the eye becomes soft and the chamber automatically deepens. Hydrodelamination as a procedure is now rarely utilized. It was originally conceived as the technique of delineating the hard nucleus and the peripheral epinuclear material. It was in vogue during the four-quadrant grooving technique and was utilized as a method to know how far one could groove in the periphery without accidentally touching the capsule. Since the advent of Nagahara’s chopping techniques, and its multiple variants, hydrodelamination is no longer required. It is, however, still utilized as a means of inducing a soft nucleus to break it into its component parts and permit it to be aspirated easily, especially in young adults. Once the hydrodissection has been done, the nucleus is rotated utilizing a lens rotator. It should rotate freely with no hesitation. If it does not rotate, it is important that you hydrodissect once again. The next step depends on whether the surgeon wishes to either flip the lens out of the bag on its front side (supracapsular tumble) or enable the lens to stand vertically (vertical phacoemulsification), or float the entire lens out (anterior chamber phacoemulsification) (Visco-levitation) (Fig. 19.7) Mehta (1995) Kelman (1997). All three techniques are done by injecting viscoelastic under the lens capsule, at 9.00 O’clock, irrespective of whether it is the Fig. 19.7: Viscodissection to permit nucleus to right or left eye. Injecting at this site leads stand vertically the 3.00 O’clock position of the lens (temporal in the left eye, nasal in the right eye) to tip forwards. Using the same cannula which is being used to inject the viscoelastic, gently nudge the inferior pole of the lens,. A small nudge will make it stand up vertically (Lens salute, Mehta 1997.), if more is injected, the lens will flip over and can be rotated out of the bag supracapsularly (Maloney 1997). If one injects without tipping the inferior pole, it will, if the rhexis is 7.00 mm or more in size, float vertically upwards or viscolevitate (Mehta/Kelman). PHACOEMULSIFICATION TECHNIQUE (Figs 19.8 to 31) There are two methods which I use: the first is the tangential phaco chopping technique—a method which was popularized in 1996 (Mehta), and the second which I prefer is the vertical nuclear ‘hubbing’ phacoemulsification. In 1996 I developed the tangential chopping technique whereby the chop rather than going vertically through the substance of the lens, would go obliquely. One had merely to tip an edge of the nucleus out, impact the nucleus in the middle with a phaco tip and using a sharp-edged but blunt-tipped chopper obliquely the

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Fig. 19.8: Impaction of phaco tip into nucleus

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Fig. 19.9: Chopping proceeds

Fig. 19.10: Lens chopped vertically

Fig. 19.11: Fragment turned and repositioned for chopping

Fig. 19.12: Fragment chopped

Fig. 19.13: Fragment impacted and chopped

lens is plot from the periphery to the center. The advantage was that rather than trying to split the lens vertically literally “shards” of the lens were removed. The lens was rotated and then chopped again, once again obliquely. Ultimately only the thin central shard was remaining which could be flipped out and phacoed. It proved very effective especially in hard cataracts. The big advantage was that the capsule was never at risk.

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Fig. 19.14: Pulse phaco to remove final fragment

Fig. 19.15: Irrigation aspiration to remove cortical remnants

Fig. 19.16: Insertion of foldable lens in eye

Fig. 19.17: Tripod (IOLTECH) lens in its own cataset case

Fig. 19.18: Tripod (IOLTEC) being gripped over the ridge in case

Fig. 19.19: Lens being gripped with one tripod followed and two flexed

In 1998, I conceived of the concept of vertical phacoemulsification whereby the nucleus was tilted vertically. Considering that the maximum density of the nucleus is on the middle, common sense dictated that if one could remove the hard central core, one would literally convert the entire nucleus into a simple doughnut. The

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Fig. 19.20: Lens being inserted with leading tripod under capsular edge

Fig. 19.22: Tripod lens well positioned in bag

Fig. 19.24: Soft plastic tip being removed from case

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Fig. 19.21: Lens released allowing both proximal loops to slip in bag automatically

Fig. 19.23: Insertion of SI 40 Allergan lens with Allergan un-folder injector

Fig. 19.25: SI40 silicone lens being positioned in folder

peripheral ring composed off much softer nucleus and epinucleus would come out easily. I, therefore, designed the system of “hubbing” phacoemulsification, where the nucleus could be ‘hubbed’ or removed by coring out the middle of the lens.

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Fig. 19.26: Folder being closed

Fig. 19.28: Lens being injected into the eye

Fig. 19.30: Inferior loop trailing being inserted into bag

Fig. 19.27: Folder placed in Allergan “unfolder ” injector

Fig. 19.29: Lens completely unfolded— superior loop swinging in bag

Fig. 19.31: Lens in good position

Technique of Vertical “Hubbing” Phacoemulsification It is a very simple technique. So simple in fact that when I demonstrate it to visitors in my theater, the first comment usually is…”looks easy… why has no one thought of it?“.

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The technique involves a 6.00 mm rhexis, following a full hydrodissection placing the nucleus vertical viscodissection at the 9.00 O’clock position with the nucleus at 3.00 O’clock position standing out of the capsule bag (Lens salute). The steps of the surgery are as under: Nuclear stabilization Viscoelastic is injected from the side port incision. This manages to stabilize the nucleus and prevent it flopping back. From the side port, enter with the blunt-tipped, but sharp-sided chopper and support the nucleus. Coring the nucleus The next step is to core out the center of the lens. In this technique termed “hubbing”, I like to use the Kelman bent 0.9 dia phaco tip as it penetrate easily in the nuclear matter. The phaco settings are now altered to 70% phaco power, vacuum is reduced to the minimum. Thus, when energized, the phaco tip can penetrate, and move out of the nucleus without displacing it since no suction is involved. Supporting the nucleus from the left with the phaco chopper held flat against the nuclear surface to stabilize it, the phaco tip is placed squarely in the middle of the lens and literally allowed to penetrate virtually all the way through. The first core, made in the middle of the nucleus is called the primary core. Subsequently make three, one secondary core just above, and two, one at each side of the primary core. The next step is to rotate the nucleus by 90° and make the final core. In any lens up to grade 4 in density, a total of five cores (one central primary and four secondary cores) will literally, eliminate the hard central nuclear matter. If it is harder cataract, another set of four cores (termed tertiary cores)are placed a little peripherally and in between the previous four secondary cores. Snapping the periphery The lens is now converted into a doughnut. To aspirate the final rim, it needs to be snapped. The chopper, which till the present was only supporting the nucleus for the coring is now allowed to slip in-between the cored nucleus. Using a phaco in the right hand, the ring is split open using the sharp inner curve of the chopper. After snapping the ring, it is slightly widened. Pulse aspiration of the ring The open end of the doughnut ring is allowed to impact onto the phaco tip. The settings now change, ultrasound power is kept at 20 to 30% depending in the density of the lens, set pulse at 8 pulses per second. Vacuum is set at 400 mm Hg, Flow rate at 18 ml/min, energizing the tip will lead the entire rim of the lens to rotate (carrousel) till it is fully removed. An average phacoemulsification, from beginning to end, done with no haste, in a medium dense grade 4 cataract, with this technique can be completed easily in 6 minutes. Indications Though it is an exceptional technique and can be used in virtually any type of density of nucleus, it, however, does require a little care. It is difficult to tumble the lens through a rhexis smaller than 6.00 mm in size. It is possible to enlarge

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the rhexis using the split rotation technique described elsewhere. Since the quantum of ultrasound energy liberated in the anterior chamber is very low, it can be used safely in Fuch’s dystrophy, patients with a low endothelial cell count, or prior keratoplasty, where the regular options do not apply. The important question, often asked is whether doing a regular phacoemulsification as compared to a vertical phacoemulsification shows any disparity in endothelial cell loss. It is often thought that since, in coring U/S energy is used more, the endothelial cells may be affected. But in fact the extra energy is masked off the cells by the fact that a phaco needle buried in the substance of a lens does not radiate any energy out. A Topcon endothelial specular non-contact microscope coupled with its own special “ImageNet” software, showed no cell loss of any significance in a series of 125 consecutive cases. Though, in theory, endothelial cell changes must occur in any surgery, in practice there is hardly a +/- 3.00% variation change in the endothelial cell count. Perhaps the greatest application of this technique is that it is an exceptional transition technique for teaching residents, fellows and young pledging surgeons the art of phacoemulsification without inducing any complications. It is easy to do, minimizes the risks of capsular damage, removes the chances of inadvertent iris contact, and enables even a hard cataract be done with safety in a short period of time. It is thus the technique of choice in eye camps where, I am sure, it will supplant the regular technique in time. FURTHER READING 1. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-166,1986. 2. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in paediatric cataracts. All India Ophthl Soc Proc 207-210,1995. 3. Mehta KR: An advanced but simple keratometer for control of postoperative astigmatism. All India Ophthl Soc Proc 122-123,1990. 4. Mehta KR: The new clover leaf stabiliser (CLS) for the safe and effective insertion of posterior chamber IOL over a broken capsular face. All India Ophthl Soc Proc 251-253,1995. 5. Mehta KR: Shelve and shear phacoemulsification: All India Ophthl Soc Proc (Mumbai) 1995. 6. Mehta KR: Mehta tangential chop (MTC) technique for phacoemulsification. All India Ophthl Soc Proc (Chandigarh) 1996. 7. Mehta KR: HEMA intracameral hood—corneal turbulence control in phaco. All India Ophthl Soc Proc (Chandigarh) 1996. 8. Mehta KR: Phaco-levitation—a peaceful way. All India Ophthl Soc Proc (Chandigarh) 1996. 9. Mehta KR: Lollipop phaco cleavage—a new technique for hard cataracts. All India Ophthl Soc Proc (Bangalore) 1991. 10. Mehta KR: Phaco with flexible IOL—is it a step forward. All India Ophthl Soc Proc (Bangalore) 1991. 11. Mehta KR: The prephaco split technique using the contrasplit forceps–a new technique. All India Ophthl Soc Proc 1998. 12. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification–a simple technique. APIIA Conference, 1997. 13. Mehta KR: Astigmatic control using the new curved—laminating keratotomy technique. APIIA Conference 1997. 14. Mehta KR: The tripod posterior chamber foldable acrylic lens. Proc of SAARC Conference, Nepal, 1994. 15. Mehta KR: Phacoemulsification, the “roller-flip” way for suprahard cataracts—it works great. Proc of SAARC Conference, Nepal, 1994.

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16. Mehta KR: Intralenticular phacoemulsification—a new technique. Proc of SAARC Conference, Nepal, 1994. 17. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 18. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 19. Mehta KR: Effective endothelial cell protection during phacoemulsification with HEMA intracameral contact lens (HICL). Proc of SAARC Conference, Nepal, 1994. 20. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

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Vijay K Dada Namrata Sharma Tanuj Dada

Innovative Nucleotomy Techniques

20

INTRODUCTION Phacoemulsification is now the most preferred modality for cataract extraction according to the latest ASCRS survey.1 The various nucleotomy techniques are generated to avoid complications and to ensure safe phacoemulsification procedure. We herein, describe the following nucleotomy techniques. • Modified phacoemulsification in situ, for weak zonular apparatus. • Petalloid phacoemulsification, for hard cataracts • Sinus fracture and intranuclear nucleotomy, for semihard cataracts, and • Slit nucleotomy technique for soft cataracts. MODIFIED

PHACOEMULSIFICATION

IN

SITU

A modified methodology of in situ phacoemulsification is described which imparts minimal stress on the zonular apparatus. This is especially relevant in cases of zonular weakness where undue stretch may cause partial or total zonular dialysis during rotation. The phaco procedure is begun by inserting the phaco tip into the chamber prior to emulsification. Central sculpting a groove approximately 2½ to 3 phaco tips wide with specific attention to down sculpting, approximately 90% of nucleus depth, is done in order to consume part of the posterior plate or the backbone of the nucleus (Fig. 20.1A), thus, the central hard nucleus, epinucleus and cortex within the confines of the capsular bag. For this debulking procedure, the phaco power is initially kept at 50% and increased further as per the hardness of the nucleus. The aspiration flow of fluid is 20 cc/min and vacuum is 11 mm Hg.

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Fig. 20.1A: Central debulking, sculpting to 90% depth

Fig. 20.1B: Horizontal fracture along 3 and 9’O clock meridian

A deep groove facilitates instruments to be in place for a subsequent fracture and increases the working space. During this part of phaco it is imperative not to rock or move the nucleus so as to keep the zonules and anterior capsule intact. Following an adequate debulking, the second instrument (chopper) is inserted through the side port and a horizontal fracture is created by karate fracture at 6 O’ clock to divide the lower half of the nucleus into 2 quadrants. Right

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Fig. 20.1C: Vertical fracture of the inferior hemisection

Fig. 20.1D: Pie-shaped nucleus is phacoemulsified after stabilization with the second instrument

hand fixes the nucleus on the right side of the center, left hand does vertical fracture at the center by downwards movement of the blunt chopper along 3 and 9 O’clock meridian (Fig. 20.1B). Fracture into distal and proximal half is done after complete removal of the foot from foot pedal, i.e. no function. The phaco tip is then used to engage the inferior hemisection and 2 pie-shaped “pizza

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pieces” are fractured using the second instrument to stabilize the nucleus (Fig. 20.1C). The tip of the quadrant or “pie” is engaged into the phaco tip and pulled forwards into the center pupillary zone for safe emulsification (Figs 20.1D and E). The second instrument/chopper/manipulator may be used to tilt the central apical portion up in order to facilitate grasping by the phaco tip just as in other nuclear cracking techniques. If necessary (i.e. in cases of large and dense endonuclei) individual fragments may be cleaved further, resulting in small manageable

Fig. 20.1E: Superior hemisection left for phacoemulsification

Fig. 20.1F: Deep groove facilitated at superior hemisection

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Fig. 20.1G: Vertical fracture facilitated at superior hemisection (no nucleus rotation)

Fig. 20.1H: The level of the phaco tip is turned down to emulsify the pie-shaped nuclear fragment

fragments, small enough to be aspirated. A crater is then created in the proximal half within the confines of the capsulorrhexis in situ, without rotation of the nucleus (Fig. 20.1F). The phaco tip is directed slightly downwards just as one does during sculpting. The groove is used to fracture the upper hemisected nucleus

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into 2 quadrants (Fig. 20.1G). The bevel of the phaco tip is turned down to pick up each quadrant separately which is emulsified in situ (Fig. 20.1H). This modified methodology of central debulking and in situ phacoemulsifcation is particularly suitable in cases where degree of stress imparted to the zonular apparatus has to be minimized. It is especially relevant in cases of anticipated weak zonular apparatus, like pseudoexfoliation, uveitis, hypermature or traumatic cataracts and glaucoma. This technique further ensures minimal lens rotation and eliminates the need to sculpt in the periphery. A remarkable index of safety is entailed as each fragment is emulsified in the central safety zone in a stable environment with the phaco tip. Moreover, as no sharp instruments approach the posterior capsule, this technique is safer than the conventional chopping technique. PETALLOID

PHACOEMULSIFICATION

Transitional phaco surgeons may hesitate to deeply chop the central core of hard cataracts which resists complete division even in expert hands due to elasticity and tenacity of the posterior nuclear plate. If the instruments are placed too anteriorly in the trench, the bottom of the bridge is not split, because the inappropriate placement of instruments creates a torque in the area rather than a splitting force.2 On the other hand, an inappropriate deeper fracture may inadvertently rupture the posterior capsule. We herein, describe a useful technique for phaco surgeons who are still in the learning curve for performing phacofracture of hard nuclei. Technique Debulking of the central hard nucleus is facilitated by sculpting a crater (75% depth) with the phaco tip (Figs 20.2A and B). The phaco parametres are: power— 70% and vacuum—10 to 12 mm Hg. This removes the hardest core tissue from within the middle of the hard cataract and provides enough room for the working of the instruments and subsequent manipulation of the nuclear fragments. The 2nd instrument (chopper) is introduced via the side port and Nagahara chopping3 is facilitated within the confines of the capsulorrhexis to separate out a petal shaped nuclear fragment still attached to the unchopped intact central disc (Fig. 20.2C). The nucleus is then rotated by 2 to 3 clock hours and another petalshaped fragment is chopped. Each ‘petal’ constitutes predominantly the nuclear rim, the base of which is formed by the central disc, giving it a petalloid configuration. The same technique of rotation, chopping and rotation is performed to form 6 to 12 such “petals” depending on the hardness of the nucleus (Fig. 20.2D). The vacuum is raised 100 to 110 mm Hg during nuclear emulsification. Each petal may be emulsified in the central capsular bag separately or all may be left in place until all “petals” have been formed. The advantage of waiting until all “petals” have been formed is the maintenance of maximal capsular distention which keeps the capsular bag stretched and helps to avoid inadvertent posterior capsular tear. However, the advantage of removing each fragment separately is

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to allow more space for easy chopping of the other segments of the remaining rim. Nevertheless, caution is mandatory while doing the latter since, as more segments are removed, less lens material is available to expand the capsule and the lax capsule has a greater tendency to be aspirated into the phaco tip especially if high aspiration rates are used. Following consumption of the nuclear rim (Fig. 20.2E), the central mobile disc of the nucleus (Fig. 20.2F) is emulsified. Twenty eyes underwent petalloid phacoemulsification with foldable silicone intraocular lens implantation (SI30NB:Allergan ) with no untoward intraoperative complications. The mean phaco time was 1.02 ± 0.06 minutes and the mean percentage endothelial cell loss was 4.2 ± 0.8% at the end of 3 months follow-up. Postoperatively, all eyes achieved a visual acuity of 20/20 at the end of first week.

Figs 20.2A to F: (a and b) Central debulking upto 75% depth, (c) Karate chop at the paracenter to create the edge of a petal, (d) Chopping, rotation and chopping create the petalloid configuration, (e) The central disk and the base of the petal remains following emulsification of the petals, and (f) central disk and the base of the petal are emulsified in the end

This technique is based on the anatomic relationship between the lens fibers and the lenticular sutures. During embryologic development lens fibers elongate and join forming 2 sutures, one anteriorly and one posteriorly.4,5 With time, as more fibers are added these sutures branch off into increasingly complex patterns. The radially oriented fibers create potential cleavage planes that are amenable to separation.5 The lens epithelial cells lay down concentric layers of nuclear tissue which become dense centrally and less dense peripherally. These concentric layers resemble the lamellar organisation of a tree trunk. Thus the peripheral area of a hard cataract offers less resistance and a more predictable shearing stress as compared to the center which is much more dense.

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This modified method of “petalloid” phacoemulsification is particularly suitable and comfortable for transitional phaco surgeons who are as yet hesitant to completely chop the dense central core of hard nuclei. An experienced surgeon may be able to determine and gauge the depth of the central crater and the density of tenacious and elastic fibers of the posterior plate. However, this may not be true for the beginners. For learning phaco surgeons chopping in the center of a hard nucleus is difficult, as the hardness of the nucleus precludes the depth at which the fracture has to be facilitated. On the other hand, chopping the relatively softer “paracenter” may allow a better perception of depth. The fracture which is radial is more physiological with the arrangement of the lens fibers as compared to the one which is horizontal. In an untoward situation, the traditional horizontal fracture may cause an unexpected and unequal break in the nucleus so that the phaco probe directly impinges on the posterior capsule. The process of partial central debulking, peripheral chopping and emulsification and then central disc emulsification offers a more graduated effect and is thus more predictable. A greater predictability is attributed to impaling from less hard periphery towards a more hard central core. Thus this procedure works on progressive harder gradient by going from periphery towards the paracenter. The small residual nucleus core is phacoemulsified separately with ease due to its small size and larger room for manipulation and movement. We recommend this procedure as an alternative to technique of performing phacofracture of a hard nucleus during phacoemulsification. SINUS

FRACTURE

AND

INTRANUCLEAR

NUCLEOTOMY

The technique of sinus fracture and intranuclear nucleotomy facilitates and accomplishes a successful phacoemulsification in dense or hard nuclei. Technique Using a 30o phaco tip a central crater is sculpted approximately 2.5 to 3 phaco tips wide and upto 90% of the nuclear depth. The central hard nucleus is debulked, leaving a peripheral rim of nucleus, epinucleus and cortex within the confines of the capsular bag. A deep groove allows instruments to be in place for a subsequent horizontal fracture of the nucleus into two halves. The phaco probe with bevel upwards is then inserted into the center of the inferior hemisection to create a sinus (Fig. 20.3A). The lateral wall of the sinus is widened to accommodate the phaco tip and the chopper (Fig. 20.3B). A mechanical force is then applied along the lateral wall of the sinus with these two instruments (Fig. 20.3C). Thus the inferior hemisection is divided into two quadrants (Fig. 20.3D). The individual fragments may then be cleaved further in a similar manner and aspirated out. The superior nuclear hemisection is dealt with, in a similar way. In intranuclear nucleotomy, 4 such sinuses are made (Figs 20.3E and F) each at 90° to each other. This is followed by the breaking of the 4 sinuses so that 4 quadrants are generated which are then subsequently emulsified.

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Figs 20.3A to D: (a) Phacoprobe is inserted in the hemisection, (b) Chopper is inserted in the hemisection from the site port, (c and d) lateral force is applied to split the hemisection into two quadrants

Figs 20.3E and F: (e) Four sinuses are created for intranuclear nucleotomy, and (f) four sinuses are broken to create four quadrants

Sinus fracture was performed in 50 cases with grade IV nuclear density by a single surgeon (VKD). No intraoperative or postoperative complications were encountered. Successful phacoemulsification was achieved in all eyes. Visual acuity of > 20/40 was obtained in all cases at the end of 1 week. The mean phaco time was 1.09 + 0.6 minutes and mean endothelial cell loss at the end of 3 months was 4.6% + 0.7%. This technique is especially advantageous as the phaco tip is buried deep into the inferior hemisection and thus it reduces the amount of ultrasound energy

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directed towards the corneal endothelium and the posterior capsule. The turbulence within the eye is decreased which cuts down the production of free radicals generated by the ultrasonic energy hitting the endothelium. The procedure is especially effective on grade IV hard nuclei which might be considered difficult to perform using other phaco techniques. Since no sharp objects approach the posterior capsule, this technique is safer than conventional chopping procedures. The chopper is not inserted underneath the capsule or the iris and therefore the chopping is accomplished far away from the edge of the capsulorrhexis and the endothelium, within the pupil. The large nuclear fragments do not shift into the anterior chamber, thereby decreasing the possibility of endothelium damage. This technique offers higher safety against damaging the capsule and should be adopted as a routine in phacoemulsification of hard and brunescent nuclei. SLIT

NUCLEOTOMY

Phacoemulsification in soft cataracts is as challenging as phacoemulsification in hard cataracts as the capsular bag is relatively loose and phaco probe may cut through the nuclear material without being emulsified. In soft cataracts, a vertical narrow and a deep slit facilitates fracture more easily as there is no cheese wiring (Figs 20.4A and B). Further enough support occurs to ensure adequate purchase on the walls which ensures a cleaner fractures. We do not recommend a wide crater in soft cataracts as enough nuclear material is not present to ensure an adequate fracture.

Figs 20.4A and B: (A) Slit is created with the phacoprobe, and (B) slit is split to create two hemisections

REFERENCES 1. Leaming DV: Practice styles and preferences of ASCRS members—1996 survey. J Cataract Refract Surg 23: 527-35, 1997. 2. Seibel BS: Phacodynamics: Mastering the Tools and Techniques of Phacoemulsification. Slack Inc: Thorofare, 1993. 3. Gimbel HV: Nuclear phacoemulsification. In Steinert (Ed): Cataract Surgery : Technique, Complications and Management. WB Saunders: Philadelphia; 148-161, 1995. 4. Bron A, Smith R et al : Changes in light scatter and width measurement from the human lens cortex with age. Eye 6:55-59, 1992. 5. Duke Elder S: Anatomy of the visual system. In System of Ophthalmology. Vol.II, CV Mosby: St. Louis, 320-23, 1961.

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Rasik B Vajpayee Tanuj Dada Vishal Gupta

21

Phacoemulsification in White Cataracts

INTRODUCTION The white cataract, for most surgeons, is perceived as a major challenge to their skill. In ophthalmic practice in the developed world the incidence of these cataracts is low, whereas in the developing countries they represent a significant number of patients seen and operated upon. These eyes are often looked upon with foreboding because of the potential pitfalls envisaged in their surgery. In this chapter, alogical framework is provided to allow many of the problems to be overcome. REASONS

FOR

CATARACTS

TURNING

WHITE

Cataracts are caused in many cases by separation of lamellae within the lens and imbibition of water into these spaces. As this process continues the lens starts to swell and once this occurs it is described as intumescent, these cataracts may be immature or mature. However, the common feature is that the cortex has swollen so that it no longer transmits light and has a shiny hyaline appearance. The nucleus is frequently chalky and small but may also, particularly in older patients, contain a large brunescent nucleus. A later stage of development is the hypermature lens where fluid has begun to leak from the lens and the capsule is wrinkled. MORPHOLOGICAL

CLASSIFICATION

Let us first consider the main types of lenses that are found with white cataracts. Type A (Fig. 21.1)

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Fig. 21.1: Type A white cataract

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Fig. 21.2: Type B white cataract

Posterior subcapsular cataracts that have been allowed to proceed to maturity These are generally found in younger patients and in the author’s practice in patients of Asian origin. These cataracts have small nuclei and considerable amounts of liquefied lens material. Type B (Fig. 21.2) Hypermature cataracts in older patients often uniocular in non-dominant eyes They tend to have large highly sclerotic nuclei and a thin overlying layer—white cortical matter. The nucleus may have become mobile within the capsular bag as in morgagnian cataracts. Type C (Fig. 21.3) Shrunken fibrotic lenses as seen in complicated uveitic cataracts and eyes that have had a penetrating injury In the latter, there is often little by way of nucleus or cortex between the leaves of the capsule, it may have liquefied and leaked out through a small capsular perforation. The uveitic lenses are often calcified and may need to be removed manually (Fig. 21.4) in a piecemeal manner or

Fig. 21.3: Type C white cataract

Fig.21.4: Manual removal of lens

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PHACOEMULSIFICATION with a vitreous cutter. Often the implant if used will require scleral fixation as no adequate capsular remnants will exist (Fig. 21.5). Type D

Fig. 21.5: Close-up view of uveitic cataract

MANAGEMENT

OF

WHITE

Infantile cataracts such as those caused by maternal rubella very often present as white cataracts. These are normally dealt with by aspiration or lensectomy and so really fall outside the scope of this chapter. CATARACTS

Preoperative Considerations Ophthalmic History Take a careful history to ascertain the following • If there have been any obvious predisposing factors such as trauma or infla– mmatory disease. • The length of the time that vision has been poor and is the problem uniocular. This is important because a long-standing uniocular cataract may well hide significant posterior segment disease of which the patient is unaware. • Precataract vision should be ascertained if possible, there is no point removing a white cataract from an amblyopic eye except for cosmetic reasons. Examination • When checking visual acuity in patients with dense cataracts of this type it is important to carry out a test of light projection. This should be done in an otherwise darkened room using a strong point source of light in each quadrant of vision. Failure to point accurately to the light in any quadrant may indicate significant posterior segment disease. • The anterior segment examination may show evidence of previous penetrating injury. There may be synechiae or pigment on the anterior lens surface indicating inflammatory disease or anterior chamber activity. • Always check the intraocular pressure (IOP), if it is raised there may be unsuspected uniocular glaucoma or because the cataract is swollen and surgery is going to be necessary urgently. If it is low the eye may be becoming phthisical posterior segment problems such as unrepaired retinal detachment may cause this. • Check the cataract itself. Is it swollen and has it shallowed the anterior chamber. Is the nucleus visible at all through the cortex and is it brunescent or morgagnian. Has the capsule become wrinkled indicating leakage of fluid from the lens. • Check the fellow eye. It is most unusual that the other eye, even if it does contain a cataract, will be so bad that no fundal view is precluded. A knowledge that there is age-related maculopathy present is useful in advising the patient about the possible prognosis for vision.

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Tests

It is essential to carry out an ultrasonic B-scan in patients where the posterior pole is obscured by cataract. This is done to exclude such things as ocular tumors like malignant melanoma of the choroid or retinal detachments. Problems of this type are usually seen where the history has been long-standing and the cataract is uniocular. Surgical Considerations The reasons why these cataracts represent so much of a challenge to the surgeon are three-fold: (i) the lack of any red reflex, (ii) the effect on the ocular tissues of the advanced nature of the disease process, and (iii) the nuclei in these eyes are often small and mobile, whilst some are brittle others can be very hard. Although the capsulorrhexis is certainly the most likely part of the operation to cause difficulty, even if that is successfully achieved, the rest of the ocular tissues in the anterior chamber are more friable than usual and the nucleus may be more difficult to control. Capsulotomy Owing to the difficulties of visualizing the capsule, capsulorrhexis, if the chosen method, presents the most taxing part of the operation in most of these eyes. However as capsulorrhexis confers distinct advantages for the rest of the operation it should ideally be the method used. General Tips to Help Improve Visibility during Capsulorrhexis • Operate from the temporal aspect, the visibility and overall surgical access is surprisingly improved. • Tilt the microscope eyepieces towards you to create oblique illumination, like the sun in winter this creates shadows and throws the capsule into relief. The torn edge of the capsule also has an edge reflection to enhance its location against the white cortex. Some microscopes have an oblique non-coaxial light which is even better for this. A fiberoptic light pipe introduced into the anterior chamber can enhance the view of the tearing capsule very considerably (Fig. 21.6). The room and microscope lights need to be extinguished to get the best effect from this maneuver. • Use very high magnification during the capsulotomy and focus accurately at the plane of the anterior cap. • Overfill the anterior chamber with viscoelastic, a cohesive material like Viscoat (Alcon) or high concentration sodium hyaluronate such as Healon GV (Pharmacia Upjohn) are best for this as they are less likely to escape from the eye at awkward moments. This will flatten the anterior capsule and thus lessen the tendency for the capsule to tear to the periphery. Also the full anterior chamber (AC) will contain the liquid lens matter escaping and minimizes loss of visibility.

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Fig. 21.6: Using the light pipe for the capsulotomy

Fig. 21.7: Starting the rhexis

• Attempts have been made in the past to stain the anterior capsule but until recently unsuccessfully. Indocyanin green has now been used to achieve this and aid capsular visibility for capsulorrhexis. • Take your time. Reassess frequently where the tear is and be prepared to top up viscoelastic or refocus or move the light as required to get the best view. Specific Tips • Begin the capsulorrhexis in the center of the capsule with a small tear to allow lens milk to escape (Fig. 21.7). If there is extensive milky fluid obscuring the view of the capsule, remove the cystitome and use the I/A handpieces to aspirate this (Fig. 21.8), also go under the capsule for anterior soft lens material. This lessens the highly reflective nature of the anterior cortex and improves the visibility of the capsule. Using high magnification will allow the surgeon to observe the subtle difference between cortex covered by capsule and that, which is not (Fig. 21.9). • Grasp the torn edge of the capsule firmly, attempt only a small 4.5 mm rhexis. These capsules are often friable and easily extend. A small capsulotomy can always be enlarged later if required. • If the edge of the capsule is lost STOP. Reinflate the AC with viscoelastic, very often this will demonstrate where the capsulotomy has reached and control can be regained. If the edge is still not seen try changing the angle of the microscope to allow the light to play differently on the capsule, increase the magnification further and refocus on where you think it is. • If the rhexis edge is still illusive, consider beginning it again in the opposite direction. This can usually be achieved using the cystitome; begin on the capsule and cut towards the center (Fig. 21.10). This produces a flap which when lifted by viscoelastic can be grasped in the forceps and the two halves of the rhexis may thus be joined.

PHACOEMULSIFICATION

Fig. 21.8: Using the bimanual I/A to clear lens fluid

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Fig. 21.9: Slight color difference apparent with oblique illumination

By using these few simple maneuvers in an unhurried manner, a satisfactory rhexis can generally be achieved. If the rhexis is known to be compromised and cannot be retrieved either revert to a canopener capsulotomy and then perform iris plane phaco as described by Maloney and others or use cautious nucleofractis. In both instances remember that these capsules, both anterior and posterior, are easily damaged. Fig. 21.10: Restarting the rhexis

Radiofrequency Endodiathermy for Capsulotomy An alternative method for achieving a capsular opening which does not require such accurate visualization of the capsule is to use an endodiathermy. The tip of the device is moved slowly around the anterior capsule to create a circular opening. This is achieved due to thermal effect and anneals the capsular edge. Although as a number of studies have shown this edge is not as strong as a capsulorrhexis, it is at least better than a torn or incomplete rhexis when IOL stability within the capsular bag is considered. Also if the device is available it removes much of the anxiety associated with this type of eye. The major disadvantage is the cost if white Fig. 21.11: High frequency radiodiathermy for cataracts are not a common part of a the capsulotomy surgeons clinical practice.

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Hydrodissection Both in the softer more liquid white cataracts and those with hard nuclei, hydrodissection is usually easily achieved as the cortex is rarely very adherent. Do not use great pressure on the syringe or soft lens matter under the nucleus will be washed out of the eye and thus will not be able to provide any protection for the posterior capsule during nucleus removal. The loose cortex in these eyes means these nuclei tend to be mobilized with minimal manipulation. Tips for Nuclear Removal Type A Cataracts In type A cataracts the nuclei are small and chalky though not usually very hard. Their mobility may make removal difficult because of the tendency to move away from the phaco tip. • Use the manipulator to stabilize the nucleus (Fig. 21.12). • Use higher phaco power, i.e. 70 to 80 percent to accelerate the tip into the nucleus in conjunction with higher vacuum to hold the tip and thus control it. • Whether cracking or chopping (Fig. 21.13) be aware that the fragments of these nuclei can damage either capsule or endothelium because of their mobility. A layer of Viscoat above and below the nucleus prior to nuclear removal can be helpful in this regard. If successful rhexis has been achieved these nuclei do not normally tax the surgeon’s skill. Type B Cataracts Type B cataracts have nuclei that are often brunescent. Remember the posterior capsule is not protected by a good layer of epinucleus and what is present is often washed out by the irrigating fluid. As above remember that the capsule and endothelium are particularly at risk. Also the zonules are often less strong than normal. Consider: • The use of viscoelastic as above. The capsule protector suggested by Dr Michael

Fig. 21.12: The manipulator is used to stabilize the nucleus

Fig. 21.13: Cracking the nucleus

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Colvard if available would be useful to slip under the nucleus to protect the posterior capsule. • Whatever technique is used to break up the nucleus that must be employed with great caution. Chopping may be particularly difficult and hazardous if the rhexis edge is not clearly seen. The chopper can be passed over the top of the rhexis and when chopping is attempted the zonule disinserted. If after Fig. 21.14: High vacuum low phaco power nucleofractis the quadrants are too big for easy removal, they can be chopped individually in the center of the rhexis. • Use a modern phaco machine with high vacuum capability and advanced fluidics to control the nuclear fragments (Fig. 21.14). With these very hard nuclei, it is particularly important to avoid anterior chamber collapse as both endothelium and posterior capsule are at risk. However using high vacuum to minimize ultrasound energy used with a machine that does not have some sort of surge control mechanism of the fluidics is much more likely to lead to anterior chamber instability. Type C Cataracts This last group of cataracts is rather more varied in etiology, i.e. from uveitis to trauma but they generally present a similar picture. The capsule is shrunken, often very leathery and frequently with calcified plaques on either surface. The lens matter may have leaked out to a large extent so that anterior and posterior capsules are fused. If this last is not recognized attempting to do any capsulotomy may result in rupturing the anterior hyaloid. Lensectomy, using a guillotine suction cutter is a good method, phacoemulsification is generally impossible. Sometimes the lenses are so tough that they cannot be cut up and need to be removed intracapsularly as a whole (Fig. 21.5). Tips for Cortical Aspiration • As already stated the cortex in these eyes tends to be very liquid, most of it will therefore wash out. • Occasionally, however, a tough shell of epinucleus may be left behind after the nucleus has been removed. These can prove rather tiresome because the edge is not easy to aspirate. Viscoelastic injected under this plate to lift it and using the phaco tip rather than the I/A tip with its wider bore often helps. • Even with a complete rhexis prior to nuclear removal it is not unusual to find that whatever method has been used to get rid of the nucleus a rhexis break has resulted. It is important to recognize this and to make sure any edges to the capsular tear are not aspirated by mistake during I/A. Using bimanual I/A allows for a deeper chamber and better control of the capsular edge.

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• It is not unusual to find quite dense plaques on the posterior capsule in some of these eyes. Some will polish sufficiently with a Kratz scratcher or similar device to avoid the need for further action until postoperative vision has been assessed. Others are so dense that the solution of choice is to perform a posterior capsulorrhexis. Sometimes these plaques actually are part of the posterior capsule and when they abraded will come away leaving the hyaloid face exposed. Tips for Lens Implantation If the eye is healthy and all is as it should be after cortical aspiration any lens of the surgeon’s choice can be implanted. However if there is a history of preoperative trauma and damaged zonules, implant an endocapsular ring prior to IOL insertion to stabilize the capsular bag. If the cataract is uveitic in origin the use of AcrySof (Alcon) is recommended if a folding lens is desired. In the authors’ experience this lens performs at least as well heparin surface, modified Fig. 21.15: Well-centered AcrySof with haptics at 90 degrees from rhexis break PMMA lenses (Pharmacia Upjohn) in such cases. If as is suggested above a rhexis break has occurred, great care must be exercised in choice of IOL and site of implantation. • Plate haptic lenses are not recommended as they may during unfolding extend the break. Even a 3-piece silicone IOL as it unfolds may do the same, due to the explosive nature of the release from the implanting device. However the new unfolder (Allergan) appears to overcome many of these difficulties though the authors would still recommend that the SI40 IOL with PMMA haptics is used. • A lens which unfolds slowly and which is made from a material that causes minimal capsular contraction such as the AcrySof MA60 (Alcon) is ideal (Fig. 21.15). The lens is positioned with haptics at right angles to the break in the rhexis. • If there are doubts about the status of any rhexis rim break, implant the IOL into the ciliary sulcus any IOL of sufficient length (greater than 12.5 mm) will suffice. The lens optic can then be pushed into the bag to give best stability. Postoperatively The majority of these patients have a normal postoperative course, they are placed on whatever the surgeon usually prescribes as medication. These eyes are probably more likely to exhibit corneal disturbance on the first postoperative day as greater intraocular manipulation than usual has been necessary.

Inderjit Singh

Phacoemulsification in Difficult Cases

22

INTRODUCTION Phacoemulsification cataract extraction has come a long way since the late 60s. There has been a considerable improvement in technique and in the equipment we use. Advances in software programs that allow the equipment to respond more intelligently and more precisely have also made the procedure safer. Phacoemulsification cataract extraction in routine cases can be difficult enough because conditions can change very rapidly which the surgeon has to consciously try to control. The technique becomes even more difficult to do in some situations which would be considered as difficult cases or challenges that the surgeon will meet at times. It is very important to have mastered a very structured and precise technique to be able to successfully operate on these challenging cases with minimal complications. The routine phacoemulsification technique a surgeon uses must be adaptable enough to use in these challenging cases without any major change. General Considerations The incisions used in these challenging situations can either be a clear corneal self-sealing wound or a scleral tunnel self-sealing wound. A two-ended technique is advocated for the phacoemulsification. In spite of a number of new techniques for the phacoemulsification itself, the technique that is most predictable, precise and repeatable is some form of nuclear divide and conquer. It is important to minimize the excursion of the phaco tip in these cases and of all the various techniques, the split and lift technique is probably the most useful (Fig. 22.1). This technique allows the phaco tip to work within a small

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Fig. 22.1: A phacoemulsification technique suitable for “difficult” cases

Fig. 22.2: Safe zone phacoemulsification. Note position of safe zone

safe zone area (Fig. 22.2) and is particularly useful in small pupil phacoemulsification. In summary, the split and lift technique has several distinct advantages. • It is a bimanual method which gives more control of the nuclear pieces. • The phacoemulsification is done in the safe zone. • Phacoemulsification is done within the capsular bag. • It is very useful for a hard nucleus. • It is very useful in situations where the pupil is extremely small. The essence of the technique Fig. 22.3: Split and lift phaco technique. Note quadrant here is to move the nucleus into control and safe zone phaco the safe zone and split the nucleus into four quadrants. Each quadrant is then lifted from its apex into the phacoemulsification tip. The second instrument is used for quadrant control and if need be for a phaco chop to further divide the quadrant (Fig. 22.3).

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In all the situations the smaller the phaco tip the more control there is within the eye and it also affords much better visualization within the eye of all the tissues. It is strongly recommended in these situations to use a microtip whether it is straight or curved. The microtip has a diameter of 0.9 mm compared to the larger tips of 1.1 mm. The port size is decreased by 48% and presents a larger metal surface. This improves efficiency in cutting by increased cavitation. The smaller port also decreases surge and minimizes collapses of the anterior chamber (Fig. 22.4).

Fig. 22.4: Curved micro tip for phacoemulsification. Tip is 0.9 mm diameter. Bent tip more efficient

Hydrodissection of the nuclear cortex from the capsular bag is the most underrated step in the whole procedure. Note that hydrodissection is at multiple points (Fig. 22.5A). Both the cortical layer and nucleus is separated from the capsular bag, so that both the perinuclear cortex and nucleus are easily rotated within the bag. Easy rotation causes the least amount of zonular stress and allows the nuclear material to be brought into the phaco tip (Fig. 22.5B). Irrigation and aspiration of the cortical matter is done as per routine cases, however in most of these situations in challenging cases, the subincisional cortex is Fig. 22.5A: Multiple point hydrodissection the most difficult to remove and in these situations it is highly recommended to use some form of a curved tip, preferably a 90o tip which has been found to be most helpful (see Section on Small Pupils).

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PHACOEMULSIFICATION Difficult Cases Difficult cases would include the following commonly met challenging situations: small pupil, hard nucleus, white cataracts, pseudoexfoliation, traumatic cataract, and miscellaneous other conditions, e.g. high myopia, deep set eye, postvitrectomy eye, and patient with spinal deformities. SMALL

Fig. 22.5B: Two instrument nucleus and perinuclear cortex rotation

• • • • • •

PUPILS

Small pupils in repeated studies have been shown to be the number one cause of complications in cataract surgery. Conditions that are commonly associated with small pupils include.

Patients on chronic miotics Pseudoexfoliation with or without glaucoma therapy Small pupils associated with posterior synechiae Chronic uveitis Iris trauma Horner’s syndrome. Small pupils are usually defined as a pupil of less than 4 mm. A very small pupil would be anything between 2 mm and 3 mm (Fig. 22.6). The problems that we face with a small pupil are the esthetics of the pupil postoperatively and an attempt to maintain some pupillary function as this can be a problem with glare postoperatively. The difficulty that the phacoemulsification surgeon meets with the small pupil include. • Poor visualization which results in poor stereopsis especially posterior to the pupillary margin. • Difficult anterior capsulorrhexis. • Possible damage to the iris and iris pigment epithelium • Inadvertent zonulolysis especially in patients with pseudoexfoliation. • Tears in the anterior and posterior capsule not easily visualized during surgery. These tears can lead to the nucleus being dislodged into the vitreous. Pupils that are damaged during surgery end up being distorted and eccentric (Fig. 22.7). The main problems with distorted pupil include glare disability and problems with esthetics of the pupil.

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Fig. 22.6: Small pupil with posterior synechiae. On long-term miotics

Fig. 22.7: Iatrogenic distorted pupil. Note the exposed edge of IOL

Pupil Enlarging Surgery There have been many methods through the decades to overcome small pupils. • Keyhole iridectomy was the only method used particularly or extracapsular cataract extraction (ECCE). • Iris sphincterotomies. • Iris sutures • Modified iris tucking maneuvers. • Modified radial iridotomies.

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All the above methods have distinct disadvantages which included distorted pupil and increased bleeding from the pupillary edge during surgery and postoperatively. Theoretically there is an increased breakdown of blood-aqueous barrier causing increased inflammation and increased instances of cystoid macular edema (CME). Some of these methods also required suturing of the cut pupils and this would involve extramanipulation with added risk of retraction syndromes. These methods also do not work very well on very small pupils (Fig. 22.8).

Fig. 22.8: Sutured keyhole iridectomy. Note trauma to iris tissue

Pupilloplasty Surgery These methods involve using specially designed sutures that require multiple passes through the eye. Some of these methods also require sclerotomy. Again this method involves considerable manipulation of the iris tissue. Iris Retractors A number of iris retractors have recently come onto the market to keep the pupil enlarged. These include the following: De Juan flexible iris retractors (Grieshaber, Switzerland) Mackool iris retractors (Storz Instruments, St. Louis, Missouri) (Figs 22.9 and 10). There are a number of problems that can occur with the use of the iris retractors. The proper placement of the paracentesis for these iris retractors is very important and the pupil has to be enlarged in a gradual and controlled fashion to prevent complications. The complications can occur with the use of iris retractors and include: (i) movement of the iris too anteriorly which can result with the

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Fig. 22.9: Iris retractors for small pupil phaco

Fig. 22.10: Iris retractors. Note the number of retractors that may be required

phacoemulsification tip and instruments, (ii) the tendency to create a scaffold of iris tissue can occur if the corneal entry site hooks are too long, (iii) thermal or mechanical injuries can occur to the iris if the iris is moved too anteriorly by the retractors, (iv) tenting of the iris can occur intraoperatively if the position again is incorrect, and (v) too rapid a dilatation of the pupil may cause tearing of the pupillary sphincter.

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Fig. 22.11

Fig. 22.12

Fig. 22.13

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Figs 22.11 to 22.14: Graether pupil expander (Eagle vision, Memphis Tennessee). Note: the strap engages the pupillar y margin and keeps the pupil enlarged. The phaco tip is passed over the strap bridging the gap in the ring

Pupil Stretching Devices These are appliances that can be temporarily placed inside the eye to stretch the pupil, such as: • Hydroview Iris Protector Ring (Escalon-Trek Medical, Skillman, New Jersey). • Graether Pupil Expander (Eagle Vision, Memphis, Tennessee) (Figs 22.11 to 14). These external appliances, however, are not without their problems and possible complications. They take time to apply and because of the increased instrumentation within the eye, may cause endothelial damage. There is also significant increase in the manipulation of the iris to apply these devices successfully. Pupil Stretching Techniques Several methods have been described to stretch a pupil in order to enlarge it. Currently pupil stretching techniques are possibly the safest and most easily applied techniques for enlarging the pupil. The advantage of this technique is very small pupils with dense posterior synechiae that can easily be enlarged with this technique. This technique can also be combined with small partial sphincterotomies at the pupillary margin, especially in those small pupils that have got dense fibrotic rings. The instrumentation that is required for this technique is now fairly simple and they include push/pull iris manipulation hooks, e.g. Kuglein hooks, the Graether Iris Collar buttons (Storz Instruments, St. Louis, Missouri). In a very small fibrotic pupils where sphincterotomies are required, intraocular scissors that have blades that can be rotated around 360 degree axis can be used, e.g. Sutherland scissors (Grieshaber, Switzerland) (Figs 22.15 to 17). It is also very important to use a very retentive type of viscoelastic material which by itself can act as a tamponade to keep the pupil enlarged, e.g. Viscoat (Alcon, Fortworth, Texas). It is not necessary to stretch the pupil in several directions. In most instances stretching from 6 to 12 O’clock is more than sufficient, however where there are numerous posterior synechiae a horizontal stretching in the 3 to 9 O’clock

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Fig. 22.15: (Fine) Application of the scissors to the pupillary margin

Fig. 22.16: (Fine) Pupil after eight partial sphincterotomies

Fig. 22.17: Sutherland scissors

direction may also be required. In this situation a second paracentesis port on the opposite side is very useful (Fig. 22.18). Finally, these pupil stretching techniques can be done under topical anesthesia. It is important not to stretch the pupil all the way to the iris roots but only about two-third of the iris tissue. Anterior Capsulotomy The advantages of CCC have been described. CCC can be achieved even in small pupils. A smooth capsulorrhexis border can be made slightly larger than the small pupil by guiding the tear under the iris, at the same time observing the fold at the edge of the capsule flap. It is important that the width of the base of the triangle formed between the folded capsular flap, the pupillary margin and the apex tear can be observed carefully in order to judge how far the edge of the tear is behind the pupil. The larger the base of the triangle formed by the edge of the pupil, the farther to the periphery is the edge of the tear (Fig. 22.19).

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Fig. 22.18: Use of Kuglein hooks to enlarge small pupil

Another method of judging where the tear is occurring behind the pupil is to use a collar-stud button or a Kuglein hook to stretch the pupil in the quadrant of the advancing tear. It is important that the tear is not made excessively large and, in fact, it is prudent to make the initial capsulorrhexis smaller than one would ideally want to in a large pupil phacoemulsification. A secondary capsulorrhexis can be done if the original size of the capsulotomy was too small. This can be achieved by making a snip on the edge of one side of the capsulorrhexis and using a capsulorrhexis forceps to tear off a ribbon of the capsule, enlarging the opening of Fig. 22.19: Small pupil capsulorrhexis. the capsulorrhexis. Note circular tear is behind pupil If too small a capsulorrhexis is made it can end up postoperatively with a small fibrosed capsular opening. This can lead to subluxation of the IOL. This problem is most evident in cases of pseudoexfoliation (Fig. 22.20).

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Fig. 22.20: Excessively small CCC causing capsular phimosis and contraction

Hydrodissection Hydrodissection is possibly one of the most important steps in the entire procedure as unless the nucleus is easily rotatable the rest of the phacoemulsification becomes virtually impossible. This is particularly true in small pupil phacoemulsification where the quadrants have to be manipulated to a zone which is not only safe but easily visible. Hydrodissection would be noted to be complete once there is anterior movement of the lens-iris-diaphragm with egress of viscoelastic. There is enlargement of the pupil with this maneuver. If necessary, it is important that the rotation of the lens is checked using two hooks prior to the insertion of the phacoemulsification tip. Phacoemulsification As discussed earlier, it is important that safe, repeatable maneuver for phacoemulsification is used. It is recommended that a form of split and lift technique be used where the nucleus is divided into four quadrants and each apex of the quadrant is then lifted in the central safe zone of the pupil for phacoemulsification. Cortical Clean-up Cortical clean-up using an irrigation/aspiration cannula is undertaken. It is important that the port of the cannula be always visible to the surgeon. The cannula must be placed deep in the capsular bag to prevent any incarceration of the iris. To deepen the capsular bag it may be necessary to raise the height of the irrigating solution bottle.

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The individual quadrants of the pupils can be retracted using a second instrument and the cortex grasped with the cannula and aspirated once the cannula is brought into view within the pupillary area. The port of the cannula must be rotated superiorly before full aspiration is undertaken. The most difficult area to remove cortex, especially in small pupils, is the subincisional cortex. The problems include overhanging of the pupillary margin and the anterior capsulotomy edge. A two-instrument technique is used here whereby a 90 degree curved I/A cannula (Alcon, Fortworth, Texas) is used with retraction of the iris superiorly using a second instrument (e.g. Kuglein hook). It is important that the anterior chamber, especially the capsular bag, is kept well inflated in order the 90 degree I/A tip clears both the pupil and the anterior capsular edge before any aspiration is actually done of the subincisional cortex (Fig. 22.21).

Fig. 22.21: Varieties of I/A tips. Angled 90o tip is useful for subincisional cortical removal

A second method is to use an aspiration cannula through the side port incision and irrigating cannula placed in the cataract incision. Postoperatively the stretched pupil appears round and is cosmetically very acceptable. It is only with magnification can notches on the pupillary margin be seen. The added advantage of this technique is that most of these pupils are still functioning pupils (Fig. 22.22). Discussion There is no doubt that a small pupil presents a significant challenge to the cataract surgeon. Phacoemulsification is probably the method of choice in dealing with patients with small pupils. It is imperative that any pupil measuring less than 3 mm would require some pupil enlarging surgery. However, this can be minimized by using the pupil stretch technique or some modification of that method. This enables the phacoemulsification to be done in the bag and the IOL inserted well within the bag and minimal postoperative complications with glare and with an acceptable cosmetic result and a round pupil.

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Fig. 22.22: Post implant small pupil phaco. Note notches on pupil margin from the use of Kuglein hooks to enlarge the pupil. Pupil is still round in appearance

MATURE

HARD

NUCLEUS

In the hard nucleus the surgeon is faced with several difficulties • Poor red reflex • A thin atrophic capsule • Physical hardness of the nucleus • A large nucleus which is enclosed within the anterior and posterior capsule with little or no perinuclear cortex • Fusion of the nucleus and cortical matter and an elastic cortical plate (Fig. 22.23).

Fig. 22.23: Mature hard nucleus cataract. Note very minimal cortex

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Technique The first problem the surgeon is going to meet is a poor red reflex, particularly if the eye is darkly pigmented. The anterior capsule is very thin and atrophic and is likely to be on a stretch which can lead to the capsular tear running out to the periphery of the capsular bag. It is imperative that the anterior chamber is kept deep all the time and a retentive viscoelastic that is going to allow a smooth capsulorrhexis but at the same time being retentive has to be used. A combination viscoelastic is probably the best in this sort of situation, e.g. Duovisc (Alcon, Fortworth, Texas). In most instances it is possible with minor movements of the eye to view the edge of the capsulorrhexis tear as it is reflected by the microscope light. In some situations staining techniques of the capsule may be required and this will be discussed in further detail when white cataract phacoemulsification is discussed. It is important that a sufficiently large capsulorrhexis is made in order that the phacoemulsification tip does not inadvertently hit the capsular edge. The best phacoemulsification technique is still some form of divide and conquer, preferably dividing the lens into four quadrants and then engaging the apex of each quadrant and phacoemulsifying the quadrants deep in the capsular bag furthest away from the corneal endothelium. A phaco-chop maneuver of each quadrant can also be combined with this technique. Once the nucleus is cracked it allows easier access to each quadrant to carry out the phaco-chop. A 45-degree tip is used as it gives much better cutting power. It is important not to move the dense hard nucleus excessively and thus to minimize the movement, a shaving maneuver is used with the phacoemulsification tip. It is not advisable to engage the nucleus in any large chunk but to gradually trench the nucleus by shaving the surface and going deeper in that manner. It is important to be very patient in this technique as it will take time to achieve a deep enough trench. The depth of the trench can be judged by a white leathery reflex from the thick cortical plate. Once this reflex is obtained, cracking of the nucleus can then be undertaken. It is important also that when the cracking is done that all fibrotic bridges between the pieces are also broken. Any fibrotic bridge left will make it extremely difficult to manipulate the quadrants into the phacoemulsification tip. For further protection of the capsule it is possible to use viscoelastic as a pseudocortex and by injecting viscoelastic between the nucleus and the posterior capsule (Fig. 22.24). There should be free usage of the second instrument to stabilize the nucleus and the nuclear fragments in quadrants to prevent tumbling which might not only rupture the posterior capsule but also cause traumatic injury to the corneal endothelium. MATUR E

WHITE

CATARACT

The problem the surgeon faces in this sort of situation is that the white fluffy cortex obscures a clear view of the capsule. The capsule itself is thin and stretched and it is usually difficult to tell what type of nucleus lies within the capsular bag. The nucleus could be very dense or small and partially absorbed or large

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Fig. 22.24: Splitting of hard nucleus. All bridges between pieces must be broken by wide separation of the pieces

and flaky (Figs 22.25A and B). Once must also note that there is no epinuclear cortex to cushion the capsular bag. In general terms if the capsulorrhexis can be done then the phacoemulsification can be done. Capsulorrhexis Capsulorrhexis is the main problem as there is hardly any red reflex. Some steps that can be taken to minimize the chances of a poor capsulorrhexis is to use high magnification, have a very darkroom, start the capsulorrhexis in definite steps in the central portion of the capsule first. If the cortical “milk” starts to obscure the view of the tear then this can be flushed out or pushed to one side with the viscoelastic. Keep looking for the edge of the fold which is more easily seen as a linear reflex in the microscope light. Again, in this situation do not attempt to do too large a capsulorrhexis, in fact, err on the side of a small capsulorrhexis which can be extended if need be once the IOL has been inserted in the bag. Other Techniques of Visualization of the Anterior Capsule Other techniques that can be used are by • Using a retinal endoilluminator held outside the eye to enhance sclerotic scatter and therefore give a clearer view of the capsule. • To use various dyes and stains. Currently ICG has been described as being very successful in this technique. A few drops of dilute ICG are massaged onto the anterior capsule under air initially. The air is then exchanged and replaced with viscoelastic. Initially the capsule does not appear to be very easily seen but once a tear is made the dye enhances the edge of the torn capsule and it can be seen very easily.

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Figs 22.25A and B: Mature white cataract. Liquid cortex. Flaky, friable nucleus

Other dyes that have been described as being useful are gentian violet and methylene blue, trypan blue (Melles et al: JCRS 25:7-9, 1999). Hydrodissection Do not forget that there is no epinucleus to cushion the wave of fluid so hydrodissection has to be done very carefully. Also the nucleus can be small, hard and partially absorbed and this can float around the anterior chamber. Phacoemulsification The phacoemulsification in the vast majority of these white cortical cataracts is quite easy as the nucleus is usually very chalky and friable. However in some

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instances in the hard, partially absorbed nucleus this may have to be prolapsed into the anterior chamber to successfully phacoemulsify. Under these circumstances it is important that the corneal endothelium has been assessed in detail before any phacoemulsification in the anterior chamber is attempted. PSEUDOEXFOLIATION

SYNDROME

(PES)

The increased risk of cataract surgery in patients with pseudoexfoliation is well known. Potential causes of this increased risk include inadequate pupillary dilatation and a tendency for weak zonular attachment. There has also been recent articles which point to a significantly higher incidence of complications in patients with PES. Complications include zonular dialysis, posterior capsule rupture, an increased fibrinous reaction with posterior synechiae and IOL cell deposits. There is also a finding of increased postoperative inflammatory response in patients with PES. These studies have also found an impaired blood-aqueous barrier in these patients. Considering all the above it is important that the cataract surgery itself goes as smoothly as possible with minimum amount of trauma to tissue. The most pressing problem intraoperatively is one of loose zonular attachments. The important features pointing to weak zonular attachments intraoperatively include the following: a very fine powder-like deposits instead of flaky-like deposits on the anterior capsule; excessive folding of the anterior capsule as the capsulorrhexis is being done; excessive give in the capsular equator as irrigation aspiration is being done. If there is any concern that the zonules are loose then the options to the surgeon include the following • Place the IOL implant in the sulcus on top of the capsular bag (Fig. 22.26A). • Use a capsular tension ring, e.g. Morcher ring. These rings help to stabilize the lens in the capsule. The ring will spread out the capsule and distribute zonular force at the equator. In fact these rings act as pseudozonules. The ring itself can be put in the capsular bag at any time during the surgery and currently there are several injectors, e.g. Geuder Shooter which is used fairly successfully in placing the rings in the bag without difficulty. Capsulorrhexis It is always wise to start the capsulorrhexis away from the weak zonular zone. The initial zonular tear has been found to be the most stressful on the zonules and if a quadrant of capsule can be identified as having weak zonules. If an area of capsule can be identified as having weak zonules the capsular tear should be started 180° away from this area. Phacoemulsification In these situations where the zonules are weak it is important that not too much flow of fluid be going to the eye as this might cause further rupture of zonules and vitreous prolapse. It is imperative that the power of the phacoemulsification

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Fig. 22.26A: Pseudoexfoliation syndrome (PES). Weak zonules, IOL placed in sulcus

Fig. 22.26B: Late dislocation of IOL and capsular bag in PES

machine is increased but the flow within the eye is decreased. It is also important that the bimanual technique of phacoemulsification be used to help stabilize the cataractous lens. In summary, the key features in this type of case are • Proper placement of incision • Low flow phaco • High phaco energy • Use capsular tension ring.

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Intraocular Lens Type As pseudoexfoliation syndrome tends to have a much more pronounced inflammatory response, currently the lens of choice would be an acrylic implant, e.g. AcrySof (Alcon, Fortworth, Texas). This has been shown to cause the least amount of postoperative fibrotic metaplasia of the lens capsule which therefore minimizes the possibility of capsular contraction. Capsular contraction can occur many years down the track and cause dislocation of the IOL implant within the bag itself (Fig. 22.26B). The alternative of course is to use an anterior chamber lens or a sutured posterior IOL implant. TRAUMATIC

CATARACT

The most significant problem the surgeon will face with a traumatic cataract is one of loose zonules or partially subluxated cataracts. Associated with this there could also be other tissue abnormalities including dialysis of the iris root (Fig. 22.27). It is important that the surgeon attempts to minimize any further loss of zonules and therefore minimize the chance of vitreous prolapse into the anterior chamber. The clinical situation within the eye itself might be a contraindication of phacoemulsification which the surgeon has to make a very careful judgement on. If a wrong decision is made and there is substantial loss of zonular fibers then there is the possibility of the loss of the nucleus into the vitreous cavity or the lack of any support for foldable IOL implant.

Fig. 22.27: IOL Implantation in traumatic cataract. Note iris root dialysis and weak zonules

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Technique The placing of the incision is important in this situation and the placement should be avoided over the weak zonular area as the constant flow of fluid over this is usually maximal and also the constant placement of instruments into the eye can lead to further stretching and damage the zonules and cause vitreous prolapse. A low flow technique should be used coupled with a high phaco energy to minimize the amount of fluid within the eye and also minimize the amount of movement of the lens capsule complex in doing the phacoemulsification. A large capsulorhexis should be attempted again to minimize the amount of capsular movement during phacoemulsification. In all the situations it is advisable to use a Morcher ring to stabilize the capsule. A two-handed phaco technique is advisable. Capsulorrhexis The capsulorhexis itself should be started toward the weak zonular zone. The initial capsular tear is usually the most stressful to the zonules. The circular portion of the capsulorrhexis causes the least amount of tension on the zonules Phacoemulsification Before phacoemulsification proper, hydrodissection of the nucleus and capsulorrhexis must be done and free rotation of the lens must be obtained. Phacoemulsification is best done using a bimanual method in order that the cataract can be stabilized with a second instrument. The cataract itself is usually fairly soft and easy to phacoemulsify and requires very minimal amount of energy. However, if it is a hard cataract a large capsulorrhexis must be done in order that the phacoemulsification can possibly be done at the iris plane rather than in the capsular bag. In all these circumstances a very retentive type of viscoelastic, e.g. Viscoat (Alcon, Fortworth, Texas) should be used (Fig. 22.28A). Successful outcomes using this technique can be achieved even when there is more than 4 to 6 O’clock hours of zonular loss (Fig. 22.28B). Miscellaneous Cases High Myopia Patients undergoing cataract surgery who are also highly myopic and have a large axial length present with a special problem of a very deep anterior chamber as soon as the phacoemulsification tip is put into the eye. It is important that a short incisional tunnel to minimize the amount of striae. This should be done even if at the end of the procedure one has to use a suture to keep the incision water-tight. Low flow, high energy phaco is ideal in this situation. Of course in these patients there is also the possibility that there are weak zonules and again the use of a capsular tension ring, e.g. Morcher ring, should be considered. If the anterior chamber deepens excessively then it might be necessary to prolapse the nucleus into the anterior chamber and to phacoemulsify

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Fig. 22.28A: Dense mature cataract with weak zonular region

Fig. 22.28B: Successful IOL implantation. Note large area of absent zonules

in the anterior chamber. This should be done under good retentive viscoelastic, e.g. Viscoat, and also prior assessment of the corneal endothelium is important. POSTVITRECTOMY

PATIENTS

These patients present with very similar problems to the high myope patients and present with a deep anterior chamber, usually a very brunescent cataract and a small pupil. They also, not uncommonly have some damage to the zonules.

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Those that already have silicone oil or have the possible potential of having silicone oil used in the future, the type of IOL is important and currently acrylic implant is probably the best to be used in these patients. Other miscellaneous cases include patients with spinal deformities. These are handled by making the patient comfortable first and the surgeon then adapts his or her position to the patient’s position. It is not always necessary to have the patient lying flat to do a phaco cataract extraction (Fig. 22.29). SUMMARY As the surgeon’s expertise increases, these challenging cases can become more and more routine. It is very important that the surgeon is patient in handling these cases. A sound confident phaco technique is mandatory before attempting these more difficult cases. It is also important that the routine phaco technique the surgeon uses is also used for these difficult cases—thus the advantage of a two-handed phaco technique.

Fig. 22.29: Marked kyphoscoliosis patient unable to lie flat

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Keiki R Mehta Cyres K Mehta

Irrigation and Aspiration Following Phacoemulsification

23

INTRODUCTION The procedure of irrigation/aspiration refers to removal of the remaining soft cortical residue from the anterior chamber following nuclear removal. It is completed within the capsular bag at all times and is a closed chamber system. If the hydrodissection procedure has been carried out properly, the quantum of cortical residual material will be very minimal. The cortical material lines the bag and care needs to be exercised that during the removal phase the capsule is not inadvertently sucked into the aspirating port. Complete removal of the cortex leaves a perfectly clean chamber and minimizes the chances of postoperative inflammation on the day following the surgery. The functional recovery is much assisted and posterior capsulotomy is delayed. Irrigation/aspiration is thought of as very simple procedure. The surgeon finishes the nuclear removal part of the phacoemulsification and then relaxes, thinking, that with the removal of the nucleus, his main work is complete. He then goes on to irrigation/aspiration to clean out the cortical residue and breaks the capsule. It is an unfortunately, widely known, but least acknowledged, fact, that more capsules are broken by the surgeon at this, so-called innocuous stage, than all the capsules broken at the nuclear removal ultrasound stage. The guidelines for safe and efficient removal of the cortical material is to progress in small steps, at a virtually constant rate. Start with aspirating the cortex in one quadrant and gradually go around till you reach the starting point. Evaluating the flow characteristics of the cortex controls the quantum of aspiration vacuum. As the aspiration vacuum is increased it reaches a level where the cortex seems to “flow” into the port. At this point, it becomes simple to remove the cortex, as one needs to only move the aspiration port gradually in a circular manner.

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Sometimes the cortex is adherent to the posterior capsule especially when the hydrodissection has not been done properly. In these circumstances it becomes important to literally strip out the capsule piece by piece from the periphery to the center, using just adequate vacuum to hold the fragment. After a number of pieces have accumulated in the center, the vacuum is increased to aspirate them out together, all at one time. It is important that the maneuvers in the anterior chamber are kept to a minimum. Irrigation/aspiration is always done at the end of the surgery and the pupil will have started to contract by this time, hence inordinate delay will lead to further problems. Thus the irrigation/aspiration should be rapid while at the same time safety should not be compromised. BASIC PARAMETERS FOR COMMENCING IRRIGATION/ASPIRATION For aspiration to be performed correctly certain parameters need to be appropriately instituted • Appropriate tip size • Appropriate vacuum should be applied • Equilibrium between inflow and outflow should be perfect • Ability to alter suction to match the material and safety • Variable progression of quantum of suction. The vacuum to be generated at the aspirating tip is dependent upon the port size of the aspiration handpiece. The larger the port size, the lower should be the total vacuum limit and vice versa. The most common and widely used size is 0.3 mm. The standard operating parameters for an aspiration port of this size would be to keep the irrigation bottles at a height of 60 cm above the patient’s eye, and the vacuum set at 350 mm Hg in the “surgeon” mode (i.e. increasing with increased foot pedal depression) with a flow rate of 15 ml/min. Irrigation/aspiration handpieces come in two types: one which is complete metal in which the tip of the irrigation/aspiration is a single piece of shining metal (usually titanium), or the second type in which the aspirating tube is metal while the irrigation fluid is conducted via a silicone sleeve. Though it is usually a surgeon’s personal preference, however silicone does have its advantages. The silicone sleeve occludes the phaco port better thus maintaining a better anterior chamber; being flexible it matches the contours of the opening and thus reduces leakage. In addition it reflects less light. It has always been a point of debate on which is the ideal port size for the irrigation/aspiration technique. The diameter of the tips available is usually 0.2, 0.3, 0.5, or 0.7 mm. The former two tips are designed to be used with maximum vacuum limits (300 to 400 mm Hg), while the latter two tips need to be used with a minimum vacuum (100 to 200 mm Hg). With the larger size ports there is always a risk of anterior chamber collapse unless the irrigation/aspiration fluidics are perfectly balanced. The 0.3 mm orifice is usually an ideal port size as there is a good balance between the inflow and outflow thus maintaining the chamber well. In addition a 0.3 mm

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port would seem to be adequate for virtually all types of cortical debris. If the debris chokes the tip, a thin blade iris repositor inserted from the site port can either clean it or mash it into the port. THE IDEAL CIRCUMSTANCES FOR IRRIGATION/ASPIRATION The inflow and outflow must be balanced utilizing a flexible silicone test chamber prior to commencing surgery. The anterior chamber must remain formed and be kept deep. The pupil must be well dilated so that the I/A probe can have easy access to cortical material. There should be no source of pressure on the eye like an inappropriate lid clamp. The side and main ports should be of the appropriate size to minimize leakage. Adequate surge control facility must exist to prevent barometric changes in the chamber. The use of preservative free, intracardiac adrenaline (0.5 ml of 1/1000 adrenaline) injected into 500 ml of BSS has the ability to retain sufficient dilatation, and prevents the pupil from shutting down. THE BASIC SURGICAL PRINCIPLES OF CONDUCTING PROPER IRRIGATION/ASPIRATION Irrigation/aspiration can be conducted in many ways. However all the methods can be condensed into a simple basic technique, which is used at all times. Enter the anterior chamber using only irrigation, so that the chamber deepens, the capsular bag opens up, and the cortical remnants are easily available, and accessible, for removal. The aspirating port is then taken close to the material to be aspirated, only at this stage the suction is activated by the foot switch, which raises the vacuum so that the orifice becomes obstructed by the cortical material. The tip is moved towards the center of the chamber gently separating the cortex fragments. In the center of the anterior chamber, vacuum is enhanced so as to quickly aspirate the larger cortical clumps, which are free floating in the chamber. Each time aspiration is turned on and off with irrigation running, there are fluidic chamber changes. There is an alteration in the fluid balance of the anterior chamber in this process. When the cortical piece is attracted to the tip, the piece adheres to it, and then as the suction builds up, it is suddenly sucked in, producing surge. Unless the inflow is adequate the chamber is likely to collapse with dire consequences. Many phacoemulsification instruments have computerized surge controls (Alcon Legacy, Storz Millennium. Allergan Sovereign), automatically alter the speed of suction (by altering the speed of the peristaltic pump, in the Alcon and Allergan unit and the speed of the rotor in the Storz unit) to diminish or even eliminate this surge. In some instruments (Like the Opticon and the Mentor units) the use of the flexible diaphragm compensates effectively for the variation. As one analyzes the depth variants of the anterior chamber it becomes obvious that a great deal depends on two inputs, namely, the quantum of inflow and the quantum of fluid outflow. Inflow is dependent upon the diameter of the tube leading into the anterior chamber, the diameter of the connections and the size of the inflow

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ports. It is equally dependent upon the pressure, which is generated by the height of the bottle. The outflow is naturally dependent upon the size of the outflow port in the irrigation/aspiration handpiece, the quantum of vacuum or suction applied to the tip, the diameter of the vacuum tubing, and the firmness or stability of the walls of the tubing. There is also a certain amount of fluid loss, which occurs from leakage from the sides of the main and side port incisions. One always has to remember that the basic rule of aspiration namely that cortical material should be captured from the periphery and then subsequently drawn to the middle of the anterior chamber and then, and only then, by a burst of vacuum power, aspirated. The novice often tries to maintain a constant vacuum level which may at times lead to accidental aspiration of the capsule in the aspirating port leading to a capsular tear. There is another important rule that the aspirating orifice of the instrument must always be visible to the surgeon. This prevents accidental snagging and tearing of posterior capsule. In the event of an accidental miosis, though it is in order to go under the iris in a blind maneuver to hold the cortical fragments. However the fragments should be gently pulled outwards to the center of the pupil, at the same time visualizing the posterior capsule to be sure that no striae appear which would indicate that the capsule has been snagged. RECOGNITION OF POSTERIOR CAPSULE CAPTURE It is imperative during irrigation/aspiration that the surgeon recognizes immediately when the capsule inadvertently, has been captured in the aspirating port. It is important that when irrigation/aspiration is commenced, the focus of the microscope is changed so as to produce a sharp focus onto the posterior capsule, and the position of the eye with relation to the coaxial tube of the microscope be so adjusted so as to achieve the best possible red glow. If the focus is fixed on the posterior capsule the surgeon will realize immediately that the capsule is sucked into the port (captured) when thin and fine lines of folds, termed striae start from the point of capture with radial extensions. The appearance is very suggestive of a sunray appearance. If the capsule is caught in the middle it is easy to note that it has taken place, however if it is caught in the periphery, identification may prove difficult. The accidental capture of the posterior capsule is much easier and more frequent with the larger size ports like the 0.5 or the 0.7 mm size but comparatively less frequent with the smaller 0.2 or 0.3 mm ports. It is important that the moment capture is recognized the surgeon should immediately reverse fluid outflow to release the capture without moving the aspirating tip. Capturing the posterior capsule does not break the capsule (provided the port is smooth and well polished). It is the movement of the aspirating tip once the capture has occurred which breaks the capsule. Thus care should be taken that once the capture is detected, to freeze movement, stop aspiration and break the suction. Some of the better phacoemulsification machines are fitted with active venting capability, which permits an immediate break of vacuum with a positive outflow,

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which literally sweeps the posterior capsule away from the aspirating port. It is important that the surgeon is familiar with the controls and adapts himself to it so that at the critical time he does not fumble with the foot controls. Another quick technique to release the adhesion is to simply squeeze on the aspirating plastic/ silicone tube with the thumb and the forefinger, which also acts as an active venting technique. Care should however be taken to note that this technique will not work with the high vacuum tubing is available in such machines like the Alcon Legacy and the AMO Diplomax as the thickness of the tube is such that it simply does not get squeezed. It may be pertinent at this point to explain the principle of the flow rate setting on the phacoemulsification machine. Despite the volumes that have been written on the subject, a simple way of remembering is that flow rate settings controls the speed at which you work in the chamber. A slow flow rate (10 to 20 ml/min) means that it takes a much longer time to develop the level of vacuum you desire, while a fast flow rate (20-40 ml/min) indicates a very rapid onset of the suction. A good medium flow rate is 15 ml/minute. Whenever in doubt, slow down the flow rate and you will rarely get into trouble. ASPIRATION VARIABILITY FOR SUBINCISIONAL CORTEX REMOVAL One of the problems faced by both the novice and the experienced surgeon is the problem of removal of subincisional cortex. Customarily it tends to occur as the surgeon has, as one would say, “painted himself into the corner”, by removing the larger, easier to reach pieces first, leaving the removal of the subincisional cortex to the end. Usually the small clump left strenuously resists any efforts for its removal. Techniques for Subincisional Cortex Removal As a primary requirement the irrigation bottle should be raised a little higher so as to deepen the anterior chamber. The Ice-cream Scoop Maneuver The irrigation/aspiration handpiece should be inserted with only the irrigation on. The handpiece is then lifted 30 degrees vertically in an arc. The aspiration is energized, keeping a sharp lookout on the posterior capsule; the aspiration is gradually increased till the subincisional cortex pieces simply float out. The Bimanual Technique Go from the side port incision in a bimanual (two-handed) technique. Here we use two handpieces each with an individual, single function, either irrigation or aspiration. Hold the irrigation handpiece in the right hand, and the aspiration handpiece in the left hand. Enter via the side port and then gradually insinuate the aspirating needle under the capsule and simply draw out the offending cortical material. Alternate techniques such as the bent cannula (Binkhorst) are not as

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convenient. Various shaped cannulas have been developed with bends at strategic locations but the bimanual technique is the simplest and works exceptionally well. Many reputed surgeons do bimanual irrigation/aspiration as a routine technique with all their cases. The IOL Sweep Technique Place the intraocular implant in the eye and insert it in the bag. Fill the bag with viscoelastic and using a lens rotator, spin the IOL in the bag a few times. Very often the IOL loops will either clean the subincisional cortex out or make it so loose that it aspirates out fairly easily. IOL Compression Aspiration Technique Here after placing the IOL in the bag, simply rotate the loops away from the site of the subincisional cortex, fill the bag with viscoelastic, press on the surface of the implant with the irrigation/aspiration handpiece to deepen the chamber and push the posterior capsule backwards, energize the aspiration and the subincisional cortex will easily come out. The posterior capsule is not at risk as the IOL comes between the capsule and the I/A probe. Sometimes, in a difficult situation, the subincisional cortex simply refuses to come out, then the surgeon is left with the option that he can leave the piece behind and risk it reappearing later (usually between the 3rd and 7th postoperative days), in the visual axis, lying under or over the implant, appearing as soft, white, flocculent material appropriately termed as “cortical rain”. In this circumstance, the surgeon should re-enter the chamber through the previous phaco incision and using low suction aspirate the cortical “rain” out. It is always a fallacy to tell the patient that it will absorb by itself. It may, but by that time the patient is quite apprehensive and unhappy at the outcome of the surgery, in addition its presence leads to an irritable eye, and its absorption will invariably lead to early capsular thickening. With the present day litigious atmosphere in India, it makes more sense to simply aspirate it out. It leaves behind a happy patient and a relieved surgeon. MANAGING THE VITREOUS IN THE ANTERIOR CHAMBER Despite the best efforts of the surgeon an occasional capsular break will take place. It is important to learn how to handle this break, as its appropriate management will govern the quality of vision one will achieve. It is important that at the first sign of the break, the irrigation/aspiration handpiece be removed from the eye. If most of the cortical material has been removed it is important that first the intraocular implant be placed in the bag prior to removing the cortical residue. The logic behind this procedure is that while the bag has been unharmed the implant can easily be put in (bag fixation). In case the bag tears excessively, the implant can be put in the sulcus, i.e. on the anterior capsule (sulcus fixation).

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Subsequent aspiration is best done with the use of viscoelastic (dry aspiration). Fill the chamber with viscoelastic and with the left-hand; enter via a side port, using the bimanual aspirator (no irrigation). Gradually aspirate out the fragments, refilling the bag every time the chamber shallows. The big advantage of using viscoelastic is that it compresses the capsular tear opening preventing vitreous from coming out, and at the same time opening up the bag permitting easy access to the cortical remnants. In case the capsular tear has extended, as the surgeon, inattentively, did not recognize the tear in time, it is important to do a shallow anterior vitrectomy by placing the vitrector behind the posterior level (or to put it another way, deeper than the posterior capsule) and then do a little more vitrectomy to remove the vitreous at this location. Try not swirling with vitrector to the sides, as that would then damage whatever capsule is left behind. Subsequently either under air or with the use of Healon which acts as a tamponade onto the vitreous, holding it back, the implant loops can be moved into the bag to achieve a good fixation or alternatively, achieve a sulcus fixation by placing the IOL in front of the anterior capsule. CONCLUSION Irrigation/aspiration is an important step of cataract surgery and needs to be given the full, undivided attention of the surgeon. Caution and careful evaluation of the posterior capsule will go a long way in preventing complications from developing. Most phacoemulsifiers possess positive venting abilities and good chamber maintenance with excellent fluidic ability so as to permit this procedure to be done in a rapid, controlled fashion that is efficacious, yet completely safe. FURTHER READING 1. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-66, 1986. 2. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989. 3. Mehta KR: Clear corneal phaco with injectable silicone IOL proc. All India Ophthl Soc Proc (Mumbai) 1995. 4. Mehta KR: Phaco-levitation—a peaceful way. All India Ophthl Soc Proc (Chandigarh) 1996. 5. Mehta KR: Lollipop phaco cleavage—a new technique for hard cataracts. All India Ophthl Soc Proc (Bangalore) 1991. 6. Mehta KR: Phaco with flexible IOL—is it a step forward? All India Ophthl Soc Proc (Bangalore) 1991. 7. Mehta KR: SICS nonphaco—hydroexpression with an irrigating vectis. Proc of SAARC Conference, Nepal, 1994. 8. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 9. Mehta KR: Methylcellulose induced sterile endophthalmitis following phacoemulsification. Proc of SAARC Conference, Nepal, 1994. 10. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

Vijay K Dada Namrata Sharma Tanuj Dada

Foldable Intraocular Implants

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In a few months we will celebrate the 50th anniversary of the first intraocular lens (IOL) implantation performed by Harold Ridley on November 29, 1949, at St. Thomas Hospital in London.1 In 1984 Thomas Mazzocco implanted the first foldable IOL made of a silicone elastomer.2 Foldable IOLs are the most preferred introcular lenses. According to the 1997 ASCRS survey, 79% of the respondents said they were interested in putting foldable intraocular implants.3 The growing number of foldable IOLs can be confusing. If the main chemical components are analyzed, IOL materials can be divided into two groups; acrylate/ methacrylate polymers (Table 24.1) and silicone elastomers (Table 24.2). The first group contains rigid PMMA IOLs and the so-called soft acrylic and hydrogel lenses. The second group of IOLs are made of foldable polysiloxanes.The obvious use of small incisions for cataract surgery—low induced astigmatism, fewer postoperative complications, possible less inflammation, and faster rehabilitation of the patient—have encouraged the surgeons to use foldable IOLs. Silicone as an optic material came into vogue for small incision surgery because it can be folded, has good memory, is biocompatible and suffers little surface trauma.4,5 Silicone can be folded at 3 to 9 O’ clock meridian which is a twostep implantation or 6 to 12 O’clock meridian which allows the lens to be placed in a single maneuver. Posterior capsular opacification (PCO) occurs much later with silicone as compared to PMMA IOLs since the silicone optic is much thicker than the PMMA optic and therefore allows posterior capsule to be in close contact with the posterior side of the optic.7 Optic thickness is also responsible for an increased amount of pittings on the IOLs during Nd:YAG capsulotomy. However,

Three piece Three piece Three piece Three piece One piece, plate haptic Three piece One piece One piece, plate haptic

Acrylens ACR360 (Ioptex)

AcrySof MA60BM (Alcon)

Memory Lens U940A (Mentor)

92S (Morcher)

92C (Morcher) HOHEM

Hydroview H60M (Storz)

HydroSof SH30BC (Alcon)

ISH66 (Corneal)

HEMA

HEMA

HEMA/ HOHEXMA

MMA/HEMA

MMA/HEMA

HEMA

HEMA

PMMA

MMA/HEMA

Polypropylene

Polypropylene

PMMA

Polypropylene

Haptic Material

6.0

5.5

6.0

6.0

6.0

6.0

6.0

6.0

Optic Diameter (mm)

11.00

12.00

12.50

10.50

13.00

13.00

13.00

13.65

Total Diameter (mm)

119.0

118.4

118.3

118.1

118.1

119.0

118.9

118.5

1.44

1.44

1.47

1.46

1.46

1.47

1.55

1.47

38

38

18

28

28

20

<1

<1

A-constant Refractive Water Index Content* (percentage)

OF

MMA/HEMA/ EGDMA

PEA/PEMA

EA/EMA

Optic Material

THE ART

EA—Ethyl acrylate; EMA—ethyl methacrylate; PEA—2-phenylethyl acrylate; PEMA—2-phenylethyl methacrylate; MMA—methyl methacrylate; HEMA —2-hydroxyethylmethacrylate; EGDMA—ethylene glycol dimethacrylate; HOHEXMA—6-hydroxythexyl methacrylate

Design

Type

Table 24.1 : Intraocular lens specifications as provided by manufacturers (acrylate and methacrylate polymers)

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Design

Plate haptic Plate haptic with polyimide mini-loop Plate haptic Plate haptic 3 piece 3 piece 3 piece

Type

Chiron C10UB

Chiroflex C40UB

AA-4203

AA-4203F

Allergan S130NB

Allergan S140NB

Array SSM 26-NB

Silicone

Silicone

Silicone

Silicone

Silicone

Silicone

Silicone

Optic Material

Polypropylene

PMMA

Polypropylene

Silicone (foot plate positioning holes–1.15 mm)

Silicone (foot plate positioning holes–0.3 mm)

Polyimidie

Silicone

Haptic Material

6.0

6.0

6.0

6.0

6.0

6.0

6.0

Optic Diameter (mm)

13.0

13.0

13.0

10.5

10.5

11.5

10.5

Total Diameter (mm)

1.43

1.43

1.43

1.41

1.41

1.41

1.41

Refractive Index

Table 24. 2: Intraocular lens specifications as provided by manufacturers (Silicone elastomers)

<1

<1

<1

<1

<1

<1

<1

Water Content (percentage)

FOLDABLE I NTRAOCULAR I MPLANTS 255

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concerns over the biostability of the silicone IOLs soon developed. Silicone is hydrophobic, so it does not firmly adhere to the lens capsule.8,9 Therefore, silicone IOLs are considered to be unstable in the capsular bag. In fact, it is for this reason that silicone IOLs can decenter much more easily than a PMMA IOL. In a recent study, it has been clearly documented that decentration is the most important complication leading to explantation of silicone IOLs.9 Capsular capture, a complication, in which parts of the silicone optics come out of the bag, often occurs in eyes with silicone IOLs.8 Furthermore, silicone IOLs cannot be inserted in eyes where silicone oil has been instilled, as the two are not compatible with each other. Two types of silicone IOLs are presently in use: one-piece plate design and three-piece open loop designs. The three-piece design consists of a silicone optic and polypropylene loops/PMMA loops. Plate haptic design (Fig. 24.1) limits vitreous mobility by maintaining the original vitreous volume and also limits the rate of posterior capsulotomy10. This reduces the incidence of retinal detachment and cystoid macular edema after cataract surgery. The smaller spread in the location of the plate lens along the axis of the eye makes the A-constant more meaningful than that of loop lenses and results in better uncorrected visual acuities. The prerequisite for the implantation of these lenses is an intact rhexis and an intact capsular bag. If they are placed in a torn capsular bag or an early Nd:YAG capsulotomy is performed, the lenses dislocate into the vitreous. A newer plate haptic silicone IOL has haptic positioning holes which have larger diameter (1.15 mm) as compared to the previous plate haptic IOL (0.3 mm).10 The larger foot plate positioning holes significantly increase capsular bag fixation. Fusion of the anterior and posterior capsules through the larger positioning holes causes capsular fibrosis and resists capsular bag shrinkage. The three-piece haptic-anchor-plate intraocular lens is another modification to increase centration. The three piece has silicone haptic-anchor-plates that are 10.5 mm from tip to tip. At the distal end of each plate is a polyimide mini-loop. Thus, the overall length of the lens

Fig. 24.1: Plate haptic passport delivery system

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is 11.5 mm, which is 1.0 to 1.5 mm longer than the average ciliary sulcus or capsular bag. It fixates in the bag by fibrosis of the anterior capsular rim and posterior capsules around the mini-loops. Misplacement does not appear to cause serious decentration, which would be expected since the haptic-anchor plate is semi-rigid and will flex but not buckle, and the semi-rigid silicone component of the lens is the same length as the space into which it is being implanted. It is suitable for placement in the bag with or without tears in the anterior capsular rim or posterior capsule and, if necessary, for placement in the sulcus. This eliminates the need for a back-up lens for each implantation and means the lens can be implanted by less skilled surgeons and by those who do not perform phacoemulsification.11 Toric IOLs are also available in plate haptic design. These are cylindrical lenses used for correcting upto 3.5 D of astigmatism. The Memory Lens is a flexible IOL, the optic of which is made of poly-HEMA, thermoelastic acrylate material and polypropylene loops.12 The Memory Lens copolymer has a high refractive index (1.47), is hydrophilic and has a glass transition temperature of 25°C. The lenses have to be stored in a refrigerator ay 8°C. The prerolled lens slowly unfolds intraoperatively, taking about 10 to 15 minutes to unfold. Hydrogel lens is also available which is folded by the sure fold system (Figs 24.2 and 3) and is not a prerolled lens unlike the Memory Lens.

Fig. 24.2: Surefold folded hydrogel IOL

Fig. 24.3: Surefold folding system

The AcrySof lens is made of acrylate polymer. An acrylate polymer material has a relative high refractive index of 1.47, higher than that of silicone (1.41 to 1.46) or hydrogel (1.43) and comparable to that of PMMA (1.49). Acrylate has the highest index of refraction of any approved IOL. Thus, these lenses are the thinnest and should have the lowest bulk for a given dioptric power, edge and thickness. Soft acrylic IOL unfolds more slowly than other foldable lenses, so creases in the optic disappear over a longer time than creases in other foldable

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Fig. 24.4: AcrySof IOL being inserted

Fig. 24.5: AcrySof IOL being inserted

materials (Figs 24.4 and 5). In addition, cracks may form in the optic after prolonged and repeated folding procedures. Glistenings were associated when these lenses were packaged in Acrypak and not in the original wagon wheel and are highly influenced by temperature changes. Acrylic lenses have flexible polypropylene/ PMMA loops which provide satisfactory fixation and centration in the capsular bag, facilitate the aspiration of the viscoelastic from the bag at the end of surgery, and allows the lens to be implanted where surgery is complicated by a capsular tear or zonular rupture.13 It can also be implanted in the presence of silicone oil in the vitreous cavity. In this situation, implantation of a silicone IOL is contraindicated because a Nd:YAG capsulotomy cannot be done if the posterior capsule is in contact anteriorly with a silicone lens and posteriorly with silicone oil. Acrylic lenses produce considerably less amount of PCO (Fig. 24.6). This is because acrylic is biocompatible and bioactive material. According to the sandwich theroy,13

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Fig. 24.6: Anterior capsulorrhexis margin with foldable IOL

Fig. 24.7: Acrygel IOL to be folded

• The anterior capsule over the IOLs bioactive surface bends to the IOL directly or as result of the remaining lens epithelial cells (LECs) preventing their proliferation. Thus, the anterior capsule over the IOL remains clear. • Inside the bag, the remaining LECs proliferate and migrate behind the IOL. The 90 degrees edge of the IOL optic against the posterior capsule directs the proliferating lens epithelial cells to form monolayer between the IOL and the posterior capsule. Another bioactive bond is formed when a single LEC has the posterior capsule on one side and bioactive IOL surface on the other. The sandwich is formed and cell posterior capsule and cell bioactive IOL surface junctions prevent more cells from migrating behind the IOL. Recently a material which consists of both the acrylic and hydrogel lenses are available, i.e. an acrygel lens with winged haptics (Fig. 24.7).

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An Array IOL is a multifocal biconvex, 3-piece silicone IOL with polypropylene haptics and 6 mm optic diameter. A multifocal function is produced by five annular aspherical zones of refraction incorporated into a 4.7 mm diameter of the anterior surface.14 Each zone contains continuous curves of power with a 3.5 D range. Distribution of light varies with the pupil size as follows. • 50-60 % light is allocated to distance focus • 22-38 % at near focus • 15-18 % at the intermediate focus. Array IOLs have lower contrast sensitivity and more glare than PMMA IOL, this however may not be clinically significant. EXPLANTATION

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IOLs

Several possible events which may require explantation of IOLs include broken or bent haptics, linear glistenings on the lens that may give visual disturbances, damaged IOL secondary to folding or insertion problems and wrong IOL power.15 Unfortunately, the small incisions that foldable IOLs are placed through make it impossible to explant them in toto without enlarging the incision. Other clinical situations which may require early removal of foldable IOL include visually significant lens deposits or chronic endophthalmitis not responsive to medical therapy. Intraocular bisection of silicone IOLs is problematic because once in the eye, the lenses are slippery and resist any manipulation or folding attempts.15 Koch’s bisector can be used which allows easy and controlled cutting.15 Unlike silicone IOL, acrylic surfaces are sticky and can therefore be cut into two halves with scissors or folded and explanted through the initial incision.16 FUTURE

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IMPLANTS

Future would consist of various modifications in the current foldable lens materials and designs to induce greater biocompatibility, accommodation and inhibition of PCO.17 This would also include the modifications in the existing holders and folders (Fig. 24.8). The collamer for aphakic lens material that has a great potential and is undergoing investigative study. This is the material that has been used in the implantable contact lens. The collamer elicits very little PCO or anterior capsulorrhexis metaplasia and fibrosis. It is a user-friendly material. Materials for multifocal IOLs most likely will evolve to include the use of polymer comixtures that can give a gradation of refractive indices. Polymer engineering includes creating a central 3 mm of a lens from one polymer with a specified refractive index and the peripheral 3 mm of it with a different polymer and a different refractive index. If the lenses are manufactured with the two polymers that has a determined rate of diffusion into each other, such that a gradation of refractive indices from the periphery to the center of the lens exists, this could produce multifocality. Other possibilities include “smart molecules” or isomers that might change their refractive index with the application of certain wavelengths of light. A laser

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Fig. 24.8: Holders and folders for foldable IOLs

at some wavelength on the implant can alter its refractive index and, thereby, its power. Stereoisomers might be another option for aphakic lenses. Stereoisomers, with different refractive indices in equilibrium with each other in a given lens can undergo a shift in equilibrium with delicate application of laser light to alter the equilibrium mixture, and thus the refractive index and achieve multifocality, perhaps astigmatism correction, or just a new refractive power. The truncated edge of the AcrySof is now largely felt to be responsible for the lower incidence of PCO seen with the implant. Another modification for such a lens might be a matte finish to its equatorial region. The matte finish might help to reduce the undesirable optical images reflected from the AcrySof’s sharp edge. In future, idea is to implant two separate devices. An endocapsular ring may be placed into the equatorial portion of the capsular bag. If this ring is designed with a truncated edge, it is possible to inhibit cell migration, as with the AcrySof lens. Another interesting aphakic design involves a new accommodative IOL. The lens itself is positioned in the most posterior part of the capsular bag space and against the vitreous face. It is fixed into place by instilling atropine for 3 weeks postoperatively. The lens is 11.5 mm in length with polyimide loops for fixation and centration. It has hinges at the optic-haptic junction that allow the optic to freely move backwards and forwards. Only 1 mm of forward movement equals 2 D of refractive changes. The combination of polymer materials and innovative designs offers almost limitless possibilities in aphakic technology. REFERENCES 1. Ridley H: Intraocular acrylic lenses. Trans Ophthalmol Soc UK 71: 617-21, 1952. 2. Mazzocco TR: Early clinical experience with elastic lens implants. Trans Ophthalmol Soc UK 104: 578-79, 1985. 3. Leaming DV: Practice styles and preferences of ASCRS members-1997 survey. J Cataract Refract Surg 22 : 931-39, 1996.

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4. Menapace R, Amon M, Papapanos P et al: Evaluation of the first 100 consecutive PhacoFlex silicone lenses implanted in the bag through a self-sealing tunnel incision using the Prodigy inserter. J Cataract Refract Surg 20 : 299-309, 1994. 5. Knorz MC, Lang A, Hsia T, et al: Comparison of the optical and visual quality of poly (methylmethyacrylate) and silicone intraocular lenses. J Cataract Refract Surg 19 : 766-71, 1993. 6. Kohnen T: The variety of foldable intraocular lens materials. J Cataract Refract Surg 22(2): 125558, 1996. 7. Mamalis N, Phillips B, Kopp CH et al: Neodymium: YAG capsulotomy rates after phacoemulsification with silicone posterior chamber intraocular lenses. J Cataract Refract Surg 22(Suppl 2): 1996. 8. Kimura W, Kimura T, Sawada T et al: Postoperative decentration of three-piece silicone intraocular lenses. J Cataract Refract Surg 22(Suppl 2): 1996. 9. Auffarth GU, McCabe C, Wilcox M, et al: Centration and fixation of silicone intraocular lenses— Clinicopathological findings in human autopsy eyes. J Cataract Refract Surg 22(2):1281-84, 1996. 10. Mamalis N, Omar O, Veiga J et al: Comparison of two plate-haptic intraocular lenses in a rabbit model. J Cataract Refract Surg 22(2):1291-95, 1996. 11. Colin J: Clinical results of implanting a silicone haptic-anchor-plate intraocular lens. J Cataract Refract Surg 22(2):1286-90, 1996. 12. Potzsch DK, Losch-Potzsch CM: Four year follow-up of the Memory Lens. J Cataract Refract Surg 22(2): 1336-42, 1996. 13. Shugar JK: Implantation of AcrySof acrylic intraocular lenses. J Cataract Refract Surg 22(2):135559, 1996. 14. Weghaupt H, Pieh S, Skorpik C: Visual properties of the foldable array multifocal intraocular lens. J Cataract Refract Surg 22(2):1313-17, 1996. 15. Koch HS: Lens bisector for silicone intraocular lens removal. J Cataract Refract Surg 22(2): 137980, 1996. 16. Koo KY, Lindsey PS, Soukiasian SH: Bisecting a foldable acrylic intraocular lens for explantation. J Cataract Refract Surg 22(2):1381-82, 1996. 17. Fine H: Focus on the future of aphakic lenses. Ophthalmology Times 1-4, 1999.

Eric J Arnott

History of Lens Implantation

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INTRODUCTION The current history of lens implantation dates back to the 1940s during the Second World War. In the war British fighter pilots frequently, among other serious injuries, had their eyes damaged with intraocular fragments from either their goggles, or canopy of their damaged aircraft. There are several documented reports of these pilots who flew either Hurricane or Spitfire fighter planes. Harold Ridley, at that time a young ophthalmic surgeon with an appointment in St Thomas Hospital, London, realized that the retained fragments of polymethylmethacrylate (PMMA) in the eye remained inert over the ensuing years. He had been considering idea of “curing aphakia” with the insertion of a lens implant in patients having cataract surgery. In consultation with ICI, who made the plastic for the aircraft canopies and Rayners Optical, he produced the world’s first lens implant using this material. This was inserted into the eye of a patient having a cataract extraction, in November 1959, at St Thomas Hospital. The original Ridley lens made of PMMA was one piece and diskoid shaped, very like the human lens. While at this time the intracapsular cataract operation was the one currently performed, Harold Ridley was yet again very advanced in his thinking. The operation was performed in conjunction with an extracapsular procedure. With sophisticated irrigating-aspirating systems not being available for removal of the soft lens cortex, this operation was limited to patients with a mature cataract. The extracapsular procedure was relatively simple and quick. Under topical anesthesia using cocaine 4% guttae and with homatropine 2% guttae, to dilate the pupil, the eye was opened using a Graefe’s knife. This knife penetrated the

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corneoscleral junction in the 3 O’clock meridian and exited at the 9 O’clock junction, keeping in this plane the knife swept along the corneoscleral junction to emerge from the eye in the 12 O’clock meridian. As much as possible of the anterior capsule was removed in one bite, using “extracapsular” toothed forceps. The nucleus was expressed from the eye in one piece and the residual cortex removed with saline irrigation. The lens was then implanted, into this posterior chamber. While the initial results with this lens were excellent with no undue postoperative reaction it was relatively too heavy, being ten times heavier than current implants, and commonly dislocated into the vitreous cavity. Due to this problem after over 100 lenses had been successfully implanted this form of lens implant surgery was abandoned. In a retrogressive step succeeding lens designs were placed in the anterior chamber, usually in association with an intracapsular extraction. The result was that lens implantation entered the doldrums years for the next two decades. Poor lens materials and defective design caused many eyes to be lost, usually on account of corneal decompensation. The one-piece lens was modified to have a PMMA optical portion with the addition of nylon haptic loops. The distal portion of these haptics lying within the angle of the anterior chamber often rubbed against the endothelial layer of the cornea. Progressive loss of these cells, in even one area, would in time reduce the endothelium to such a low cell count that they could not maintain the relative dehydration and integrity of the cornea. An associated problem occurred with the gradual degradation of the nylon loops, which in time caused even greater instability of the lens. SUBSEQUENT

MODIFICATIONS

Modifications were made, with the lens once again being one-piece PMMA, with the haptic portion being fixated in the recess of the anterior chamber. These early modifications did not rectify the complications associated with peripheral endothelial corneal touch. Peter Choice solved the problem by producing a lens with a gullwing configuration to the distal portion of the haptic which kept it clear to the cornea. His style of lens modified by Tennant for the American market and Kelman giving if flexible loop haptics survives till the present time. It is currently used as a phakic lens for correction of myopic and hypermetropia errors of refraction. In the late 1960s Binkhorst developed the “iris clip lens” which could, like the anterior chamber lens, be used in conjunction with either an intra or extracapsular extraction. With this style of lens the PMMA optic was supported by two sets of haptic loops which gave pupillary support fixation. In the original design of this lens, the loops gained fixation within the pupillary margin and the optical portion was prepupillary. Many modifications of these lenses were designed on the concept of pupillary fixation. Svyatoslav Fyodorov produced the “Sputnik” lens, so named as it appeared on the market at the same time as the first Russian satellite. Jorg Boberg-Ans and Eric Arnott made modifications with lenses, which had one-piece optics and posterior haptics in the posterior chamber, while retaining

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the anterior loops. The Arnott lens had the anterior loops at right angles to the posterior haptics while the Boberg-Ans lens had the loops in line. A further design was made by Sanford Severin. If adequate pupillary fixation was achieved, good visual results were obtained. Frequently these lenses dislocated forwards into the anterior chamber or posteriorly into either the posterior chamber or vitreous cavity. Moreover fundus examination was difficult. In 1974 Binkhorst and Worst claimed that the compartments of the eye remained more stable with less “phakodonesis” in the presence of an extracapsular extraction. As a result of their observations most surgeons, at this time, converted from intracapsular extraction to extracapsular extraction. Binkhorst like Ridley before him realized that the intact posterior capsule could act as a support for lens implant fixation. This led Binkhorst to develop a lens similar to his iris clip, but with the anterior loops removed. This lens depended for its fixation on the posterior capsule while still retaining an optical portion that was prepupillary. The introduction of a one-piece PMMA lens with two integral solid haptics in 1974 by John Pearce heralded the return to posterior chamber lens implantation. It had taken 25 years, from the time of the original surgery by Harold Ridley in 1949, for surgeons to finally realize that the ideal position for an implant was in this area, where “The Almighty” had originally placed the “human” lens. Arnott, who at this time was actively working with Pearce at Charring Cross Hospital, London modified the bipod lens to a tripod, known as the Little-Arnott. Pearce also modified his lens to a tripod haptic design. These two lenses, manufactured by Rayners of England, gained a considerable market in the United Kingdom. William Harris of Dallas, the USA modified this design with a lens that was one piece, with quadrangular haptics. The rigidity of all these lenses did not allow for the variabilities of the diameter of the retropupillary space. If fixation did not occur on the posterior capsule some element of decentration could occur. Posterior chamber lens implantation was totally revolutionized with the reintroduction by Steve Shering, in 1976, of a three-piece, mono plane, lens with optics of PMMA and two-loop haptics which were flexible; allowing for the variations of the dimensions within the posterior chamber of the eye. Shering introduced the “methodology” of placing a flexible loop lens into the posterior chamber of the eye, a system of surgery that has been upheld until the present day. This lens was almost identical to the Barroquer lens produced some twenty years earlier, for anterior chamber lens insertion. It differed fundamentally in that the haptic loops were made of polymethylmethacrylate and not nylon. They were non-biodegradable and therefore did not dissolve. The Shering lens determined the course of lens implantation for the next decade. Modifications of this style of lens were designed Robert Richard Sinskey, William Simcoe, Dick Kratz, John Sheets and others. All these lenses were three-piece with PMMA optics and two haptic loops of varying configuration, requiring the presence of the posterior capsule for their fixation and an extracapsular cataract extraction. During the latter part of the 1970s and throughout the whole of the 1980s cataract surgery was undergoing a progressive change from simple

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extracapsular extraction of the lens to “small incisional phacoemulsification and lens implantation”. Both of these procedures lended themselves very well to these forms of lens implantation. With the implants of this period having rigid optics of 5 mm diameter or more, if “phako” was used, the section into the eye, had to be enlarged for the insertion of the implant. With all operations performed with extracapsular cataract extraction, whether with one piece removal of the nucleus, or “phako” postoperative problems often occurred due to opacification of the lens capsule. This was associated, in the first instance, with proliferation of the anterior subcapsular cells damaged during the making of the anterior capsulotomy undergoing metaplasia to form “pseudofibroplasts”. These cells, with the inflammatory reaction in the early postoperative period, could form opacification of the posterior capsule within the first weeks after surgery. Later opacification of the posterior capsule occurred from the spread of retained fornix cells germinating and spreading centripedally over the posterior capsule. While the proliferation of these traumatized anterior cells, becoming fibroblasts, could aid in fixation of the lens implant, the proliferation of the germinal cells were no more than an obstacle for vision. Simcoe in 1982 had shown that a prolene loop lying on the posterior capsule of the lens could inhibit centripetal spread of germinating fornix cells over its surface. These concepts led Arnott to produce a lens with totally encircling PMMA loops, which, on contact with the posterior capsule, would block the spread of these germinal cells to the optic axis. At the same time good fixation could be achieved by the pseudo-fibroblasts produced by the traumatized anterior capsular cells. The first one-piece flexible PMMA lens was introduced in 1980 by Arnott, and Jaffe with totally encircling one-piece PMMA loops. This style of lens with various modifications and manufactured by Alcon dominated the American market for a number of years. Other important lens styles at this time included the Anis totally encircling loop lens and the one-piece lenses made with soft material such as the “Iogel”. All these lenses relied on posterior capsular membrane support. With all forms of extracapsular cataract extraction (ECCE), be it one-piece removal of the nucleus, or “phaco”, the configuration of the anterior capsulotomy was inexact. As a result the haptics of the lens could lie either on the exposed surface of the posterior capsule or actually within the confines of the capsular bag. David Apple of the Storm Eye Institute showed some signs of decentration. With the variability of fixation of the opposing loops, either on the posterior capsule, or within the capsular bag decentration could occur. Lenses with the maximum arc of contact on the posterior capsule such as the Jaffe, Arnott, Anis or Simcoe showed the least incidence of decentration. RECENT

ADVANCES

The most dynamic change in the procedure came with the introduction of the capsulorrhexis perfected by Thomas Neumann and Howard Gimbel in 1987. This enhanced the concept of posterior chamber lens implantation. Not only was the

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implant placed within the posterior chamber of the eye but it was inserted, through the round capsulorrhexis opening of the anterior capsule, to lie within the confines of the lens capsular bag itself. In this surgical procedure of small incisional cataract extraction, removal of the nucleus by ultrasound or laser is obligatory. The implants currently available can be used in conjunction with this procedure, but having optics of 5 mm or more in diameter require an enlargement of the incision for their insertion. This has led to the introduction of lenses being made with soft materials such as silicone, poly-HEMA, or acrylates, which can be folded, for insertion into the eye. Polymethylmethacrylate lenses, with slimmed-down optics, can also be used. The present format of cataract and implant surgery encompasses a small incisional procedure, with a capsulorrhexis, and insertion of an implant totally within the confines of the capsular bag.

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Tetsuro Oshika

Implantation Techniques of Acrylic Foldable Intraocular Lens and its Clinical Results

26

INTRODUCTION Acrylic foldable intraocular lens (IOL) (AcrySofTM, Alcon Laboratories Inc., Fig. 26.1) is composed of a copolymer of phenylethylacrylate and phenylethylmethacrylate which is crosslinked with 1,4 butanedial diacrylate. 1 The IOL retains many of the advantageous physical properties of polymethylmethacrylate (PMMA), but is able to be folded. Its unique characteristics include a high refractive index of 1.55, making it the thinnest lens possible without compromising the optic diameter, and slow, controlled unfolding. The records of safety and efficacy of acrylic foldable IOL have been increasingly accumulated. Fig. 26.1: Acrylic foldable intraocular The advent and widespread distribution lens (AcrySofTM, Alcon Laboratories Inc) of foldable IOL have significantly contributed to the growing and renewed interest in phacoemulsification. This was particularly true for acrylic foldable IOL, since it was not before the introduction of this lens to the market that a great deal of interest was generated and directed to small incision cataract surgery. Even though the silicone IOLs had been available for more than a decade, the combination of phacoemulsification and foldable IOL was not yet widely accepted.

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This chapter describes the technique of implantation, management of intraoperative or postoperative complications, and clinical results of acrylic foldable IOL. IMPLANTATION There are two models of acrylic foldable IOLs available: MA60BM and MA30BA. The MA60BM has a 6.0 mm optic with overall length of 13.0 mm, while the optic of MA30BA is 5.5 mm in diameter and overall length is 12.5 mm. Since MA30BA’s optic is thinner and softer, folding is easier than MA60BM, but unfolding process tends to take longer. There are several views about the incision size required for the implantation of acrylic foldable IOLs, including the claim as small as 3.2 mm.2 However, the wounds are often enlarged by the IOL implantation procedure,3,4 and too tight incision might damage the optic. The author measured the width of scleral incision before and after the implantation of acrylic foldable IOLs, and found that the minimum wound size after the implantation was 3.8 mm for MA60BM and 3.5 mm for MA30BA. Therefore, I use the 3.75 and 3.5 mm short-cut steel knife to prepare the wounds for MA60BM and MA30BA, respectively. A study using cadaver eyes reports similar data.5 Several forceps have been designed for the implantation of acrylic foldable IOL and are available in the market. The author prefers the combination of F300 folder (Micra) and blunt implantation forceps (TMI), which enables reproducible folding and precise intraoperative manipulation. Using the implantation forceps, the optic edge is lightly held and the IOL is taken out from the container (Fig. 26.2). Cares must be taken not to scrape the optic with the tip of forceps, since scratches are easily formed. The IOL is then horizontally placed on the plate of F-300 folder (Fig. 26.3) so that the optic edge correctly corresponds to the inner angle of the plate, leading to symmetrical folding of the lens. If the optic edge fails to fit the plate (Fig. 26.4), the lens will be folded asymmetrically (Fig. 26.5), necessitating a wider incision for implantation (Fig. 26.6).

Fig. 26.2: The lens is taken from the container. If the tip of forceps scrapes the optic, some scratches may be formed

Fig. 26.3: The IOL is horizontally placed on plate of the folder

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Fig. 26.4: The optic edge does not match the plate angle

Fig. 26.5: Inadequate placement of the optic (Fig. 26.4) results in asymmetrical folding

Fig. 26.6: Asymmetrically folded lens (right) requires a wider incision than properly folded lens (left)

Fig. 26.7: The folder is closed and the lens is folded

By closing the folder, the lens is bent as shown in Fig. 26.7. The folder’s design eliminates the risk of popping out of the lens as well as upside-down folding. The folded lens is then grasped by the blunt implantation forceps. The slit on the jaw of folder indicates the appropriate location to grasp (Fig. 26.8). Usually, the upper most part of the slit is the appropriate position (Figs 26.9 to 11). If too peripheral portion of the optic is grasped (too low down), the lens may be caught between the forceps in the eye, necessitating a second instrument to release the lens from the forceps. Tucking of the leading haptic is not necessary. By pronating (rotating counterclockwise) the hand and implantation forceps, the leading haptic is placed into the tunnel and inserted into the anterior chamber (Fig. 26.12). At this point, the closed part of the optic is on the left side. As the optic enters the tunnel, the implantation forceps is redirected posteriorly so that the distal haptic is inserted beneath the opposite anterior capsule margin and into the capsular bag (Fig. 26.13). The longer the tunnel is, the more posteriorly the surgeon should try to direct

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Fig. 26.8: Side view of the closed folder

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Fig. 26.9: The lens is grasped by the blunt implantation forceps through the slit

Fig. 26.10: The positioning of the grasping forceps relative to the slit on the folding forceps. The upper most part of the slit is the appropriate position to grasp

the forceps. It is very important to guide the distal haptic into the capsular bag before the whole optic enters and opens in the anterior chamber. Once the leading haptic is placed beneath the capsulorrhexis margin, the implantation forceps is rotated clockwise (Fig. 26.14). Opening the forceps allows the optic to slowly unfold and be disengaged from the forceps (Fig. 26.15). By depressing and rotating the optic with the implantation forceps (Fig. 26.16), the proximal haptic is implanted into the capsular bag (Fig. 26.17). The non-slippery

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Fig. 26.11: The lens is held and ready for implantation. Excessive pressure is not necessary to keep folding the lens. The loop should not be folded inside the optic (tucking)

Fig. 26.12: By pronating (rotating counterclockwise) the hand and implantation forceps, the leading haptic is placed into the tunnel and implanted into the anterior chamber. The closed part of the optic is on the left side

Fig. 26.13: As the optic enters the tunnel, the implantation forceps is redirected posteriorly so that the distal haptic is inserted beneath the opposite anterior capsule margin and into the capsular bag. It is very important to guide the distal haptic into the capsular bag before the whole optic enters and opens in the anterior chamber

Fig. 26.14: Once the leading haptic is placed beneath the capsulorrhexis margin, the implantation forceps is rotated clockwise

Fig. 26.15: Opening the forceps allows the optic to slowly unfold and be disengaged from the forceps

nature of the acrylic foldable optic facilitates this procedure. Instead of the forceps, a lens hook may be used for the implantation of trailing haptic.

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Fig. 26.16: The optic is depressed and rotated by the implantation forceps

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Fig. 26.17: The proximal haptic is implanted into the capsular bag

Fig. 26.18: Adequate positioning of the optic within the implantation forceps is crucial for smooth insertion procedure (A). If the forceps grasp too peripheral portion of the optic (too low down, B), a second instrument is needed to release the lens which had been caught between the forceps. If it is too central (too high, C), a stressful force will be exerted on the folded portion of the optic, which may possibly result in the cracking or fracturing of the lens

Adequate positioning of the optic within the implantation forceps is crucial for the smooth insertion procedure. If the forceps grasp too peripheral portion of the optic (Fig. 26.18), the lens may be caught between the forceps (Fig. 26.19) and a second instrument is needed to disengage the lens (Fig. 26.20). If it is

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Fig. 26.19: Left : standard unfolding. Right: the lens is engaged between the forceps due to inadequate grasping location

Fig. 26.20: A second instrument is needed to release the lens which had been caught between the forceps

Fig. 26.21: Since the forceps does not cover the optic sufficiently, the leading edge of the optic forms “ fish mouth”, preventing smooth entr y through a small incision

too central (Fig. 26.18), a stressful force will be exerted on the folded portion of the optic, which may possibly result in the cracking or major damaging of the lens. As for the horizontal positioning of the forceps, forceps is supposed to cover just the entire width of the optic. If the tip of forceps remains far inside the lens edge, the leading edge of the optic will form “fish mouth”, preventing the smooth entry through a small incision (Fig. 26.21). On the other hand, when the forceps exceed the edge too much, the tip of the forceps may be unnecessarily captured by the tissue within the scleral tunnel. Several other instruments are available for implantation of acrylic foldable IOL. The folding forceps shown in Figure 26.22 engages both edges of the optic by

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Fig. 26.22: Paddle-type folding forceps

Fig. 26.24: By closing the forceps, the lens is folded into halves

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Fig. 26.23: Both edges of the optic is held by the groove made on the inner wall of the jaw

Fig. 26.25: The lens may be folded using two straight or curved forceps without any specially designed folders

the groove made on the inner wall of the jaw (Fig. 26.23). By closing the forceps, the lens is folded into halves (Fig. 26.24). The lens may be folded using two straight or curved forceps (Fig. 26.25) without any specially designed folders. Curved type implantation forceps (Fig. 26.26) may facilitate the disengagement of the lens from the forceps within the eye, since they will produce a wider space between the jaws (Fig. 26.27), making the lens capture less likely. However, a wider Fig. 26.26: Curved implantation forceps incision is needed for the passage of this forceps due to its configuration, and intraocular maneuverability (i.e. rotating the lens) is not as good as the straight forceps. Cross-action forceps will produce

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PHACOEMULSIFICATION even wider space between the jaws (Figs 26.28 and 29). There is a report that MA30BA can be implanted with an injector designed for silicone IOLs.6 At the present writing, a new injector system for acrylic foldable IOL is being developed (Figs 26.30 to 35). INTRAOPERATIVE

Fig. 26.27: Curved type forceps facilitates the disengagement of the lens from the forceps within the eye, since they produce a wider space between the jaws. However, a wider incision is needed for the passage of this forceps due to its configuration, and intraocular maneuverability (i.e. rotating the lens) is not as good as the straight forceps

Fig. 26.28: Implantation with cross-action forceps

COMPLICATIONS

In cases of posterior capsule rupture, acrylic foldable IOL can be implanted out of the capsular bag. When capsulorrhexis margin is intact, it is easy to place the IOL on the anterior capsule. If the remaining capsular and zonular supports are insufficient, trans-scleral suture fixation will be considered, for which acrylic foldable IOL can also be used. Since the optic of acrylic foldable lens is more fragile than other foldable IOLs

Fig. 26.29: Cross-action forceps produce wider space between the jaws

including silicone lens,7 tight incision, prolonged and/or repeated folding, and extremely firm grasping sometime result in scratch formation7,8 or cracking/fracturing of the optics (Figs 26.36 and 37).9-11 Incorrect instrumentation can be the causative factor of this phenomenon in some cases.12,13 Except for a rare case in which extremely severe damage occurred,11 ordinary crack formation does not necessitate explantation of the acrylic foldable IOL. This is because mild to moderate linear cracks are not likely to affect the optical quality of the lens.14 An experimental study indicated that the modulation transfer function

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Fig. 26.30: An injector system for acrylic foldable IOL (Monarch TM IOL Delivery System). The system consists of two parts: an autoclavable, reusable titanium handpiece and a sterile, singleuse cartridge

Fig. 26.31: The cartridge is filled with viscoelastic, immediately prior to loading the lens into the cartridge

Fig. 26.32: The optic edge of the lens is grasped with the holding forceps and the lens is placed anterior side up into the back of the cartridge

(MTF) and resolving power of acrylic foldable IOL were not affected by a few linear cracks created on the optic (Fig. 26.38).14 Likewise, prolonged folding had little influence on the optical quality of the lens (Fig. 26.39). EXPLANTATION Explantation of acrylic foldable IOL might be necessary in some cases, possibly due to inadequate power calculation, severe damage of the lens, malpositioning of the lens, and so on. There are two ways to explant the acrylic foldable lens

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Fig. 26.33: The lens should be inserted until it is centered with the outline etched into the top of the cartridge. The trailing haptic will extend from the proximal end of the cartridge. With forceps closed and both blades extending across the optic, press down gently and evenly on the top optic surface, ensuring the lens is positioned on the bottom surface of the cartridge. Accurate positioning of the lens will decrease the potential for optic and haptic damage

Fig. 26.34: The cartridge is inserted into the handpiece (1) and the cartridge is fully slid forward into the handpiece slot (2)

Fig. 26.35: Advance the plunger in one slow motion, ensuring that the plunger goes either above or below the trailing haptic. The plunger should make initial contact with the cartridge at the ramp

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Fig. 26.36: A linear crack formed on the optic. Patient’s vision is not affected

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Fig. 26.37: A linear fracture of the optic developed during repeated foldings and attempts to insert the lens through a very tight incision

Fig. 26.38: Modulation transfer function (MTF) with linear cracks created at the central 3 mm zone of the optic surface using a cutter. With cracks up to 10 lines per 3 mm, there were no noticeable changes in MTF. When 10 or more cracks were created, MTF worsened significantly at all spatial frequencies

through the original unenlarged small incision; intraocular bisection15 and re-folding in the anterior chamber.16 The acrylic foldable IOL can be easily cut with conjunctival or Vannas scissors. The procedures are as follows: First, the anterior chamber is filled with viscoelastic material, and the lens is rotated out of the capsular bag into the anterior chamber. Two Sinskey hooks may be used, one of which is inserted underneath the optic to lift the lens. Then additional viscoelastic material is injected under and over the IOL. While the

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Fig. 26.39: Modulation transfer function (MTF) measured after prolonged folding of the acrylic foldable IOL. Measurements were taken 30 minutes after unfolding. MTF was not affected significantly by any procedures

Fig. 26.40: While the distal edge of the optic is supported by the hook inserted through the side port, the scissors are introduced to bisect the optic

Fig. 26.41: Care should be taken not to damage the posterior capsule and corneal endothelium

distal edge of the optic is supported by the hook inserted through the side port (Fig. 26.40), the scissors are introduced to bisect the optic (Fig. 26.41). Care should be taken not to damage the posterior capsule and corneal endothelium. The two pieces of the divided lens is now grasped with toothed forceps and removed from the anterior chamber through the original small incision (Figs 26.42 and 43). There is another way to cut the optic. If a quarter is removed (Fig. 26.44), the remaining three quarters will be explanted through the unenlarged incision by rotation around the wound.

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Fig. 26.42: The lens is completely divided into halves

Fig. 26.44: A quarter has been cut and removed

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Fig. 26.43: The two pieces of the divided lens is grasped with toothed forceps and removed from the anterior chamber through the original small incision

A technique has been reported to refold the acrylic foldable IOL in the anterior chamber.16 Although this technique also enables the explantation of acrylic foldable IOL through the original or slightly enlarged incision, IOL bisection seems less complicated and traumatic. Acrylic foldable IOL strongly adheres to the lens capsules.17 Adhesion force is significantly higher than PMMA and silicone IOLs. When extensive adhesion between the IOL and the surrounding ocular structures exists, the explantation surgery will be more complicated and difficult.16 Therefore, the explantation or exchange surgery of acrylic foldable IOL, if necessary, should be performed before a long interval from the primary surgery. It is supposed that the critical time point is 2 to 3 months after the implantation surgery.

DATA

As reported previously, postoperative courses are highly satisfactory.18 Postoperative visual acuity data were analyzed in 200 eyes of 200 patients who underwent phacoemulsification and implantation of acrylic foldable IOL. As shown in Figure 26.45, more than 95 percent of patients achieved best-corrected visual acuity (BCVA) of 20/40 or better, and more than 80 percent attained the level of 20/20. The results of uncorrected visual acuity (UCVA) were excellent likewise. Interestingly and importantly, the incidence of posterior capsule opacification (PCO) is extremely low with acrylic foldable IOL. Our analysis of posterior

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Fig. 26.45: Postoperative corrected visual acuity analyzed in 200 eyes. More than 95 percent of patients achieved 20/40 or better, and the majority attained the level of 20/20

Fig. 26.46: Kaplan-Meier analysis of posterior capsule opacification. The survival rate goes down when Nd:YAG laser posterior capsulotomy is performed. The YAG rate is lowest with acrylic foldable IOL, and there were significant difference among groups (p=0.008, log-rank test)

capsulotomy rate in 876 eyes indicated that the rate is lowest with acrylic foldable, followed by PMMA and silicone IOLs (Fig. 26.46). Statistically significant differences were found among groups (p=0.008, log-rank test). In many cases, not only the

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Fig. 26.47: An eye at 6 months after the implantation of acr ylic foldable IOL. Both the anterior and posterior capsules remain highly clear

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Fig. 26.48: An eye at 3 years after the implantation of acr ylic foldable IOL. While anterior capsular margin is slightly opaque and there are some cell proliferation outside the optic, posterior capsule retains complete clarity

posterior capsule but the anterior capsule remains clear for years (Figs 26.47 and 48). With the acrylic foldable IOL, pearl type PCO occurs in some cases (Fig. 26.49), but fibrosis type PCO is rarely seen. In general, pearl type PCO is easier to dissect with Nd:YAG laser than fibrosis type PCO. Moreover, acrylic foldable IOL is highly resistant to the Nd:YAG laser damage.1 Thus, posterior capsulotomy is safely performed on acrylic foldable IOL with the least risk of Fig. 26.49: Nd:YAG laser posterior capsulotomy was performed on the pearl type PCO “pit” formation on the optic, which is a rather seen with acrylic foldable IOL common observation with silicone IOLs.19 Centration of the acrylic foldable lens is also excellent. Figure 26.50 demonstrates the degree of decentration measured in 18 silicone, 23 PMMA and 22 acrylic foldable IOLs at 6 months, postoperatively. These features of acrylic foldable IOL, i.e. lower PCO rate and better centration, seem to be attributable, at least in part, to the strong adhesion of this lens to the lens capsules. An experimental study has shown that acrylic foldable IOL adhered to the capsule most strongly, followed by PMMA IOL, while silicone IOL showed no adhesion.17 Histologic observation suggested that acrylic foldable IOL inhibited the lens epithelial cells (LECs) and lens fibers at the optic edge from proliferating and migrating toward the center of the posterior capsule (Fig. 26.51). Adhesion of the anterior capsule to IOL optic is another factor (Fig. 26.52). A recent study has shown that a phenomenon called capsular capture, in which parts of the IOL optic slip out of the capsular bag and the edge of the anterior

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Fig. 26.50: Decentration of IOLs measured 6 months after surgery in eyes with silicone (n=18), PMMA (n=23) and acrylic foldable IOLs (n=22). *p<0.01

Fig. 26.51: The IOL having strong adhesion to the capsule (above) inhibits the lens epithelial cells (LEs) and lens fibers at the optic edge from proliferating and migrating toward the center of the posterior capsule. Inflammatory mediators in the aqueous humor may also be refrained from entering the capsular bag and interacts with LECs

Fig. 26.52: If the anterior capsule does not adhere to the anterior surface of IOL, the edge of the anterior capsule tends to slip underneath the IOL and makes direct contact with the posterior capsule. Cases with this phenomenon exhibits a significantly higher incidence of PCO, especially fibrosis-type PCO which extended from the attachment of anterior capsular edge to the posterior capsule

capsule makes direct contact with the posterior capsule, frequently occurred in eyes with silicone IOL.20 Occurrence of this condition seemed to reflect the lack of adhesion between silicone IOL and the anterior capsule, and cases with capsular capture exhibited a significantly higher incidence of PCO, especially fibrosis-type PCO which extended from the attachment of anterior capsular edge to the posterior capsule.20 The direct contact between the anterior and posterior capsules accelerates migration of LECs lining the anterior capsule onto the posterior capsule.21,22 These observations confirm our clinical impressions that, in cases with acrylic foldable IOL, anterior capsular edge more frequently remains attached on the optic and

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that fibrosis type PCO is very rare. Strong adhesiveness of acrylic foldable IOL can explain these situations. The adhesive force to the lens capsule differs significantly among IOL materials, resulting in different effects on the behavior of LECs and lens fibers. A more adhesive material such as acrylic foldable appears to retard the source of PCO from extending to the visual axis on the posterior capsule, possibly by acting as a mechanical barrier and/or minimizing capsule-wrinkling and limiting the space between the IOL and capsule. Adhesiveness may facilitate centration of the lens.17 On the other hand, adherent nature would be of disadvantage in performing explantation of the IOL, in case it is necessary. However, IOL explantation is a rather rare condition, and we believe that appropriate adhesion will enhance overall stability of the IOL within the eye. The design of the IOL edge can be another important factor. The acrylic foldable IOL has a sharp, rectangular optic edge (Fig. 26.53). It has been reported that this edge creates sharp, rectangular bend in the lens capsule, which induces contact inhibition to migrating LECs and therefore reduces PCO.23,24 This edge effect has also been reported with PMMA IOL.25 A previous study indicated that the sharp optic edge creates higher pressure on the posterior capsule and acts as a barrier to lens epithelial cell migration.25 As for acrylic foldable IOL, creation of a sharp bend in the capsule and inhibition effect of migrating LECs depend not only on optic design but also on IOL material and surgical technique.24 The various factors involved are IOL design (sharp rectangular edges, posterior convexity, and steep loop angle), IOL material (adhesiveness and less fibrosis [biocompatibility]), and surgical technique (well-centered CCC smaller than the IOL optic and removal of LECs).24 Regarding IOL design, a sharp rectangular optic edge appears crucial, and posterior convexity and a steeper loop angle may enhance this. Regarding IOL material, adhesiveness and less fibrosis, especially at the optic edges, may help maintain the bend. Thick fibrosis at the optic edges makes the capsule rigid and inflexible and might hinder tight wrapping of the lens capsule around the optic edges, possibly dulling the angle of capsular bend.

Fig. 26.53: The acrylic foldable IOL’s sharp edge creates a sharp rectangular bend in the posterior capsule (arrow), where migration of LECs is inhibited.24

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On the other hand, strong, thick anterior capsular fibrosis and phimosis may affect capsular shrinkage and result in tighter wrapping of the capsular bag around the entire IOL. Regarding surgical technique, creating a well-centered CCC smaller than the optic of an IOL is crucial, so the capsular edges along the entire circumference are in apposition to the IOL optic. This may allow creation of an optimal capsular bend at the sharp, rectangular optic edges.24 CONCLUSION Acrylic foldable IOL is the most inert lens in the eye that the author has ever seen. In addition to the advantageous characteristics mentioned in this chapter, postoperative inflammation has also been found to be less with acrylic foldable IOL.18 One possible drawback of this lens is the relatively large incision size when compared to that of silicone IOL. However, with the advent of newer and more sophisticated wound architectures as well as the introduction of the 5.5 mm diameter optic lens, this drawback is far outweighed by the advantages. The introduction of new injector system will further add to the advantageous feature of this lens. As shown in the recent statistics, acrylic foldable IOL has been dramatically gaining its popularity among the cataract surgerons,26,27 and this trend will continue in the coming years. REFERENCES 1. Koch DD: Alcon AcrySof acrylic intraocular lens. In Martin RG, Gills JP, Sanders DR (Eds): Foldable Intraocular Lenses. Slack: Thorofare, 1993. 2. Shugar JK: Implantation of AcrySof acrylic intraocular lenses. J Cataract Refract Surg 22:1355-59, 1996. 3. Steinert RF, Deacon J: Enlargement of incision width during phacoemulsification and folded intraocular lens implant surgery. Ophthalmology 103:220-25, 1996. 4. Mackool RJ, Russell RS: Effect of foldable intraocular lens insertion on incision width. J Cataract Refract Surg 22:571-74, 1996. 5. Kohnen T, Lambert RJ, Koch DD: Incision sizes for foldable intraocular lenses. Ophthalmology 104:1277-86, 1997. 6. Miller KM, Grusha YO, Ching ECP: Injecting the Alcon MA30BA lens through a Staar 1-MTC45 cartridge. J Cataract Refract Surg 22:1132-33, 1996. 7. Milazzo S, Turut P, Blin H: Alterations to the AcrySof intraocular lens during folding. J Cataract Refract Surg 22:1351-54, 1996. 8. Vrabec MP, Syverud JC, Burgess CJ: Forceps-induced scratching of a foldable acrylic intraocular lens. Arch Ophthalmol 114:777, 1996. 9. Carlson KH, Johnson DW: Cracking of acrylic intraocular lenses during capsular bag insertion. Ophthalmic Surg Lasers 26:572-73, 1995. 10. Pfister DR: Stress fractures after folding an acrylic intraocular lens. Am J Ophthalmol 121:572-74, 1996. 11. Lee GA: Cracked acrylic intraocular lens requiring explantation. Aust NZ J Ophthalmol 25:71-73, 1997. 12. Baldeschi L, Rizzo S, Nardi M: Damage of foldable intraocular lenses by incorrect folding forceps. Am J Ophthalmol 124:245-47, 1997. 13. Bee JA: Cracking of acrylic intraocular lenses during capsular bag insertion. Ophthalmic Surg Lasers 27:327, 1996. 14. Oshika T, Shiokawa Y: Effect of folding on the optical quality of soft acrylic intraocular lenses. J Cataract Refract Surg 22:1360-64, 1996. 15. Koo EY, Lindsey PS, Soukiasian SH: Bisecting a foldable acrylic intraocular lens for explantation. J Cataract Refract Surg 22:1381-82, 1996. TM

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16. Neuhann TH: Intraocular folding of an acrylic lens for explantation through a small incision cataract wound. J Cataract Refract Surg 22:1383-86, 1996. 17. Oshika T, Nagata T, Ishii Y: Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone and acrylic foldable materials: an experimental study. Br J Ophthalmol 82:549-53, 1998. 18. Oshika T, Suzuki Y, Kizaki H et al: Two year clinical study of a soft acrylic intraocular lens. J Cataract Refract Surg 22:104-109, 1996. 19. Newland TJ, Auffarth GU, Wesendahl TA et al: Neodymium:YAG laser damage on silicone intraocular lenses—a comparison of lesions on explanted lenses and experimentally produced lesions. J Cataract Refract Surg 20:527-33, 1994. 20. Hayashi K, Hayashi H, Nakao F et al: Capsular capture of silicone intraocular lenses. J Cataract Refract Surg 22:1267-71, 1996. 21. Apple DJ, Solomon KD, Tetz MR et al: Posterior capsule opacification. Surv Ophthalmol 37:73116, 1992. 22. Nagamoto T, Hara E: Lens epithelial cell migration onto the posterior capsule in vitro. J Cataract Refract Surg 22:841-46, 1996. 23. Nishi O, Nishi K, Sakanishi K: Inhibition of migrating lens epithelial cells at the capsular bend created by the rectangular optic edge of a posterior chamber intraocular lens. Ophthalmic Surg Lasers 29:587-94, 1998. 24. Nishi O, Nishi K: Preventing posterior capsule opacification by creating a discontinuous sharp bend in the capsule. J Cataract Refract Surg 25:521-26, 1999. 25. Nagata T, Watanabe I: Optic sharp edge or convexity—comparison of effects on posterior capsular opacification. Jpn J Ophthalmol 40:397-403,1996. 26. Leaming DV: Practice styles and preferences of ASCRS members—1998 survey. J Cataract Refract Surg 25:851-59, 1999. 27. Oshika T, Amano S, Araie M et al: Current trends in cataract and refractive surgery in Japan— 1997 survey. Jpn J Ophthalmol 43:139-47, 1999.

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J Stuart Cumming

The Mini-loop Plate and Accommodating Lenses

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Before discussing the modified plate lens, the mini-loop lens and the accommodating lens, it is necessary to understand the advantages and disadvantages of standard plate lenses. The STAAR Surgical 4004 Sulcus Plate Lens This first silicone lens was developed and designed for sulcus placement. Its commercial life preceded capsulorrhexis and thus implantation was in conjunction with a beer-can capsulotomy. Care had to be taken to ensure that the thin haptics were placed in the sulcus. Misplacement of one or both haptics into the bag resulted in the “Z-syndrome” with severe tilting of the optic necessitating lens exchange. This was the major complication of this lens design. Other complications resulted from its sulcus placement which placed the lens plates in close proximity to the iris. This could result in chafing and iris pigment dispersion and, in rare cases, pigmentary glaucoma. In my experience with implantation of 600 of these lenses, these complications, with the exception of the Z-syndrome, did not cause serious clinical problems necessitating lens exchange. As a result of the Z-syndrome complication of the 4004 STAAR plate lens, the company thickened the plate to 0.25 mm. This occurred at the same time that Gimbel and Neuhann discovered the anterior capsulotomy technique of capsulorrhexis. The implantation of the modified plate lens, the STAAR surgical model 4203, allowed the lens with the thicker and stiffer plates to be implanted into the capsular bag with capsulorrhexis without the complication of the Z-syndrome.

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The STAAR Surgical and Chiron Vision 4203 and C10: Identical Plate Lenses The lenses are 10.5 mm long, the approximate length of the empty capsular bag. The haptics are 0.25 mm thick, thick enough to prevent buckling with fibrosis but still sufficiently resilient to allow the haptics to flex with fibrosis of the anterior capsular rim, with its resultant end-to-end compression of the plates. Since the fibrosed anterior capsule is tough and leather-like, the plates cannot vault anteriorly. Thus, they flex in a posterior direction, placing the optic of the lens up against the vitreous face. The complications of modern cataract surgery are retinal detachment, cystoid macular edema (CME) and opacification of the posterior capsule. Opening the opacified capsule with a YAG laser further increases the risk of retinal detachment and CME.1 The capsular bag in a 70-year-old is approximately 5.0 mm deep, yet the IOL occupying this space is at the most only 1.3 mm thick. A space is therefore left that is filled with aqueous if the optic locates posteriorly or by the enlargement of the vitreous cavity allowing movement of the solid vitreous forward if the optic locates anteriorly. An IOL locating anteriorly greatly increases the mobility of the solid vitreous and can result in retinal detachment and CME.2 It is a reasonable assumption that designing an IOL that locates in the posterior part of the capsular bag, thereby stabilizing the vitreous, will result in a low incidence of both retinal detachment and CME. The posterior location of the plate IOL is caused by shrinkage of the capsular bag during fibrosis, “shrinkwrapping” the lens. This exerts end-to-end pressure on the plates, which flex. They cannot flex anteriorly because of the fibrosed leather-like anterior capsule and therefore they flex posteriorly. This pulls the elastic posterior capsule tightly against the posterior convex surface of the optic, greatly reducing the rate of opacification of the capsule with a resultant decrease in the need for a YAG capsulotomy2,3 further reducing the risk of retinal detachment and CME. We know that the incidence of retinal detachment with intracapsular cataract surgery was 3.5 percent and with uncomplicated extracapsular surgery with some containment of the vitreous, it was less than 1 percent. The incidence of retinal detachment has been reported to be much less than this and with a very low incidence of CME and opacification of the posterior capsule1-3 with the currently available plate hepatic lenses from STAAR Surgical, Model 4203, and Chiron Vision, Model C40.6 At Anaheim Eye Medical Group, both plate and loop lenses were implanted. The charts of pseudophakic patients who developed a retinal detachment were examined over a seven-year period. There were 16 detachments: all sixteen were in patients implanted with a loop lens, five of these were implanted into a torn capsular bag without vitrectomy. The remaining 11 were implanted into an intact bag with capsulorrhexis—exactly the same procedure as the plate lens implantations. During this period of time, there were 1857 loop lenses implanted versus more than 3000 plate lens implantations. There is, therefore, a significant reduction in the incidence of retinal detachment with the posterior-locating and thus vitreous-stabilizing plate lens. The identical plate haptic silicone IOL’s, Chiron Vision’s Model C10 and STAAR Surgical’s Model C4203, therefore have major advantages over loop lenses. These

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lenses have to be placed into an intact capsular bag with capsulorrhexis. However, plate haptic lenses have significant disadvantages in that they do not fixate in the bag and therefore can dislocate into the vitreous if there is a tear in the bag or if a capsulotomy is performed too early. In addition, there is the need to have a back-up loop lens for each patient implanted with the plate lenses.2 This increases costs and plate lenses with their advantages can only be used by highly skilled surgeons. Decentration The 10.5 mm length of the lens is approximately the same as the average capsular bag. The plate is semirigid and cannot buckle, like the sulcus placed early lenses of STAAR Surgical (the 4004 lenses). Decentration is therefore limited to the difference between 10.5 mm and the largest bag diameter which is approximately 11.0 mm; that is, 0.5 mm. Loop lenses have overall lengths ranging from 12.0 to 14.0 mm and impinge on the vascular ciliary muscle through the cul-de-sac of its capsular bag. The ciliary muscle in pseudophakes is still functional and when the pseudophakic eye attempts to focus at near, the involuntary ciliary muscle contracts forcing the pliable loops centrally. If, during the period of fibrosis, one or both loops cannot either be compressed equally centrally or retract equally into the bag cul-desac, the lens decenters. Location Along the Axis of the Eye Cumming and Ritter4 investigated the location of plate lenses and long loop lenses along the axis of the eye (Fig. 27.1).

Fig. 27.1: Location of plate lenses and long loop lenses along the axis of the eye

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Figure 27.1 demonstrates two highly significant findings: (i) the 1.3 mm thick optic of the plate lens consistently locates in the posterior part of the 5.0 mm deep bag space, thereby stabilizing the vitreous, and (ii) the optics of the plate lenses have a much smaller spread along the axis of the eye than the optics of long loop lenses. With plate lens implantation, 50 percent of the time, the vitreous cavity is shortened; therefore, its volume is decreased, and in cases where the vitreous cavity is lengthened by as much as only 0.75 mm, this distance corresponds to less than 5 percent of its preoperative length. On the other hand, the longloop lenses decrease the vitreous length 20 percent of the time. Eighty percent of the time, the vitreous cavity length is increased; the largest increase in length is 2.17 mm. The anterior location of a large percentage of long-loop lenses, therefore, increases the mobility of the remaining solid vitreous. The spread of the location of plate lenses in this study was 1.45 mm and the loop lense spread 3.15 mm. Approximately 1.0 mm change in location of the optic can change the effective power of the lens by as much as 2.0 diopters. Because of the large spread in the location of the optic along the axis of the eye, the ‘A’ constant of plate lenses should be more meaningful than loop lenses and the uncorrected acuities are superior.2 Many of the refractive surprises encountered with long-loop lenses can therefore be accounted for by the location of the optic—in myopic surprises in the anterior, and hypermyopic surprises in the posterior range of the spread of optic locations along the axis of the eye. The Mini-Loop Lens Design The mini-loop lens was designed to maintain the advantages of plate lenses and yet allow the lens to fixate in the bag. The plates into which the mini-loops are anchored are 10.5 mm from end-to-end and 0.25 mm thick—the same length and thickness as the STAAR 4203 and Chiron C40 plate lenses. The mini-loops, made of either polyimide or silicone, project from each end of the plates by 0.5 mm, giving the lens an overall length of 11.5 mm. The capsular bag is between 10.0 and 10.5 mm in diameter and the sulcus is about 10.5 mm in diameter. The lens is therefore slightly longer than either. The loops therefore project minimally from the ends of the plates but enough to gently engage the periphery of the capsular bag or sulcus. Silicone has a specific gravity close to that of the aqueous and is therefore weightless within the eye. Gentle pressure on the periphery of the bag will therefore hold the lens in position until the lens is fixed in position by fibrosis around the loops. The loops are designed to exert as little pressure as possible on the periphery of the bag since this part of the bag is close to being in contact with the highly-vascular ciliary muscle which, despite the fact that the eye is aphakic, constricts just as the pupil does when patients change their fixation from far to near, and relaxes when fixation changes from near to far. Long-loop lenses have overall loop lengths from 12.0 to 14.0 mm—much longer than the bag space. These long loops, especially

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if they are stiff, distort the capsular bag and impinge on the ciliary muscle through the distorted bag and can result in irritation and inflammation with constriction and relaxation of the ciliary muscle. It is reasonable to assume that the loops can be flexed towards the center of the eye when the ciliary muscle constricts as the patient looks at a near object. This can happen during fibrosis and cause decentration of the long-loop lenses.2,5 The VS2 and VS5 UV lenses (Figs 27.2 and 3) are designed so that the semirigid plates into which the mini-loops are staked are stiff enough to withstand buckling but can flex with fibrosis to cause the optic to locate in the posterior part of the capsular bag.2 The less pressure the loops exert on the ciliary muscle, the less irritation and less likelihood of postoperative inflammation. The pressure exerted by the loops is designed to be just sufficient enough to hold the lens perfectly centered while fibrosis fixes the lens in position, but at the same time to ensure that the loops will not press into the ciliary muscle through the bag wall.

Fig. 27.2: The VS2 UV intraocular lens

Fig. 27.3: The VS5 UV intraocular lens

Clinical Results The VS 2 UV 6.0 mm Lens Profs Jochen Kammann and Joseph Colin6,8 and Mr Patrick Condon implanted these lenses during the initial clinical trials. The lens implantations reported by Mr Condon were performed by surgeons in training, and several lenses were

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implanted into torn bags, into the sulcus, and three had one haptic in the bag and one in the sulcus with minimal decentration. The lenses fixed in the bag and did not dislocate into the vitreous. He called the lens a universal lens or a “lens for all seasons,” meaning that it has the advantages of both plate and loop lenses. He reported that the lens can be placed into the sulcus or torn bag and even when misplaced into the bag/sulcus, did not cause serious problems. It can therefore be used safely by surgeons of all levels of skill thereby giving the patients the combined advantages of plate and loop lenses and reducing the overall complication rate of cataract surgery.7 The VS 2 uv 6.0 mm model was designed with polyimide loops. A one-piece lens with silicone loops may be a superior design since the silicone loops are softer than polyimide and will be more gentle on the tissues. This one-piece silicone lens should function just as well as the polyimide loop lens in causing the lens to center well and fixate in the bag. Such a lens, the VS 5 uv 5.0 mm optic lens has been implanted by Prof Albert Galand of Liege, Belgium and Prof Jochen Kammann of Dortmund, Germany. Both surgeons found minimal inflammation and perfect centration.8 Prof Kammann reported that a 5.0 mm optic is adequate and that the lens can be inserted through an incision of less than 3.0 mm, further reducing complications. Measurements of the vitreous cavity length pre and postoperatively indicated a postoperative shortening in 22 out of 23 eyes measured by ultrasound.8 The VS5 design therefore stabilizes the vitreous the majority of the time. It should be noted that standard foldable loop lenses have their loops staked into the optic, and when the distance between the stakes in the optic in these lenses from different manufacturers is measured, the distance is less than 5.0 mm (Table 27.1). The VS 5 uv 5.0 mm optic zone is therefore larger than the optical zone of the long-loop lenses since the loops are staked into the haptic anchor plate rather than the optic and the smaller optic can be implanted through a smaller incision. Description of the C and C Vision Accommodating Refractive Lens TM Model AT-45 The C and C vision multi-piece IOL is a modified plate haptic silicone lens. The lens is hinged adjacent to the optic and has small polyimide haptics (Fig. 27.4). Table 27.1: Optical zones of loop lenses Lens AcrySof AMO SI-18 Chiron C31UB Chiron/IOLAB L141UB Medevec VS2* Medevec VS5+ Pharmacia/Iovision Pliolens

Optic (mm)

Optical zone (mm)

6.0 6.0 6.25 6.0 6.0 5.0 6.0

* Optical zone is 5.25 mm or larger up to 27.0 diopters (D) +Optical zone is 5.0 mm up to 26.5 D

4.8 4.5 4.46 4.76 6.0 5.0 4.6

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PHACOEMULSIFICATION The overall length of the lens is 11.5 mm (loop-tip to loop-tip measurement), while the overall length as measured from the ends of the plate haptics is 10.5 mm. The optic diameter is 4.5 mm, and the ‘A’ constant is 119.0. Principle Supporting the Mechanism of Action of the Accommodating Lens

It is known that approximately 20 to 25 percent of pseudophakic patients can read with their distance correction9 and significantly more patients can see at near without any correction. 10 This latter group’s near vision is aided by either some degree of myopia, againstthe-rule (ATR) myopic astigmatism, a small pupil or a combination of any of the three factors. There have been papers reporting TM a myopic shift during the early Fig. 27.4: Accommodating Refractive Lens model AT-45 postoperative period. 9 During this period the anterior capsule of the lens is undergoing fibrosis and adherence to the posterior capsule, fixing the lens in the bag. It is during this early postoperative period of fibrosis that myopic shift and decentration can occur. The pseudophakic patient is constantly attempting to change focus, resulting in constriction and relaxation of the ciliary muscle. In aphakic patients examined by slit lamp during accommodation, the intact vitreous face can be seen to bulge forward. The constant constriction and relaxation of the ciliary muscle during the period of fibrosis causes intermittent increases of vitreous pressure, forcing the optic of three-piece loop lenses to locate in the midcavity of the capsular bag space, which in a 70-year-old measures 5.0 mm front to back.11 In most cases, this force on the IOL overcomes the posterior angulation of the loops of threepiece long loop lenses. By slit-lamp observation, variations can be seen in the location of the optic of these lenses within the 5.0 mm bag space. Some optics locate immediately behind the iris, resulting in an unexpected myopic postoperative refraction, and about 20 percent locate posteriorly and are in close contact with the vitreous face through the posterior capsule, producing a hypermyopic postoperative refraction. The 20 percent of three-piece long loop lenses locating posteriorly corresponds to the 20 percent of these patients, demonstrating some accommodation.4,9

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Three-piece loop lenses usually have a length of 12.5 mm or more. The loops are longer than the diameter of the bag and therefore distort and elongate the capsular bag. As a result of this capsular bag elongation, the loops are directly in contact with the ciliary muscle. I believe that as the ciliary muscle contracts and relaxes during the period of fibrosis, two forces are exerted on the “inthe-bag” IOL: (i) the loops are compressed centrally and as fibrosis proceeds, one or both loops can become asymmetrically distributed in the capsular bag, resulting in possible decentration of the optic, and (ii) the vitreous pressure increases with ciliary muscle contraction by the redistribution of the muscle’s mass which encroaches on the vitreous cavity space. This can push the optic forward, overcoming the posterior angulation of the loops, causing it to fix in a location anterior to the original posterior surface of the human lens (myopic shift). The Chiron C10 and STAAR 4203 plate lenses and the SI18 loop lens from Allergan are all manufactured from silicone with a refractive index of 1.41. The plate lenses are uniplaner while the SI18 loop lens is vaulted posteriorly. It would be expected that the posteriorlyvaulted loop lens would have the highest ‘A’ constant since it is designed to vault posteriorly. However, the plate lenses have an ‘A’ constant of 119.0 and the SI18 posterior-vaulted lens has an ‘A’ constant of 117.2. Therefore, there are forces within the eye that cause the plate lenses to vault posteriorly during fibrosis and the loop lens optic to be moved anteriorly (myopic shift). Decentration of three-piece long loop lenses, I believe, is caused by ciliary muscle contraction and relaxation during the period of fibrosis. I do not believe the so-called “peapod” effect exists. This belief is based upon the excellent centration of the accommodating lenses after paralysis of the ciliary muscle following the use of topical atropine for the first three weeks postoperatively. A series of studies has shown that plate lenses consistently locate in the posterior part of the bag space.4,5,8 When the anterior capsule’s ectodermal cells undergo fibrosis, end-to-end pressure is exerted on the plates; they have to flex. They cannot flex anteriorly because the leather-like anterior capsular rim crosses the plate. They therefore have to flex posteriorly, locating the optic against the vitreous face. Treating the patient with atropine for three weeks postoperatively paralyzes the ciliary muscle, thereby eliminating the anteriorly-biasing forces. This allows the optic of the AT-45 accommodating lens to locate in the most posterior position, preventing decentration and allowing the polyimide loops to fixate in the bag periphery. When the ciliary muscle constricts, its mass is redistributed and encroaches on the vitreous cavity.12 This results in an increased vitreous pressure and movement of the lens equator forward.12,13 The weakest part of the wall of the vitreous cavity, the part most susceptible to movement upon increased vitreous pressure, is the optic of the C and C vision AT-45 lens since there is a groove or hinge across the plates adjacent to the optic. The optic is pulled posteriorly to the distant position by relaxation of the ciliary muscle, which stiffens the fibrosed anterior capsular rim covering the plates thus forcing the optic backward.

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The optic thus moves forward and backward upon constriction and relaxation of the ciliary muscle. This is an involuntary muscle action controlled by the autonomic nervous system. Studies by ‘A’ scans and UBM have shown anterior movement of the optic with ciliary muscle contractions.14,15 The vitreous cavity length is longer and the “AC depth,” which is the distance from the cornea to the posterior surface of the IOL, is shortened after the administration of pilocarpine.14 The 4.5 mm Optic of the AT-45 Accommodating Lens An optic of 4.5 mm was chosen for the AT-45 lens, since the longer the plates the more likely it is that the optic will locate in its maximal posterior position8 especially if the ciliary muscle is paralyzed during the period of fibrosis. An optic of 4.5 mm is considered adequate for the following reasons: • The optic of the lens is the optical zone; it is unencumbered by staking of loops. • The optic zone of all staked three-piece lenses is less than 5.0 mm (Table 27.1). • Centration has been excellent since the decentration force, ciliary muscle action during fibrosis, is eliminated by the use of atropine for three weeks. • The optic of plate lenses consistently locates in a position that is in the posterior part of the bag space up against the vitreous face. In many cases the posterior surface of the lens is located more posteriorly than the preoperative posterior capsule of the intact human lens.4 The more posteriorly the lens locates, the smaller can be the optical zone. • Edge glare from silicone lenses is extremely rare, since unlike PMMA lenses, the internal reflections are minimal. • There have been few complaints of reflections or edge glare from any of the more than one hundred patients implanted with a 4.5 mm optic in the clinical trials with the various accommodating lens designs with a normalsized pupil even under dim lighting. Initial Clinical Results from the Implantation of the AT-45 Lens Table 27.2 tabulates the results from the implantation of the first 21 eyes by Dr Arturo Chayet, MD in Mexico in 1999. Twenty-one eyes from thirteen patients (5 male and 8 female) were implanted with the AT-45 lens and followed for from 1 week to 10 months. The mean age was 69 years. The inclusion criteria included good visual potential, corneal cylinder of 1 diopter or less, and the presence of a cataract. The results of patients implanted bilaterally and off atropine are summarized in Table 27.2 and those implanted unilaterally in Table 27.3. There were no complications of dislocation, decentration, capsulotomy, CME, retinal detachment, or pigment deposits. At one week postoperatively there was no evidence of postoperative iritis. These preliminary results are promising; the precise mechanism of action is still somewhat theoretical and open to debate.

OD: 2/25/99 OS: 8/02/99

OD: 7/12/99 OS: 3/11/99

OD: (VS2) 7/12/99 OS: 3/25/99

OD: 2/25/99 OS: 7/12/99

OD: 2/11/99 OS: 1/28/99

MIG Age 75

MLA Age 77

JGP Age 67

MDC Age 78

SFC Age 66

20/15 20/40

20/40+ 20/40

20/80 20/15

20/15

20/25

J4/5 J2 J3 J1

20/15

20/30

20/30+2 J3 20/40 J4 J3 J1

20/20

20/20+ 20/30

J2 J1

OU 20/30

D

J1 J1

20/50 20/50

N

CL = contact lens to give plano refraction

OD: 7/12/99 OS: 5/17/99

BEI Age 60

D

J1

J1

J1

J2

J1

J1

N

40 cm

30 cm

40 cm

30 cm

40 cm

50 cm

Reading Dist

OD: Plano OS: –1.00

OD: +1.50 –1.00 × 75 OS: –0.75 –0.25 × 25

OD: (VS2) –2.00 OS: –0.25 –0.50 × 165

OD: Plano –0.25 × 60 OS: –0.75 –0.50 × 90

OD: Plano –0.50 × 112 OS: –1.00 –0.25 × 125

OD: –1.25 OS: –1.25

Ref

20/20 20/20

20/20 20/25

20/25 20/25

20/20 20/25

20/20 20/20

20/15 20/15

J3 J2

J4 J5

J1

J3 J3

J2 J3

J4 J5

BCDVA DCNVA

ACC AMP

CL* OS 2.00 20/20 J1 2.00

1.75 1.75

1.25 2.00

1.25 1.50

2.00 1.50

CLOU 2.25 20/15 J3 1.75

OU w/CL

AND

*

SX Date

Patient

Uncorrected vision

Laura Gomez, MD Shiley Eye Center, UCSD School of Medicine

Table 27.2: Examinations in Tijuana, Mexico

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Patient

Refraction

Uncorrected VA’s

BEI Age 60 SFC Age 66

OD: Plano (CL) OS: Plano (CL)* OD: Plano OS: Plano (CL)*

*

20/25 20/15 20/20 20/20

J3 at J2 at

OU 50 cm OU 40 cm

CL = contact lens to give plano refraction

*

C and C Vision has applied for FDA and Health Canada approval to conduct clinical trials in the US and Canada early in the year 2000. Meanwhile trials are being initiated in Brazil, Germany, Japan, Portugal, South Africa, Spain and the UK. REFERENCES 1. J Stuart Cumming: Postoperative complications and uncorrected acuities after implantation of plate haptic silicone and three-piece silicone intraocular lenses. J Cataract Refract Surg 19: 263-74, 1993. 2. J Stuart Cumming: Surgical complications and visual acuity results in 536 cases of plate haptic silicone lens implantation. J Cataract Refract Surg 19: 275-77, 1993. 3. J Stuart Cumming: Capsulotomy rate in silicone plate haptic and prolene-loop IOLs. Eur J Implant Ref Surg 6: 200-04, 1994. 4. J Stuart Cumming, J Alan Ritter: The measurement of vitreous cavity length and its comparison pre- and post-operatively. Eur J Implant Refract Surg 6: 261-72, 1994. 5. J Stuart Cumming: Letter to the Editor of Journal of Cataract and Refractive Surgery regarding Dr James A Davison’s letter on polypropylene silicone IOLs, 1995. 6. Joseph Colin: The Haptic Anchor Plate mini-loop foldable intraocular lens clinical results in 95 eyes. Submitted for publication in the EJCRS, 1995. 7. Presentations made by Prof Colin and Mr Condon at ESCRS Meeting in Amsterdam, 1995. 8. Jochen Kammann: Vitreous-stabilizing, single-piece, mini-loop, plate-haptic silicone intraocular lens. J Cataract Refract Surg 24: 98-106, 1998. 9. Thornton S: Lens implantation with restored accommodation. Current Canadian Ophthalmic Practice 4: 60-62, 1986. 10. Data from the AMO ARRAY FDA study. 11. FH Adler: Physiology of the Eye (4th ed): CV Mosby: St. Louis, 280, 1965. 12. Busacca, A La Physiologie Du Muscle Ciliaire Etudiee Par La Gonioscopie. Annales D’Oculistique 1-21, 1955. 13. D Jackson Coleman: Unified Model for Accommodative Mechanism. Am J Ophthalmol 69: 106379, 1970. 14. Jochen Kammann, personal communication.

Keiki R Mehta Kirit K Modi

Suprahard Cataracts: Their Evaluation and Management

28

INTRODUCTION Phacoemulsification of suprahard cataracts is a challenge. These cataracts are in a class by themselves and require special techniques to manage them. The structure of these cataracts differs from the routine mature cataracts and therefore their management. The aim for any surgeon who commences phacoemulsification is, ultimately to be able to do all cataracts routinely. One commences with softer cataracts, ultimately leading to more and more hard cataracts till one reaches, the ultimate, the suprahard cataract. At some time or the other, each surgeon reaches the watershed of the suprahard cataract. He can proceed ahead and become the complete phaco surgeon, or remain behind forever, afraid, knowing that for him the “final frontier” has not been conquered. Essentially suprahard cataracts can be differentiated into two separate types: brunescent (or hard brown) cataracts fall into one category while the whitish, marbled opalescent cataracts fall into the second category. Since the intrinsic pathology and the manner of surgically handling them, differs radically, each of these two specific types of cataracts are, to be considered separately. Brunescent Cataracts These are cataracts, which are very hard with a shiny brownish reflective surface resembling the reflection off the carapace of a beetle; hence these cataracts are also called “beetle” cataracts. Typically the color varies from aged mahogany to almost

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pitch opalescent. They consist of a thin capsule, little cortex, and three layers of nucleus—a thin epinucleus, a firmer inner nucleus and a hard amorphous central core. Equally characteristically the outer carapace is very hard and thin. It is almost as if it is a lens laminate. Two layers of hard brown carapace laminate with an amorphous non-laminated layer in the middle. Brunescent cataracts if allowed to harden a bit more, tend to inspissate, and change color to become almost opalescent cataracts (cataracta nigra). Opalescent Cataracts Opalescent cataracts are very dense cataracts with friable capsule, negligible cortex and virtually all nucleus. The central core is only marginally thicker. Typically the surface seems mottled, whitish grayish with a touch of yellow, almost like aged Italian marble. The capsule is very thin and deeply adherent to the anterior cortical surface, which makes doing a good rhexis almost an art. Often the capsular edge is hardly visible and great care needs to be exercised. The nucleus is one homogenous mass of almost equal thickness, which, unlike the brunescent cataract, is not differentiated. BASIC SURGICAL PREPARATIONS It is important when dealing with suprahard cataracts to prepare carefully. There are some fundamental requirements. Some seem obvious but then the obvious is often forgotten. In dealing with very hard cataracts, there is no margin for error. Prepare the Third Port Customarily one uses a side port for the second instrument, be it a chopper or repositor and the main 2.8 to 3.00 mm port for the phaco entry. However it is an excellent concept to prepare the third port in advance. Use a thin blade (Alcon V Lance is ideal) to make side port at 5 O’clock position. You may not need to use it but in case problems occur, the side port conveys an anterior chamber maintainer. Why the third port? Simply because one often needs to use maximal ultrasound power coupled with adequate suction to simply hold the very hard fragments and the chamber, will, often despite the best available instrumentation, fluctuate in depth endangering the endothelial cells. Though most phaco units have surge control, sometimes the quantum of surge is not possible for the instruments to contain. The chamber maintainer acts as a superb device to prevent it occurring. It is very difficult to make the port later. Be Sure of a Good Capsulorrhexis The only safety net in phacoing brunescent and opalescent cataracts is a good rhexis. A torn rhexis will fail in the number of gymnastics involved and will let the nucleus fall in the vitreous. Often there is inadequate red glow available to do the rhexis in the conventional manner. Utilize an illumination from the side (ideal is an

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endoilluminator placed just within the limbus), which will enable the capsule to be easily visualized. The author has found that the use of a Kodak written No. 60 brown filter placed in the beam of the endoilluminator works well to illuminate the capsule edges which stand out as black edges in the light. Though Healon is an ideal viscoelastic to use, iced methylcellulose is an excellent for use during the rhexis. A sharp pointed rhexis forceps, works better than a bent needle. The size of the rhexis should be at least 6 mm in size. Do a Very Cautious Hydrodissection Though it is important to do a good hydrodissection caution should however be the watchword. Brunescent and opalescent cataracts are virtually all nucleus and have little cortical buffering material. Adhesions between the nucleus and the peripheral capsule cortex complex need to be carefully hydrodissected prior trying to rotate the nucleus. While doing a hydrodissection inject the balanced salt in very small aliquots as a sudden large injection in a single area will result in a severe capsular distention, leading to a forward shift of the lens/iris diaphragm with the eye tightening up suddenly. At this stage, one proceeds with extreme caution or a posterior capsular blow-out occurs, resulting in a sunken nucleus. The ideal step at this stage when the eye suddenly becomes tight is to simply take a iris repositor and sweep it horizontally with no back pressure in all directions. Usually a small exit channel develops, the pent-up fluid escapes, the anterior chamber deepens and immediately the eye softens. Rotation of the Nucleus Brunescent and opalescent cataracts should never be spun using a two-hand technique following hydrodissection. This technique was described in an effort to rapidly release adhesions between the cortex and the nucleus. Though functional in medium and even moderately hard cataracts it should not be tried in brunescent and opalescent cataracts as it will tear the capsule or lead to a zonular dehiscence. If the lens does not rotate freely one must hydrodissect again. Do not proceed with the surgery unless you have a good free rotation. The Use of Iced Methylcellulose and Cold (+4o) C Infusion Solutions The author is not seeking to decry the various advantages of using a combination of adhesive and expansive viscoelastics as propounded by Arshinoff, which would be an ideal combination. However, one can easily utilize the very cheap alternative of hydroxypropyl methylcellulose (HPMC) if one freezes it. Freezing the methylcellulose increases the viscosity by a factor of three. It damps down the sudden movement of the chamber, keeps the chamber well formed in difficult situations, and most importantly does not ooze out quickly. Actually it is an ideal medium for use in pediatric cataracts. It stabilizes the anterior chamber so well that doing a rhexis in difficult cases is comparatively easy. Since it does not flow out easily maintaining the chamber

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depth is simple. Surprisingly, iced methylcellulose has a higher degree of adhesion to the cornea as can be seen by the little bubbles in the cellulose adhering to the cornea which stay almost till the end of the case. In addition, iced methylcellulose stabilizes the posterior capsule and damps down the explosive release of a plate haptic IOL thus enabling easier, and safer placement of the injected plate haptics without compromising the capsule. The only hassle, if it is taken as one, is the final removal of the cold methylcellulose especially if one has finished the surgery fast. Though at room temperature methylcellulose in the anterior chamber is easy to aspirate with the 0.3 mm irrigation/aspiration handpiece, iced methylcellulose, especially if the surgery has been fast, will only aspirate through a 0.4 mm, or larger, bore cannula. Thus one has to keep a separate cannula with a wider bore for this job. Keep the BSS and the methylcellulose always iced. The correct place is the first compartment below the freezer section in a regular refrigerator. Always store the methylcellulose and the BSS there. Take the BSS bottle out just prior usage. Wrap in an insulating material (thin foam plastic sheeting (3.00 mm thick), with a rubber band around it, is ideal). The use of freezing (not frozen) infusion solutions is ideal where the use of U/S energy is likely to be high. It keeps the phaco tip cooler, prevents corneal burns is said to be endothelially safer. Ancillary advantages are a quieter eye, with significantly less redness, both during and after surgery, with lesser prostaglandin response. Interestingly, patient’s done under topical anesthesia, with iced infusion solutions are much more comfortable both during and after surgery (cryoanalgesia). ANESTHESIA FOR BRUNESCENT AND OPALESCENT CATARACTS The ideal anesthesia has always been a parabulbar or sub-Tenon block. It has the advantages of a peribulbar, with none of the disadvantages. Giving the block with a curved 18 mm, tip rounded and blunt 23 G cannula with a 0.3 mm port, 2 mm behind the tip (Mehta parabulbar cannula) permits a very safe entry, with minimum risks. The block works almost immediately, though the movement of the eye may take three minutes to stabilize down. There is no need to add adrenaline in the 2 percent Xylocaine block, nor is there any need for additional hyaluronidase and a total of 1.00 to 1.5 cc suffices for an adequate block. Since the quantum of the block is small there is no need to massage or to wait till the IOP comes down. One can literally start the surgery immediately. The block works well from 15 minutes to almost 20 minutes and the biggest advantage is that it can be refilled at any stage of the procedure without the attendant risk of increasing the IOP. The author has however converted to virtually full-time surgery utilizing only simple topical anesthesia with 4% Xylocaine eyedrops. The drops are commenced one minute prior to the surgery, with a drop every 15 seconds and an additional drop is instilled just prior to checking the IOP with a Schiotz tonometer, and prior washing the eye out with the Betadine solution. Topical usually suffices, provided the surgeon is fast. Its effective time, despite all the comments by other authors,

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is restricted to about 12 minutes (based on an analysis of over 300 consecutive cases followed up with the patients told to report when the patient first commences to feel “anything”. Usually there is a 2 to 3 minute leeway before the patient starts feeling significantly uncomfortable). It is imperative that intracameral 1% Xylocard (That’s Xylocaine used for cardiac use, and has no preservatives) be kept on the table as some patients feel the distention of the globe (when the phaco tip is put in and irrigation is on the maximum height) uncomfortable. Injection of a 0.5 ml of 1% Xylocard with a 30 second wait works beautifully. It is also essential to use if a case is complicated and one doubts the length of the surgery. It must however be emphasized that unless the surgeon is skilled in phaco surgery, with a well-skilled team, topical anesthesia be best kept only for softer cataracts. It is also wise to keep an additional labeled syringe filled with Xylocaine 2% with a long curved cannula to be used as a parabulbar as standby anesthesia. It is also important when handling the case under topical anesthesia to critically assess the patient-response under the drapes prior commencing surgery. Experience has shown that the use of oxygen under the drapes, preferably via soft silicone nasal prongs is a very wise step. Not only does the whistling of the air in the nose make the patient feel that he or she is breathing plenty of air but more importantly it prevents the craving for more oxygen, important in those with any respiratory disability. Ideally the oxygen saturation monitor should be kept as a routine and saturation maintained at or above 95 percent level. Incision Placement The incision is a very important step in phaco surgery, but nowhere is it as important as when the brunescent and opalescent cataracts are considered. The quantum of ultrasound energy and the amount of intracameral maneuvers in the anterior chamber are very much greater. In addition one needs to be as far away from the dome of the cornea, not only in the center but also in the periphery. The ideal incision remains a temporal or semitemporal corneal two-step tunnel. The first groove made 150 microns deep is made at the corneoscleral limbus, just where the vessels are ending. Usually a properly placed incision will ooze a little which is ideal as it helps in early healing. The corneal tunnel is made 2.00 to 2.50 mm long from this point. Too long a tunnel makes maneuvering difficult and produces oar locking. Too short a tunnel will lead to wound leak, and will tend to stress the edges of the incision leading to a tear at the incision edges. However all corneal incisions are prone to develop a slight burn if the ultrasound energy is used too long at a high level. When in doubt, the scleral-based ‘V’-incision (also termed the Chevron incision), is the safest way to go. Sclera does not burn easily, can take a great deal of lever movement during phaco (oar movements), without damaging its sealing capacity and most important of all, worst comes to worst, can be sutured easily and covered with conjunctiva which makes it a very safe procedure.

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There is an alternative technique utilizing the free flow needles and sleeves that are now available. With these the risk of corneal burns is virtually eliminated. If available to you, the ideal incision would then be a clear corneal incision but made right at the sclerocorneal junction. Finally remember to always use iced (4oC) BSS solutions. They protect the endothelium cells and more important, severely reduce the incidence of corneal burns. In addition the cold saline acts as an excellent hemostat. Eyes operated with iced saline are virtually painless in the immediate postoperative period, very much quieter the next day, and are more comfortable. SURGICAL TECHNIQUES: BRUNESCENT AND OPALESCENT CATARACTS Essentially suprahard cataracts can be differentiated into two separate types: brunescent and opalescent cataracts. Since the intrinsic pathology and the manner of surgically handling them differs radically, each of these two specific types of cataracts are, being considered separately. Surgical Technique: Brunescent/Black Cataract Removal of a brunescent cataract is a two-step procedure. These types of brunescent cataracts cannot be split through and through by any chopping or splitting method or even by lollipoping. One can however do edge fractures, which still will not extend upto the central nucleus. Brunescent cataracts usually cannot be flipped out of the capsule into the supracapsular mode without tearing the capsule unless a very wide rhexis is made (7.5-8.0 mm). On the other hand, once flipped, they are simple and safe to handle. The posterior capsule of a brunescent cataract is loose and trampolines easily. It also rucks easily. Both can lead to a tear unless caution is exercised. There are many ways of handling this type of cataract, but the key is to open the anterior thick nuclear layer, which has the consistency of leather with tacky adhesions, to expose the central nuclear that is amorphous and can be phaco’d easily. The Deshelling Technique Another very simple technique, which I favor still more, is really effective. I call it a “deshelling technique” (Figs 28.1 to 14). Here first a single chop is made, slightly eccentric, extending from 7 to 11 O’clock. It is a superficial chop since it cannot penetrate to the center. At this point till the nucleus is de-shelled, the entire procedure is done under viscoelastics without using the phaco tip or any ultrasound. The nucleus is rotated till it is in the plane of the side port incision, i.e. the chop line now runs from 3 to 7 O’clock. Through the side port which is at 3 O’clock, pass a thin blade iris repositor, held in the left hand and the split is stabilized, Now a small blunt hook (made by bending the distal ½ mm of a thin blade iris repositor) is placed from the 3.00 mm incision and placed in the depths of the single chop and pulled to literally uncover the central hard core. A little dissection

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Fig. 28.1: Deshelling treatment—hard nucleus being impacted

Fig. 28.2: Deshelling treatment—vertical split being made for deshelling the nucleus

Fig. 28.3: Deshelling treatment—split being deepeend

Fig. 28.4: Deshelling treatment—central nucleus being shelled follows

Fig. 28.5: Deshelling treatment—central hard nucleus mass held in phaco tip

Fig. 28.6: Deshelling treatment—central mass chopped

will expose a major part of the central amorphous nucleus, which is flipped out into the anterior chamber. Thus the nucleus has been deshelled. It is now simple to handle the small nucleus piece. Use the phaco tip under high aspiration, fix it with a burst of ultrasound and proceed to chop it into little bits, use pulse phaco and remove it. The final de-shelled outer carapace is flipped over and phacoed.

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Fig. 28.7: Deshelling treatment—bimanual removal of cortical remnants

Fig. 28.8: Deshelling treatment—plate haptic looped vitreous stabilizer lens

Fig. 28.9: Deshelling treatment—lens being prepared to be gripped in holding forceps

Fig. 28.10: Deshelling treatment—forceps folding lens

Fig. 28.11: Forceps compressing lens fully

Fig. 28.12: Deshelling treatment—lens inserted in eye

The Pizza Flop Technique Make partial (pizza style) chops. Partial, since the chops do not and cannot penetrate all the way through the substance of the nucleus (Figs 28.15 to 19). The partial chops are made at 1 hour intervals all over the peripheral part of the nucleus with the splits extended until they all meet at the center. Then the center part is peeled

SUPRAHARD CATARACTS: T HEIR E VALUATION

Fig. 28.13: Deshelling treatment—anterior loop being flexed under capsular edge

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Fig. 28.14: Deshelling treatment—lens stabilized in place

Fig. 28.15: Pizza flop technique

Fig. 28.16: Pizza flop technique—initial chop from peripheral to center

Fig. 28.17: Pizza flop technique—second choopped

Fig. 28.18: Pizza flop technique—removal of hard core prior phaco

off in small triangular flaps till the center is exposed Showing the hard central core. The empty hard nuclear shell is then partially flipped or as the authors prefer to call it, flopped, out. It is then chopped as if one is doing a routine medium cataract, with a sharp chopper, and gradually using pulse phaco aspirated with only a modicum of ultrasound.

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Fig. 28.19: Pizza flop technique— splitting the hard core

Fig. 28.20: Narrow pupil impacting lens prior phaco

This will now leave the leathery outer carapace or cover. Using the Howard Fine technique, flip it over, impact it in the middle, hold with aspiration, using a sharp-sided, but blunt-tipped chopper, slice it into bits and stuff it down the phaco tip with minimal ultrasound. Be very certain to keep the bottle high as the loose, lax posterior capsule will flop back and forth (trampoline) and can get easily sucked in the phaco tip and broken. Saddle–Hump Phacoemulsification Virtually all techniques to handle the brunescent or black cataract are based on opening the nuclear hard envelope to permit phaco of the central amorphous hard crumbly mass. Often the amorphous mass can be lifted or levered off its base and then simply phacoemulsified. A new technique was thus commenced with a simple understanding. If one was to break the binding of a book the pages will automatically fall loose. The binding of a suprahard cataract is at the edges. If the edges can be systematically broken the two pieces of the carapace will fall separate to the central amorphous hard nucleus. The technique involves in first making the nucleus stand a little oblique with its edge tipped out off the bag by injecting viscoelastic under the right edge of a wellhydrodissected lens. The edge of the nucleus then flops out of the rhexis bag. The phaco tip is then impacted into the substance of the lens (Figs 28.20 to 22). A special chopper was designed, called a “humper”. It had a notched blunt tip, a flat 0.75 mm curved chopper. When it is put over the edge of the lens and pulled a small segment of the edge of the lens, like a small saddle, which is placed over the horse, is pulled off the hump of the lens. One systematically goes over the entire lens, rotating it in turn and pulling off the little bits, which come off fairly easily. The next step is to reduce the clutter in the chamber by using pulse phaco and removing all the small de-humped saddles. Ultimately, the leaves of the lens fall apart, with the hard carapace separating into two oval halves with central amorphous hard crumbly mass in the middle. Each is simple to phaco separately.

SUPRAHARD CATARACTS: T HEIR E VALUATION

Fig. 28.21: Narrow pupil splitting lens

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Fig. 28.22: Narrow pupil—vertical phacoemulsification of fragments

Phaco Settings and Surge Protection in Brunescent Cataracts The phaco machine settings are quite different when one manages a brunescent cataract. Essentially one needs to remember that the phaco tip is to be used as a holding device. To hold a hard cataract, the ultrasound energy at the beginning should be adequate to cause the tip to penetrate into the hard nuclear mass. The best phaco settings, in my hands, using an “Alcon Legacy” with its MaxVac cassettes: phaco energy at 80 percent power with a suction of 410 mm Hg and an adequate flow rate of 28 ml. Certain machines however cannot maintain chamber stability at these high levels. Typically with the alternate, standby machine the author uses, an Opticon P-4000, the typical settings are 100 percent phaco power, 120 mm Hg suction and 22 ml/min as flow rate. In brunescent and black cataracts, the periphery of the nucleus, or as I prefer to term it, the outer nuclear carapace, has to be opened up, or peeled off. The inner nuclear amorphous layer can be handled with much simpler parameters. The inner nuclear layer has a material, which is cheesy and sheds easily (like an old rubber mattress), needing very little energy. It will yield to an energy level of 40 percent or even less, ideally on pulse mode, and with a lowered suction of 180 mm Hg with the Legacy or 65 mm Hg with the Opticon with a flow rate of 18ml/min. Once the inner nuclear amorphous mass has been removed, the carapace nuclear periphery is flipped over in the “Fine” technique. This exposes the still untouched central nuclear area. The U/S energy now needs to be increased to 70 percent with a suction of 220 (Legacy) or 80 mm Hg Opticon. The carapace is impacted and sliced with a sharp chopper in vertical slices and then gradually aspirated. The reason why the suction at this point is kept so low with the Opticon unit is because the cortex in a brunescent cataract is virtually negligible thus the carapace sits almost directly on the posterior capsule which usually in these cases is loose and will trampoline forwards easily. If the level of suction is kept high, as the occlusion breaks the suction is suddenly released, and the chamber destabilizes for a few moments. The Alcon Legacy can compensate easily (The MaxVac (maximum vacuum) cassettes work like a dream). However with the Opticon as it is with many of the more economical models, the chamber destabilized. In these fractions of a second,

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the posterior capsule will trampoline and get caught, promptly breaking it. With the fluid running at a high volume and pressure, vitreous is immediately disturbed unless the surgeon anticipates the possibility of this complication developing and responds immediately. Regrettably most posterior capsules in a brunescent cataract are broken in the final stage of removal of the cataract. A very useful aid at this point to maintain chamber stability is the use of the double bottles (the Bangkok method) connected with wide bore inflexible infusion tubing. The ideal tubing is that made for prostatic transurethral resection, used by urosurgeons known popularly as a “TUR tubing”, which is freely available in India (also termed the Mehta /TUR system). This technique significantly reduces surge problems and maintains a stable chamber even in stop/ go situations even in machines with no surge control. Once the entire cataract has been chopped into little bits, unlike a soft or a medium cataract, high levels of suction are not required and thus conversely neither does the inflow pressure (bottle height) need to be high. The central amorphous material is friable and does not need high suction. If suction is low the incidence of a capsular break diminishes significantly. Do remember in the end with the fragments small to use only slow-pulsed ultrasonic energy system. It actually achieves more, faster and with greater safety. And finally when everything has gone well and the surgeon reaches the stage of simple irrigation/aspiration he or she relaxes thinking that the difficult part is over. He or she forgets that the posterior capsule, (in very hard cataracts, loose and lax) will be aspirated into the port of the I/A easily and get torn if undetected. Extreme care should also be taken when polishing these capsules which will often look far “dirtier” than the regular capsules simply because the brunescent cataract when it is hydro-dissected off the capsule leaves very fine fragments behind. The ideal way to polish is to use the Low Vac port of the phaco but alternatively a ring polisher may be used. The posterior capsule rucks easily and will tear, hence do all polishing after a good viscoelastic is filled in the anterior chamber fully to stretch the capsule and prevent rucking, which will lead to a capsular tear. Surgical Technique: Opalescent Cataracts The technique for these types of cataract is quite different. The reason is that these cataracts are virtually solid nucleus with no differentiation. Using a chopper in these full thickness lenses usually does not work. Tangential Chopping Technique The technique of tangential chopping is that rather than trying to split a lens down the middle, one goes to the periphery and left or chops off shards of nuclear tissue. With each chop, applied subsequently over another tangential chop, the nuclear burden progressively decreases. Here we are simply chopping a lens with multiple horizontal chops rather than a single, more risky, vertical chop. The horizontal chop is made slightly oblique, i.e. at a tangent and hence the term tangential chopping.

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Fig. 28.23: White opalescent cataract

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Fig. 28.24: White opalescent cataract—lens turned vertically in preparation for chopping

The thin tangential chopped nuclear remnants are like thin shards and can be phacoed very easily. Alternatively, one chops superficially and then manually increases the cleavage till it becomes or achieves full thickness. It is essential to remember that immediately behind the nucleus is a fragile, very thin capsule, which gives way at the slightest provocation. Fig. 28.25: White opalescent cataract—lens chopped

Vertical ‘Hubbing’ Phacoemulsification The authors had recently commenced a new technique termed as Vertical ‘Hubbing’ Phacoemulsification (Mehta ‘97). After a good hydrodissection and making sure that the lens rotates freely, viscoelastic is injected at the right edge of the lens, which makes the left edge of the lens stand out from the bag vertically (termed as the “Lens Salute”) (Figs 28.23 to 25). The phaco settings are changed. Minimum vacuum is used with ultrasound power set at 85 percent and aspiration set at minimum. The lens is first tilted semivertical, and supported from the left side by a blunt chopper. The phaco tip is now allowed with ultrasound to bore a hole in the middle of the lens. Since the aspiration and vacuum is minimum, the tip will not remain impacted but come out immediately. In a similar mode, three more bore holes are made, at the sides of the original bore. Thus the center of the lens is cored out or “hubbed” out. Finally after the center is ‘hubbed’ out, all that is left is the periphery of the lens, which is then snapped open, and the residual lenticular rim is simply aspirated with high suction, very minimal phaco power and carrouseled out. It is a very safe technique, and gives good reproducible results. Only requirements of this technique is a soft eye, with an adequate deep chamber. It gives the highest safety for the posterior capsule as it is held away by the periphery of the lens.

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The Use of Foldable Lenses and Injectors Foldable lenses are ideal as they permit the insertion of the IOL with none or very little enlargement of the incision. If one is not using an injector, (Unfolder, Allergan) it is important to slightly enlarge the cornea ( typically the 6.00 mm AcrySof IOL’s require a 4.1 mm opening, though the newer 5.5 mm AcrySof can be passed via 3.25 mm opening easily). Always make the opening a little larger rather than trying to force the lenses via a smaller incision as the force leads to shearing of the cornea which is uncontrolled and often leads to unstable astigmatism. This is important since a fair amount of gymnastics have been done in the chamber for removal of these cataracts which invariably leads to stress on the corneal tunnel. Preference should be always to do a controlled incision rather than force the implant in which leads to an uncontrolled corneal shear. The injectable lenses (the author’s preference is an Allergan SI 40 lens) comfortably go through a 2.8 mm opening using the newer injectors. Two steps at this point of insertion are important. Since the capsule in suprahard cataract is thin and friable do not do any manipulations on its surface. Be particularly careful when rotating the IOL in the bag. Use copious viscoelastic. In using the Chiron plate haptic IOL’s do not try and manipulate plate haptic lenses to change their position once placed in the bag, as the posterior capsule will ruck and tear. Especially for plate haptic, the use of iced methylcellulose damps down the expulsion force. Do not release close to the posterior capsule. Use delicacy in placing lens in the bag. Any force leads to a lost lens. Finally a sobering thought. Injectable lenses, especially plate haptics silicones, injected in capsules with doubtful integrity may disappear in the vitreous in a jiffy. When in doubt use looped haptics. As a personal preference, when in trouble, the Allergan loop haptics of the SL30 (prolene-based loops) are especially forgiving. Hema ( Storz Hydroview lenses), too seem to work well in these dangerous situations. For the surgeon who is commencing and who wishes to go slowly he or she may consider the possibility of utilizing the Hema Endothelial Hood as a safety net. Here a specially-designed Hema contact lens of diameter, 8.5 to 9.00 mm which is inserted intra-camerally, after doing capsulorrhexis. It is placed and stays in intimate contact with the endothelium during the phacoemulsification procedure and is then removed at the end of the procedure. It is especially useful in hard cataracts with an endothelially compromised cornea {(e.g. Fuchs’) (Mehta 95’, 97’, 99’)}. CONCLUSION Though suprahard cataracts have always been thought a problem, a proper analysis and a well-thought-out game plan will make the procedure simple to carry out with a high level of proficiency and reproducibility. No other procedure will be as rewarding, and soul-satisfying to the surgeon, with the utmost patient satisfaction, as a really beautifully phacoed difficult suprahard cataract.

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FURTHER READING 1. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989. 2. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in Paediatric Cataracts. All India Ophthl Soc Proc 207-10,1995. 3. Mehta KR: The new clover leaf stabiliser (CLS) for the safe and effective insertion of posterior chamber IOL over a broken capsular face. All India Ophthl Soc Proc 251-53,1995. 4. Mehta KR: An advanced but simple keratometer for control of postoperative stigmatism. All India Ophthl Soc Proc 122-23, 1990. 5. Mehta KR: Shelve and shear phacoemulsification. All India Ophthl Soc Proc (Mumbai), 1995. 6. Mehta KR: Phaco-levitation: a peaceful way. All India Ophthl Soc Proc (Chandigarh), 1996. 7. Mehta KR: The prephaco split technique using the contrasplit forceps–a new technique. All India Ophthl Soc Proc, 1998. 8. Mehta KR: The tripod posterior chamber flexible acrylic implant—the answer to better stability.APIIA Conference, 1997. 9. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997. 10. Mehta KR: Astigmatic control using the new curved laminating keratotomy technique. APIIA Conference, 1997. 11. Mehta KR: The tripod posterior chamber foldable acrylic lens. Proc of SAARC Conference, Nepal, 1994. 12. Mehta KR: Phacoemulsification, the “roller-flip” way for suprahard cataracts—it works great. Proc of SAARC Conference, Nepal, 1994. 13. Mehta KR: Intralenticular phacoemulsification—a new technique. Proc of SAARC Conference, Nepal, 1994. 14. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 15. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 16. Mehta KR: Effective endothelial cell protection during phacoemulsification with Hema intracameral contact lens (HICL). Proc of SAARC Conference, Nepal, 1994. 17. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

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Luther L Fry

Stretch Pupilloplasty for Small Pupil Management in Cataract Surgery

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INTRODUCTION In this chapter the author describes a pupil stretching technique which he has been used since 1992. It is simple, very effective, and requires only two inexpensive instruments, which are probably already in your set. It involves stretching the pupil, limbus to limbus, with two Kuglein hooks (Figs 29.1 to 4).

Fig. 29.1: Unstretched pupil

After stretching, the pupil is expanded with viscoelastic. A “heavy” viscoelastic such as Healon GV, works best (Figs 29.5 to 7).

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Fig. 29.2: Beginning of stretch

Fig. 29.3: Midstretch

This gives a pupil of adequate size for easy capsulorrhexis and subsequent cataract surgery in nearly all cases. In general, the smaller the pupil, the better the effect. The author does have a set of Grieshaber iris retractors available, but have not had to cut the iris or use iris retractors in a single case since using this technique. Technical Tips and Caveats • With small fibrotic pupils, there may be a tendency to develop iris tears. These are usually small and multiple. Stretching slowly (approximately 3 seconds) may help lessen the severity of these tears. The author has yet had an iris

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Fig. 29.4: Fully stretched

Fig. 29.5: Start of expansion with viscoelastic

tear large enough to cause problems and has not had significant iris bleeding. Hold for a second or so at maximum stretch. • Be sure to stretch fully out to the limbus in both directions to get maximal effect. Only one stretch is necessary. Additional stretches give little additional benefit. (the author used to go in through the side port and stretch again 90 degrees away, but stopped this when it seemed to give little additional effect (Figs 29.8 to 12). These additional stretches also seem to make the iris more “floppy” and likely to catch in the phaco tip). • The pupil may remain permanently larger, particularly in small fibrotic pupils with iris atrophy. These tend to develop iris tears. These tears are rarely large, and may really be somewhat of a benefit, especially in glaucoma cases, in

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Fig. 29.6: Fully expanded

Fig. 29.7: One day postoperation

allowing postoperative fundus view (in some of these cases, the author has not seen the optic nerve well in years). • Because of this larger pupil, particularly if there are noticeable sphincter tears, a 6.0 mm or larger optic should be used (the author prefers 7.0 mm); 5.0 mm or 5.5 mm might risk incomplete pupillary coverage. • It is easy to concentrate on only the distal Kuglein hook and forget the proximal, allowing this proximal hook to be retracted out of the wound, drawing iris with it. If one keeps this in mind, it is unlikely to happen. In the cases where this has happened to me, it has not caused serious iris damage. This procedure is simple enough to do just from this brief description; however, as with most surgical maneuvers, it is best seen on videotape and is on the accompanying videodisk.

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Fig. 29.8: Atrophic iris

Fig. 29.9: Stretch with sphincter tear

After pupil stretch, cataract surgery proceeds as per one’s usual technique. The author prefers using phaco, however, this procedure gives adequate pupillary size for a large capsulorrhexis to allow planned extra also. The author likes to groove and crack the nucleus, particularly in the small pupil cases, as he is uncomfortable with loosing visualization of the chopper beneath the iris periphery. Grooving the nucleus deeply just in the center portion allows an easy crack in nearly all cases if grooving is carried deep enough. The peripheral nucleus does not have to be grooved. The two halves are then rotated 90 degrees. The phaco tip is embedded in the distal half to hold it and it is divided again in two or more pieces depending on nucleus density. The second half is then rotated and cracked in a similar manner. This is done under low flow and vacuum. Then, with high flow and vacuum, these cracked fragments are aspirated and emulsified (Figs 29.12 to 15).

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Fig. 29.10: After expansion with viscoelastic

Fig. 29.11: One day postoperation

Irrigation-aspiration (I-A) is done by one’s preferred technique. The author prefers to use the automated I-A and then split irrigation and aspiration to go in through the side port for subincisional cortex. The foldable (or non-foldable) lens of one’s choice is then inserted (Fig. 29.16). The author has used this technique since 1992, and stretch approximately 10% of his pupils—this would extrapolate out to be something over 700 cases in which The author has used it. Any surgical procedure, of course, has some complication risk, but the author has yet to encounter his first significant complication resulting from this pupil stretching technique.

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Fig. 29.12: Groove

Fig. 29.13: Crack

Fig. 29.14: Embed and crack

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Fig. 29.15: Aspirate and emulsify on high vacuum

Fig. 29.16: A cannula is inserted through the side port for subincisional cortex

He would like to recommend this procedure for those of the ophthalmologists who have not used it. The author thinks they will find it very safe and effective. “Try it; you’ll like it”.

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Gowri J Murthy KR Murthy

Management of Glaucoma in Cataract Patients

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Cataract and glaucoma constitute two common causes of decreased vision. When they occur together, they present a unique problem in diagnosis and management. Diagnosis of Glaucoma in the Presence of Cataracts Diagnosis of glaucoma has traditionally rested on three criteria, namely the intraocular pressure (IOP), optic disc changes, and thirdly, visual field abnormalities. The presence of a cataract makes evaluation of the optic disc difficult, and poses certain problems in the interpretation of visual fields. In the presence of cataract, one can try to visualize the optic by the noncontact high convex lenses, namely the 78D, 90D, 60D, etc, on slit-lamp examination. Having a well-dilated pupil facilitates visualization through a clear area in the lens. In very advanced lens opacities, one can also try to assess the disc by indirect ophthalmoscopy, but generally, if the disc is seen by indirect ophthalmoscope, it must also be amendable to evaluation by the noncontact slit-lamp methods. Considering the stereopsis, and the higher magnification provided by the slit lamp, this method, is by and large, the preferred method of evaluation of the optic disc, especially so in the presence of cataractous lenses. Evaluation of the disc in the other eye can also provide valuable information, particularly, if a mature cataract precludes visualization of the disc in the cataractous eye. Previous disc photographs, and ophthalmic records of the patient can also provide useful information.

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Visual Fields in the Presence of Cataract Problems in Performing the Test Patients with cataracts should have the appropriate optical correction, while performing the fields. One should make a careful note of the location of the lens opacities, and try to correlate the field changes, in consideration of this. Pupillary diameter should be adequate, and any miotic used, should be withdrawn prior to the field test. Interpretation Generalized field depression can be a feature of cataracts. One should pay more attention to the pattern diviation, rather than the total deviation, as cataracts may cause the latter. In visual field examination, decreased thresholds, flattening of the central field profile, exaggeration of pre-existing scotoma, and/or constriction of the visual field, may give an erroneous impression that the glaucomatous defects have progressed.1 When the lens opacities are so dense that meaningful interpretation of visual fields is impossible, one will have to rely on the fields of the other eye, or on previous records of the patient. Gonioscopy can be misinterpreted in patients with cataract. Large or swollen lenses can alter the angle appearance, making it seem narrower than it actually is. The use of different diagnosis lenses—Zeiss, and the Goldmann lenses, in conjunction, may help in overcoming this problem. Comparing the angle of the other eye can also provide clues, as to the extent to which the lens has altered the angle appearance.2 Management of Cataract with Coexisting Glaucoma Preoperative Considerations One should meticulously work up the patient, and come to a conclusion as to the mechanism of the coexisting glaucoma, as mentioned in Figure 30.1. Management should be individualized depending on the mechanism of glaucoma. The physician should determine the relative contribution of the two conditions, the lens opacity and the glaucomatous damage to the vision loss, and he/she should explain this clearly to the patient. This will result in realistic expectations about the postoperative vision by the patient. One can also employ laser interferometry, potential acuity meters, etc. to help in predicting the postoperative vision.2 Classification • • • • •

Based on the type of glaucoma Open-angle glaucoma (OAG) with cataract Narrow-angle glaucoma (NAG) with cataract Congenital galucoma with cataract Syndromes with coexistent cataract and glaucoma.

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Open angle

Narrow angle

Hypermature cataract?

Immature cataract

Pupil block

Synechial angle closure

Phacolytic glaucoma — Neovascular glaucoma — Chronic iridocyclitis Ocular hypertension

POAG

Look for ?secondary glaucoma? — — — — — —

Signs of uveitis Neovascularization Angle recession Pseudoexfoliation Pigment dispersion Fuch’s heterochromic cyclitis — Tumors — ?Steroid induced

Mechanism of block

Special situation Malignant glaucoma

— Anatomically narrow angle with increasing lens thickness —Phacomorphic glaucoma —Subluxated lens — Nanophthalmos

Fig. 30.1: Patient with cataract with high IOP

The secondary glaucomas mentioned in Figure 30.1 should be managed appropriately, before undertaking cataract surgery. Certain situations deserve special mention. • One should be especially careful in patients with pseudoexfoliation to look for associated zonular weakness. Pupillary dilatation may also be suboptimal. • Presence of neovascularization due to proliferative diabetic retinopathy warrants panretinal laser photocoagulation, which might be done by indirect ophthalmoscopic delivery at the time of surgery, immediately after cataract extraction. • Patients with fuch’s heterochromic cyclitis are especially prone to develop, postoperative hyphema, due to the fine neovascularization that is associated with this condition. • Subluxated lenses have to be managed as the individual case dictates by either pars plana approach or limbal approach, and combined with an anterior vitrectomy in case of vitreous in the anterior chamber (AC). • Patients, who have been on chronic miotic therapy for glaucoma, will present pupillary dilatation problems at the time of surgery. Pupillary stretch techniques may have to be used in such cases. • There exists an increased possibility of occurrence of expulsive choroidal hemorrhage in patients whose IOPs have been on the higher side preoperatively, especially when there is sudden reduction of IOP at the time of entry into the eye.

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• In patients with nanophthalmos, one will have to consider performing partial thickness scleral resection in four quadrants, (vortex vein decompression), in conjunction or before the other surgical procedures.3 Management of Cataract in Presence of Glaucoma • Without prior glaucoma surgery • In the presence of a filtering bleb Options • Only glaucoma surgery • Only cataract surgery • Combined surgery—glaucoma and cataract 1. Extracapsular cataract extraction (ECCE) + IOL + Trab 2. Phaco-trab • Single site • Two sites How to Decide (Fig. 30.2) Cataract surgery indicated Well-controlled IOP mid-moderate disc, and v.f. damage

advanced disc and v.f damage

Borderline IOP mild disc and v.f. damage

Cataract extrn alone

moderate to advanced disc and v.f

Uncontrolled IOP urgent need to restore vn/ 2-stage not feasible

Two-stage procedure

Combined Procedure

Fig. 30.2: Algorithm for one approach to selecting a surgical procedure for patients with coexisting glaucoma, and cataract (from Shields MB: Ophthalmology 93: 366, 1986)

MANAGEMENT OF (WITHOUT PRIOR

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Filtration Surgery Alone, Followed by Possible Cataract Extraction Later This two-stage approach can be considered in two situations.

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In a Glaucoma Patient with Minimal Lens Opacities This approach is justified only if the lens opacities are very minimal, and the patient has adequate vision for his/her needs. Though the newer microsurgical methods of glaucoma filtering surgeries have a reasonably high success rate— 8 to 90 percent, there have been reports of significantly higher incidence of development of lens opacities following glaucoma filtering surgeries. Another consideration is that over 50 percent of these filters will be lost when a subsequent cataract extraction is performed. 1 But, with the advent of clear corneal phacoemulsification, this aspect should be reconsidered. In patients with Uncontrolled Glaucoma In the presence of uncontrolled glaucoma, despite maximal medical therapy, the urgency is to prevent further damage by IOP rise. The priority therefore is to reduce the IOP. It has been observed, that filtering surgery alone, followed by cataract extraction later, is associated with better long-term control of IOP compared to combined procedures at the same sitting. This is particularly so due to the availability of newer small incision cataract surgeries, which enable cataract extraction, with IOL implantation to be performed, at a site such that minimum manipulation or damage to the glaucoma filter occurs.5 However, with the advent of antimetabolite usage and other newer techniques of combined surgery, the observation noted above may no longer hold true. This has to be clarified by long-term studies. Cataract Extraction Alone As mentioned in Figure 30.2, this can be performed in patients with well-controlled glaucoma, on low-dose of medications, with mild to moderate glaucomatous field loss. Small incision cataract surgery has an advantage of improved chances of successful filtering surgeries to be performed later, as an untouched quadrant of superior conjunctiva is preserved.6 Combined Cataract Extraction and Glaucoma Surgery This approach can be considered in patients in whom cataract surgery is indicated, and have borderline IOP control, or patients who are not tolerating their antiglaucoma medications. Patients with well-controlled glaucoma, on medications with moderate to advanced field loss can also be considered for this combined approach. The major advantage of combined procedures is in preventing the early postoperative pressure spikes, which can cause further field loss in a glaucomatous eye.6 Also, with the use of antimetabolities, and the newer small incision cataract surgeries combined with the glaucoma surgery, better success rates have been proposed in IOP control compared to earlier methods. Generally the use of anterior chamber IOLs should be avoided in presence of glaucoma.

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ECCE + IOL + Trabeculectomy This is a well-known procedure in which the scleral (partial thickness) flap is performed, as usual, along with excision of the internal block, and performing the capsulotomy through this internal block/separate paracentesis. The wound is enlarged on either side of the scleral flap. The lens is expressed, cortical matter washed, and wound closed by continuous/interrupted sutures, after an iridectomy. Meticulous closure of the conjunctival flap is performed, which is usually fornix based in such cases. PHACO-Trabeculectomy Spaeth and Sivalingam, were the first to propose modification of the shelved posterior lip of a cataract incision to allow filtration, in 1976. With the advent of phacoemulsification, there has been resurgence of this concept. The conjunctival flap can be either fornix/limbal based. One can either make a standard trabeculectomy 5 mm partial thickness scleral flap first, and phacoemulsification, and IOL insertion is performed, in what will be the site of the sclerectomy. The sclerectomy can then be completed, and the wound closed as in any trabeculectomy, after a peripheral iridectomy. Another approach is to perform a standard scleral tunnel phacoemulsification with IOL implantation, and, later modify the posterior lip of the wound, by excising a portion of this. This causes the wound to lose its self-sealing capability, and sutures may have to be used.7 Alternately, a two-site approach can also be used. Small incision cataract extraction with IOL implantation is performed by a 3 or 5 mm wound, which can be a scleral tunnel/clear corneal. At the same time, a separate trabeculectomy is performed at a different site superiorly.7 All the three approaches, have been claimed to produce better success rates, as compared to standard ECCE-Trabs, but long-term follow-up results are still awaited. Antimetabolities can be used as adjuncts in these procedures. The guidelines for the use of these drugs, (5-FU, and Mitomycin-C) are as proposed by the Moorfields Eye Hospital/University of Florida (more flow) regimen.8 Management of Cataracts with a Pre-existing Glaucoma Filter In the presence of a filtering bleb, while performing cataract extraction one has to avoid any damage to the bleb site. Small incision or clear corneal approaches are well suited in these circumstances.5 In all the surgical procedures mentioned above, postoperatively one should particularly look for and treat postoperative pressure spikes. In the lens induced, phacolytic, and phacomorphic glaucomas, one can perform cataract extraction, by extracapsular methods, along with IOL implantation, after bringing down the pressure by medical means. Lens extraction alone, is sufficient to bring down the IOP in majority of the cases. However, in some cases, where the duration of the glaucoma has been long, one can consider combining the lens extraction, with a trabeculectomy.9

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In conclusion, the management approach in a patient with both cataract, and glaucoma, has to be decided, after careful preoperative work-up, and has to be individualized to the particular patient. REFERENCES 1. Kolker AE, Hetherington J: Becker-Shaffer’s Diagnosis and Therapy of Glaucomas (4th ed) CV Mosby: St Louis, 1976. 2. William E Layden: Cataract in claucoma. In Tasman W, Jeager EA (Eds): Duane’s Clinical Ophthalmology Lippincott-Raven: Philadelphia, 1997. 3. A. Neelakantan et al: Familial nanophthalmos—management and complication. Indian J Ophthalmol 42(3):139-43, 1994. 4. Laakainen L: Late results of surgery on eyes with primary glaucoma and cataract. Acta Ophthalmol 49: 281, 1971. 5. HJ Park, YH Kwon et al: Temporal corneal phacoemulsification in patients with filtered glaucoma. Arch Ophthalmol 115:1375-80, 1997. 6. LF Cashwell, MB Shields: Surgical management of coexistent cataract and glaucoma. In Ritch R, Shields MB, Krupin T (Eds): The Glaucomas (2nd ed) CV Mosby: St Louis, 1745-61, 1996. 7. Allen D: Combined procedures. In Yanoff M, Duker J (Eds): Ophthalmology, CV Mosby: St. Louis, 4:27-32, 1999. 8. Peng T Khaw, Mark Wilkins: Antifibrotic agents in glaucoma surgery. In Yanoff M, Duker J (Eds) Ophthalmology CV Mosby: St. Louis, 3: 12-31, 1999. 9. Braganza A, Thomas R, George T et al: Management of phacolytic glaucoma—an experience of 135 cases. Indian J Ophthalmol 46:139-43, 1998.

Garry P Condon Luis W Lu

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INTRODUCTION Advances in small incision clear corneal phacoemulsification and folding intraocular lens (IOL) technology have had no greater an impact in the management of cataract than in the glaucoma patient. Reduced incision size with a folding IOL improves the likelihood of continued bleb function in the filtered eye.1 A clear corneal incision that completely avoids conjunctival manipulation in the glaucomatous eye, allows infinite variability in the timing of a filtering procedure whenever surgical control of intraocular pressure (IOP) is necessary following cataract surgery (Fig. 31.1). In the previously filtered eye, the remaining available undisturbed conjunctiva greatly facilitates any repeat filtration procedure when needed (Fig. 31.2). Phacoemulsification in the glaucomatous eye with a preexisting bleb, though generally safe, involves potential pitfalls not encountered in the otherwise normal eye.2 The most well recognized and concerning of these is the prospect of bleb failure requiring additional glaucoma surgery. A recent study suggested a bleb failure rate after phacoemulsification of approximately 5%, in patients with mean follow-up of 18 months.3 Additional studies have demonstrated fewer filtering bleb failures after uncomplicated phacoemulsification compared to extracapsular cataract extraction (ECCE).4,5 In the absence of complete bleb failure, an IOP rise of 3 to 6 mm Hg on average, has been reported, with no statistically significant difference attributable to antimetabolite use at the time of filtering surgery.6,7 Currently, there are no studies demonstrating increased bleb survival or IOP control associated with the use of 5-FU injections following cataract surgery in the presence of an established filtering bleb. Though not statistically significant, trabeculectomies originally performed with adjunctive mitomycin-c,

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Fig. 31.1: Phacoemulsification through a clear corneal incision

Fig. 31.2: Cataract surgery in a previously filtered eye

compared to those without, tend to have better survival rates following phacoemulsification.7 Factors associated with early or late bleb compromise following phacoemulsification include intraoperative iris manipulation, an early postoperative pressure spike, preoperative IOP of greater than 10 mm Hg, and young patient age.3 Additionally, a time span of less than six months between trabeculectomy and cataract surgery as well as preexisting uveitis predisposing to exaggerated postoperative inflammation are variables that have been associated with loss of IOP control.8 Deferring cataract surgery for greater than six months after the original filtering procedure may allow the bleb sufficient time to become wellestablished and reduce the failure rate.9,10 Intraoperative iris manipulation can adversely influence bleb function in the short-term, as well as the long-term. The acute formation of fibrin may obstruct the internal sclerostomy, resulting in a dramatic pressure spike occurring within days of the surgery. Long-term postoperative inflammation due to blood-aqueous barrier breakdown is a probable cause for late bleb compromise.11 The number of patients requiring iris manipulation at the time of cataract surgery, though recently reported to be close to 50%, should fortunately lessen with the decline in chronic miotic therapy.3 Intracameral tissue plasminogen activator (tPA) may play a valuable role in the management of an acute postoperative IOP spike associated with an early anterior chamber fibrinoid reaction.12,13 Other theoretical causes of early postoperative pressure spikes include retained viscoelastic material, or lens particles that may be forced into the bleb by way of the internal sclerostomy during emulsification. The authors also postulate continued accessibility of lens epithelial cells to the filtering bleb immediately following capsulorrhexis. These cells most frequently undergo fibrous metaplasia

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once disturbed, and as a result, may enhance the likelihood of bleb fibrosis.14 The presence of viscoelastic material, lens particles, and liberated lens epithelial cells are variables that are not present in patients simply undergoing trabeculectomy alone and might possibly contribute to bleb failure in the previously filtered eye as well as a lower success rate in combined phacotrabeculectomy surgery.15-17 Surgica l Approaches Essential to selecting an appropriate surgical approach is the complete evaluation of the patient’s optic nerve and visual field status, along with all information pertaining to the patient’s glaucoma medication history. A suggestion of progressive glaucomatous visual field progression would indicate some form of filtration augmentation be undertaken at the time of cataract surgery. A clear picture of the patient’s medication tolerance, compliance, and response, is of utmost importance in anticipating the ability to control postoperative pressure elevation and thereby adjust the surgical approach accordingly. Although cataract surgery in the presence of a filtering bleb always creates a real possibility of bleb compromise, the option of combining simultaneous bleb revision affords an opportunity to enhance filtration and potentially long-term pressure control. Previously filtered patients undergoing cataract surgery generally fall into one of three categories. First, there are the patients with apparently well functioning filtering blebs, in whom simple clear corneal small incision phacoemulsification is preferred along with the meticulous medical management of postoperative inflammation, and potential early IOP spikes. With this approach, care must be taken to avoid manipulating the conjunctiva and iris if at all possible. A second category includes patients with marginal bleb function, or blebs that appear doomed to further compromise following phacoemulsification. In these patients, an internal bleb revision technique, utilizing a spatula directed through the internal sclerostomy via the corneal incision may improve filtration or provide some protection to the bleb. 18 Conversely or concurrently, minimal external dissection can be used to release fibrous adhesions allowing expansion of the bleb and enhanced outflow.19 Postoperative 5-FU injections or intraoperative mitomycin-C in the case of an external dissection may be considered. The remaining patients are those in whom an obvious pattern of preexisting complete bleb failure requires combining cataract surgery with either complete revision of the original filtering bleb utilizing extensive conjunctival dissection, or the creation of an entirely new filtration site adjacent to the previous one. Combined phacoemulsification and trabeculectomy utilizing two separate sites has made this latter approach much more feasible where space constraints are not nearly the problem they were prior to small incision clear corneal phacoemulsification.20 The selection of a surgical approach is influenced ultimately by the desired target IOP for that individual patient, while considering available reserve options which might be required for postoperative pressure control. A 45-year-old patient with split fixation, a pressure of 15 mm Hg and poor medication compliance

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should be considered for internal bleb revision at the time of cataract surgery. Alternatively, a patient with uncontrolled glaucoma in the presence of a bleb that has never demonstrated established function requires consideration be given to combining phacoemulsification with a second trabeculectomy and adjunctive mitomycin-C. Depending on the urgency of visual rehabilitation, proceeding with a second filtration procedure without concurrent cataract surgery might be most appropriate. Preoperative Considerations While fortunately used less frequently, it is essential that miotics be discontinued preoperatively and if necessary, replaced temporarily with another topical agent or an oral carbonic anhydrase inhibitor. Currently, the indications for discontinuing the topical prostaglandin agents preoperatively are controversial.21 It is reasonable to consider initiating topical corticosteroid therapy a few days prior to surgery in an attempt to suppress any immediate postoperative inflammation. This can be combined with concurrent topical antibiotic therapy in the same period. We routinely recommend preoperative topical non-steroidal therapy in diabetic patients and those more prone to cystoid macular edema (CME).22, 23 Preoperative IOPs of less than 10 mm Hg in filtered eyes, are increasingly common as a result of the widespread use of antifibrotic agents with filtration surgery. Biometry and IOL power calculations are frequently less accurate in these marginally hypotonous eyes. A falsely short axial length measurement with the ultrasound probe can easily occur. The refractive error prior to the original trabeculectomy, as well as biometry of the fellow eye, should be evaluated in selecting an appropriate IOL power. In our experience, though not predictable, previously hypotonous eyes may have enough of an IOP increase following cataract surgery to result in a postoperative axial length increase and an apparent IOL power miscalculation. There is no simple IOL power algorithm in cases of hypotony. The operating surgeon is ultimately responsible for evaluating all biometric data to best select the most appropriate IOL power. Preoperative evaluation of maximal pupillary dilation, as well as the presence or absence of pseudoexfoliation, will help in alerting the surgeon to a potentially more challenging and complicated procedure. Gonioscopic evaluation of the internal sclerostomy for location and patency is essential if internal revision of the bleb is planned. We recommend avoiding external ocular compression devices like the Honan balloon immediately prior to surgery to avoid excessive hypotony or the possibility of bleb trauma. Moreover, the scrub technician must maintain a delicate approach to the preparation of the operative site. Special Considerations during Cataract Surgery Phacoemulsification in the presence of a preexisting filtering bleb is different in several respects from cataract surgery in an otherwise normal eye. First, every effort must to be made to avoid traumatizing the bleb, which nowadays can

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Fig. 31.3: Kershner eyelid speculum provides excellent exposure

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Fig. 31.4: Incision 90 degrees away from filtering bleb

be markedly thin and prone to rupture with something as simple as contact with a cellulose sponge. The lid speculum should be placed gently in the adjacent fornix after adequate irrigation, to reduce bleb trauma. A Kershner speculum (Rhein Medical) provides excellent exposure with minimal trauma under topical anesthesia (Fig. 31.3). Supplemental intracameral preservative-free lidocaine, allows complete pain free iris manipulation. The authors recommend a true clear corneal incision that totally avoids incising the conjunctiva. Placing the incision at least 90 degrees away from the bleb reduces the likelihood of direct trauma (Fig. 31.4). An incision that is directly anterior to a filtering bleb, increases corneal striae hampering visualization, delays wound healing, and increases the possibility of endothelial cell loss associated with a more central incision.24,25 Entering at the insertion of the conjunctiva or slightly posterior, can cause subconjunctival hemorrhage capable of extending into a preexisting diffuse bleb. Excessive Tenon’s hydration with ballooning of the conjunctiva may also occur and compromise visualization (Figs 31.5 to 7). A paracentesis for a second instrument must be far enough from the filtering bleb to avoid trauma during the surgery. The careful handling of sharp instruments, particularly diamond blades, cannot be overemphasized as an inadvertent superficial bleb laceration may create a problematic surgical procedure with an unstable anterior chamber, as well as disastrous long-term leakage in a patient with a thin avascular bleb. Similarly, scleral fixation devices should be avoided in these patients. Deepening of the anterior chamber with a highly retentive viscoelastic agent, affords a well-controlled capsulorrhexis, and possibly temporary protection of the sclerostomy site from particulate lens matter during the emulsification. Care should be taken not to overinflate the anterior chamber forcing excessive viscoelastic into the bleb. The capsulorrhexis should be large enough (5-5.5 mm) to allow manipulation of lenticular fragments at the iris plane and avoid late capsular phimosis due to inadequate overall diameter (Figs 31.8 and 9). The requisite

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Fig. 31.5: Entering at the insertion of the conjunctiva

Fig. 31.7: Hydration and ballooning of the conjunctiva

Fig. 31.6: Incision just posterior to the insertion of the conjunctiva

Fig. 31.8: Capsular phymosis

liberation of anterior capsular debris with YAG laser photodisruption to treat any phimosis may potentially compromise bleb function and is preferably avoided. Reduced pupillary diameter is generally the limiting factor in achieving an adequate anterior capsular opening. It is at this point that the surgeon must weigh the potential advantages of pupillary enlargement against the disadvantages of iris manipulation that is strongly associated with bleb failure. Pupillary enlargement is easily accomplished under viscoelastic with either iris hooks (Fig. 31.10), a Beehler pupil dilator (Moria instruments), or multiple small sphincterotomies. Gently

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Fig. 31.9: Capsular fibrosis

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Fig. 31.10: Iris hooks in place

releasing any posterior synechiae and reinflating the chamber with a stiff viscoelastic, will often allow adequate capsulorrhexis and visualization. A fibrous circumferential band along the edge of the pupillary margin can occasionally be stripped gently with the capsulorrhexis forceps improving pupillary relaxation and dilation. The Graether pupil expander, or nylon iris retractors (Alcon Surgical) placed through 1 mm limbal paracentesis, are extremely helpful in not only stretching a miotic pupil, but in stabilizing the resulting lax and often floppy iris. This avoids repeated aspiration and trauma of the iris Fig. 31.11: Stretching the pupillary margin by the phacoemulsification tip that would otherwise occur with a simple stretching maneuver. The pupillary margin need not be brought all the way to the limbal opening to be effective (Fig. 31.11). Unfortunately, even gentle pupillary stretching will result in microscopic sphincter tears with breakdown of the blood-aqueous barrier, and fibrin formation. Experience with phacoemulsification techniques more suited to small pupils, such as “phaco-chop”, can be a tremendous advantage to the surgeon and allow minimal iris mani-pulation. Once the capsulorrhexis is complete, gently irrigating a portion of the viscoelastic from the anterior chamber will facilitate hydrodissection with less fluid pressure and avoid forcing excessive viscoelastic material into the sclerostomy and bleb.

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Fig. 31.12: Folded acrylic IOL prior to implantation

Fig. 31.13: IOL implantation

In cases of pseudoexfoliation or questionable zonular integrity, extra care should be taken to ensure the lens is completely hydrodissected and freely mobile within the capsular bag before beginning emulsification. As emulsification starts, adequate but not excessive infusion bottle height should be maintained to avoid dramatically elevated intraocular infusion pressures capable of producing a bleb rupture. Complete cortical clean-up and posterior capsular polishing should be performed prior to re-inflating the capsule with viscoelastic, to insert the IOL. The authors currently prefer an acrylic foldable IOL through an incision size of approximately 3.2 to 3.4 mm (Figs 31.12 and 13). The acrylic IOL (AcrySofTM, Alcon), compared to silicone, tends to collect fewer giant cell deposits, produce minimal capsular phimosis, and less frequently require a capsulotomy.26-28 Meticulous removal of the viscoelastic material is essential. It is recommended that the I/A tip be placed behind the IOL, as well as anteriorly to aspirate all residual viscoelastic. Careful aspiration is performed at the internal sclerostomy to remove as much of the same material which may have gained access to the bleb. A less retentive or more cohesive viscoelastic such as sodium hyaluronate is preferable during insertion of the IOL, because of the ease of removing this material completely. The anterior chamber is reformed with balanced salt solution, evaluating the bleb for formation and flow. Intracameral carbachol (MiostatTM or CarbostatTM) can be infused at the end of the procedure to reduce the possibility of a substantial postoperative IOP spike.1An otherwise self-sealing clear corneal incision may not function as such in patients with a low preoperative IOP. When in doubt, the incision should be sutured to ensure wound stability and to allow the possibility of mild digital massage by the surgeon postoperatively.

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Postoperative Considerations One of the most concerning postoperative occurrences is a severe IOP spike. A pressure of greater than 25 mm Hg in the immediate postoperative period has been associated with a significant increase in bleb failure.3 In a patient with a very precarious optic nerve or threatened fixation, we advocate IOP evaluation within a few hours of the cataract surgery to allow prompt initiation of medical therapy if needed. In cases where the pressure spike is extreme, aqueous can be immediately released through the paracentesis tract by simply depressing its posterior edge with a sterile instrument at the slit lamp. Frequent monitoring of the patient’s pressure over the ensuing hours may be necessary. Topical anesthesia for the cataract procedure, allows essentially uninterrupted frequent topical corticosteroid therapy to help reduce inflammation that can be associated with bleb compromise. The acute formation of fibrin resulting from iris manipulation may cause a dramatic IOP spike in the first few postoperative days. Obstruction of the internal sclerostomy by a fibrinoid clot or membrane, is the likely mechanism.29 These patients can be completely resistant to acute glaucoma medical management. We have experienced dramatic results with the use of intracameral tissue plasminogen activator (tPA) in such patients. The use of tPA to lyse fibrin clots in complicated glaucoma and cataract surgery has been well-described.12, 13 The prime concern in using this agent is the risk of an immediate and dramatic hyphema arising from the surgical site or an iris vessel cut during surgery. The occurrence of a hyphema with the use of tPA may be markedly reduced if the dose is kept between 6 and 12.5 µg.29 With a completely avascular clear corneal approach in the previously filtered eye and an appropriate tPA dose, hyphema appears much less likely based on our own experience in a limited number of cases. Gonioscopically, the fibrin may not be readily visible at the internal sclerostomy. The dramatic effect and immediate action of intracameral tPA can nonetheless be remarkable. It is injected with a small cannula through a preexisting paracentesis site under slit-lamp visualization. Up to 12.5 µg can be placed in the anterior chamber with simultaneous release of aqueous. The resulting drop in IOP can be dramatic, occur within minutes, and is usually sustained. We recommend considering prompt use of this adjunct in cases of extreme and unresponsive early IOP spikes. When IOP and postoperative inflammation are relatively stable beyond the first postoperative week, we recommend continuation of topical corticosteroids for at least four to six weeks with a slow taper. A delayed rise in the IOP beyond the first few weeks is generally indicative of late bleb failure. Although postoperative subconjunctival 5-FU injections may be reasonable in an attempt to avoid late failure, we are not aware of studies that support this. Sustained loss of IOP control requires the addition of glaucoma medications. As many as 10 percent of these eyes will require additional glaucoma surgery to regain pressure control.3 When indicated, the surgery should be performed promptly as the timing is not in any way restricted by the presence of a clear corneal cataract incision.

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Combined Bleb Revision Techniques In patients where augmentation of filtration is desirable, the surgeon is faced with several options at the time of cataract surgery. The two most commonly considered are revision of the filtering bleb, or primary filtration surgery at another site. Eyes considered ideal for bleb revisions are those that have demonstrated previously well-established bleb function, which has not yet been completely lost. Unlike the indications for primary filtration surgery, bleb revision should be considered, before resumption of maximum tolerated medical therapy is required. Rather than waiting until all bleb function is lost, a less complex revision technique in conjunction with the cataract surgery can be employed to improve bleb function.19 In cases where all bleb function appears to have been lost, it is still reasonable to consider one attempt to revise the bleb prior to performing a new filter at a different site. In selecting the type of revision procedure, preoperative gonioscopy is essential to establish the visibility and patency of the internal sclerostomy. Firm digital pressure by the surgeon 180 degrees away from the bleb may demonstrate transient expansion of the bleb or some degree of conjunctival elevation suggesting a reasonable chance of enhancing bleb function with an internal revision procedure combined with the cataract surgery. With evidence of a thickly encapsulated bleb or a firmly fibrosed scleral flap under favorable conjunctiva, bleb revision utilizing subconjunctival dissection may be effective. Internal Bleb Revision Internal revision of the bleb begins after insertion of the IOL. Additional viscoelastic is added to the anterior chamber as needed to firmly form the chamber and deepen the peripheral angle recess. The Zeiss four-mirror lens (Fig. 31.14) is used

Fig. 31.14: Zeiss four-mirror contact lens in place prior to internal revision of bleb

Fig. 31.15: Evaluation of sclerostomy site

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Fig. 31.16: Spatula tip passing underneath the scleral flap

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Fig. 31.17: Access to the sclerostomy from another angle

to re-evaluate (Fig. 31.15) and locate the internal sclerostomy. A cyclodialysis spatula is introduced through the clear corneal incision and directed toward the internal sclerostomy. The goniolens is briefly repositioned to allow visualization of the spatula tip fully entering the internal sclerostomy. Gentle pressure is applied in the direction of the sclerostomy to keep the tip fully engaged within the sclerostomy. The goniolens is removed and a second instrument can be used to apply counter traction by grasping the edge of a distal paracentesis tract. The spatula tip is gently pushed into the subconjunctival space passing underneath the scleral flap usually with mild resistance (Fig. 31.16). If substantial resistance is encountered, an additional paracentesis tract can be made in the clear cornea two or three clock hours away from the sclerostomy site allowing access to the sclerostomy from another angle (Fig. 31.17). Once the spatula has gained access to the subconjunctival space posterior to the scleral flap, it is moved in an arclike fashion to further open the scleral flap and free adjacent conjunctival adhesions. If desired the spatula tip can be carefully advanced further beyond the confines of the previous bleb into adjacent subconjunctival space allowing a more diffuse pathway for aqueous outflow beyond the fibrous wall of the bleb (Fig. 31.18). This latter maneuver can require a great deal of effort and it may be easiest to gain access to the more peripheral subconjunctival space at the nasal or temporal aspect of the original bleb. With a thin avascular localized bleb, extreme care must be taken when maneuvering the spatula to avoid rupturing the established bleb surface. The spatula is removed and the viscoelastic material is completely aspirated from the anterior and posterior chambers, and replaced with balanced salt solution which should spontaneously pass into the revised bleb. In many cases the bleb may now extend up to 360 degrees around the limbus (Fig. 31.19). A suture is used to close the corneal incision to maintain wound stability if the eye remains soft. Utmost care must be taken to ensure the spatula tip enters the internal sclerostomy to avoid inadvertent cyclodialysis and hemorrhage. In patients who

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Fig. 31.18: Spatula tip beyond the confines of the bleb

Fig. 31.19: BSS passing into the revised bleb

originally underwent filtering surgery with mitomycin-C, long-term postoperative hypotony may be encountered with this revision technique. It is reasonable to avoid an attempt to enlarge the confines of the bleb, which might otherwise invite long-term hypotony in these eyes. External Bleb Revision An external approach may allow improvement in bleb function when there is dense fibrous encapsulation or when the obstruction is due to fibrosis at the level of the scleral flap. Redissection of the scleral flap may be accomplished using a limbal or fornix-based conjunctival incision. Retrobulbar or peribulbar anesthesia and a corneal traction suture optimize exposure. Mitomycin-C may be applied once the conjunctiva is elevated, but prior to any attempt at re-opening the original scleral flap, ensuring no mitomycin-C enters the eye. To reduce the extent of the conjunctival dissection, it is reasonable to simply re-open one corner of the scleral flap to gain spontaneous aqueous outflow. Two or three sutures

Fig. 31.20: Limbal-based conjunctival incision prior to external revision

Fig. 31.21: Reopening of one corner of the scleral flap

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Fig. 31.22: External revision of the sclerostomy

Fig. 31.23: Sutured scleral flap after revision

Fig. 31.24: Tenon’s cysts before excision

Fig. 31.25: Excised cysts

can be used to control aqueous flow (Figs 31.20 to 23). The conjunctiva is closed in a watertight fashion. Postoperative laser suture lysis may be used to modulate scleral outflow.30 A large limbal-based incision may be used to dissect superficial conjunctiva off a Tenon’s cyst and expose the vast majority of the underlying cyst wall. Before excising the cyst, mitomycin-C can be applied around the base and adjacent Tenon’s capsule and episclera. All visible aspects of the cyst wall are then excised. The more anterior scleral flap is evaluated and dissected as needed to establish adequate outflow (Figs 31.24 and 25). An external approach to revise an encapsulated bleb or Tenon’s cyst has been described utilizing a small fornix incision. The technique utilizes a Kelly-Descemet punch to remove a portion of the cyst wall through this small incision.31 This approach does not readily allow the application of mitomycin-C. The postoperative care and complications of filtering bleb revision surgery are similar to primary filtration surgery. Frequently, the early postoperative pressure

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after a bleb revision procedure is less predictable than in primary filtration surgery. Potential complications include flat anterior chamber, hyphema, choroidal effusion, wound leaks, bleb failure, bleb infection, and endophthalmitis. Hypotony Maculopathy The prevalence of postfiltration hypotony maculopathy continues to increase as a result of more widespread use of mitomycin-C and longer patient follow-up. The tendency for cataract surgery to influence bleb function adversely has generated interest in the concept of utilizing cataract surgery to treat postfiltration hypotony maculopathy. Although some authors have advocated this mode of therapy, it has not been demonstrated to be reliable or predictable in resolving hypotony and its complications.3,32,33 SUGGESTIONS • Carefully evaluate the function of the preexisting filtering bleb preoperatively. • Determine whether mechanical pupillary dilation will be required at the time of surgery and weigh the pros and cons of iris manipulation against the potential for an increased rate of bleb failure. • Defer cataract surgery for at least six months or more after the establishment of a functional filter to improve long-term IOP control. • The preferred incision is in temporal clear cornea and just large enough to allow insertion of a foldable IOL. • Avoid bleb trauma related to manipulation, instrumentation and high infusion pressures. • If bleb survival is in doubt, consider a concurrent bleb revision procedure. • Suture the incision if the eye is soft or digital massage is anticipated postoperatively. • Use topical corticosteroids generously in the early postoperative period and consider an adjunctive topical nonsteroidal agent. • Consider postoperative 5-FU injections following combined internal revision and cataract surgery. • Intracameral tPA may salvage bleb function in the event of an early severe postoperative pressure spike unresponsive to standard therapy. REFERENCES 1. Caprioli J, Park HJ, Kwon YH et al: Temporal corneal phacoemulsification in filtered glaucoma patients (discussion). Trans Am Ophthalmol Soc 95:153-67, 1997. 2. Davison JA: Phacoemulsification in glaucomatous eyes. In: Thomas JV (Ed): Glaucoma Surgery (1st ed) CV Mosby: St. Louis, 295-314, 1992. 3. Chen PP, Weaver YK, Budenz DL et al: Trabeculectomy function after cataract extraction. Ophthalmology 105:1928-35, 1998. 4. Seah SKL, Jap A, Prata JA Jr et al: Cataract surgery after trabeculectomy. Ophthalmic Surg Lasers 27:587-94, 1996. 5. Dickens MA, Cashwell LF: Long-term effect of cataract extraction on the function of an established filtering bleb. Ophthalmic Surg Lasers 27:9-14, 1996. 6. Wygnanski-Jaffe T, Barak A, Melamed S et al: Ophthalmic Surg Lasers 28:657-61, 1997.

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7. Zaltas M, Schuman J, Shingleton B et al: Cataract extraction following filtering surgery. Invest Ophthalmol Vis Sci 35(ARVO suppl): 1420, 1994. 8. Foster RE, Lowder CY, Meisler DM et al: Extracapsular cataract extraction and posterior chamber intraocular lens implantation in uveitis patients. Ophthalmology 99:1234-41, 1992. 9. Shields ML: Combined cataract extraction and guarded sclerectomy—reevaluation in the extracapsular era. Ophthalmology 93:366-70, 1986. 10. Shields MB: Textbook of glaucoma (4th ed). Williams & Wilkins: Baltimore, 566, 1998. 11. Ferguson VMG, Spalton DJ: Continued breakdown of the blood aqueous barrier following cataract surgery. Br J Ophthalmol 76:453-56, 1992. 12. Lesser GR, Osher RH, Whipple D et al: Treatment of anterior chamber fibrin following cataract surgery with tissue plasminogen activator. J Cataract Refract Surg 19:301-05, 1992. 13. Ortiz JR, Walker SD, McManus PE et al: Filtering bleb thrombolysis with tissue plasminogen activator. [letter] Am J Ophthalmol 106:624-25, 1988. 14. Apple DJ, Solomon KD, Tetz MR et al: Posterior capsule opacification. Surv Ophthalmol 37(2): 73-116, 1992. 15. Naveh N, Kottas R, Glovinsky J et al: The long-term effect on intraocular pressure of a procedure combining trabeculectomy and cataract surgery, as compared with trabeculectomy alone. Ophthalmic Surg 21:339-45, 1990. 16. Murchison JF, Shields MB: An evaluation of three surgical approaches for coexisting cataract and glaucoma. Ophthalmic Surg 20:393-98, 1989. 17. Simmons ST, David L, Nichols DA et al: Extracapsular cataract extraction and posterior chamber intraocular lens implantation combined with trabeculectomy in patients with glaucoma. Am J Ophthalmol 104:465-70, 1987. 18. Kasahara N, Sibayan SA, Montenegro MH et al: Corneal incision phacoemulsification and internal bleb revision. Ophthalmic Surg Lasers 27:361-66, 1996. 19. Sofinski SJ, Thomas JV, Simmons RJ: Filtering bleb revision techniques. In: Thomas JV (ed): Glaucoma Surgery (1st ed). St. Louis, MO: Mosby; 75-82, 1992. 20. Wyse T, Meyer M, Ruderman JM et al: Combined trabeculectomy and phacoemulsification: a onesite vs a two-site approach. Am J Ophthalmol 125:334-39, 1998. 21. Warwar RE, Bullock JD, Ballal D: Cystoid macular edema and anterior uveitis associated with latanoprost use. Ophthalmology 105:263-68, 1998. 22. Dirscherl M, Straub W: Prophylaxis of cystoid macular edema after cataract surgery. Observation of an application of Chibro-Amuno. Ophthalmologica 200:142-49, 1990. 23. Flach AJ, Stegman RC, Graham J et al: Prophylaxis of cystoid macular edema without corticosteroids. A paired-comparison, placebo-controlled double-masked study. Ophthalmology 97:1253-58, 1990. 24. Ernest P, Tipperman R, Eagle R et al: Is there a difference in incision healing based on location? J Cataract Refract Surg 24:482-86, 1998. 25. Shingleton BJ (Ed): Surgical management of coexisting cataract and glaucoma. Boston, Ophthalmology Interactive,1996. 26. Hayashi K, Hayashi H, Nakao F et al Reduction in the area of the anterior capsule opening after polymethylmethacrylate, silicone, and soft acrylic intraocular lens implantation [see comments]. Am J Ophthalmol 123:441-47, 1997. 27. Hollick EJ, Spalton DJ, Ursell PG et al: Biocompatibility of polymethylmethacrylate, silicone, and AcrySof intraocular lenses: randomized comparison of the cellular reaction on the anterior lens surface. J Cataract Refract Surg 24:361-66, 1998. 28. Hollick EJ, Spalton DJ, Ursell PG et al: The effect of polymethylmethacrylate, silicone, and polyacrylic intraocular lenses on posterior capsular opacification 3 years after cataract surgery (discussion). Ophthalmology 106:49-54, 54-55, 1999. 29. Lundy DC, Sidoti P, Winarko T et al: Intracameral tissue plasminogen activator after glaucoma surgery. Indications, effectiveness and complications. Ophthalmology 103:274-82, 1996. 30. Savage JA, Condon GP, Lytle RA et al: Laser suture lysis after trabeculectomy. Ophthalmology 95:1631-38, 1988. 31. Shingleton BJ, Richter CU, Bellows AR et al: Management of encapsulated filtration blebs. Ophthalmology 97:63, 1990. 32. Sibayan SAB, Igarashi S, Kasahara N et al: Cataract extraction as a means of treating postfiltration hypotony maculopathy [case reports]. Ophthalmic Surg Lasers 28:241-43, 1997. 33. Allingham RR: Treatment of hypotonous maculopathy. In Epstein DL, Allingham RR, Schuman JS (Eds): Chandler and Grant’s Glaucoma (4th ed). Williams & Wilkins: Baltimore, 549, 1997.

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Luis W Lu Louis D Nichamin

Phacoemulsification in Patients with Significant Astigmatism

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INTRODUCTION Improved spherical and astigmatic outcomes are now well-recognized benefits of modern small incision cataract surgery. In fact, the term “refractive cataract surgery” no longer simply engenders a shift in philosophy, but rather has come to represent a reality for our cataract patients. The goal of astigmatism correction is to obtain the best possible vision without the use of corrective lenses after small incision cataract surgery. This is obtained by correcting the spherical component and the astigmatic component of the refractive error. Considerations Incision Decisions Over the past several years, a great deal of effort has centered upon the study of the astigmatic effects of various cataract incisions. By manipulating incision parameters (size, location, and shape) surgeons could, with a reasonable level of accuracy, “tailor” their astigmatic outcome according to the patient’s preexisting astigmatism.1 This on-axis, variable incisional approach does, however, require effort rotating about the operating room table, a dynamic mindset, and to some degree of varying instrumentation. Although effective, recent advances in incisional technique and implant technology have led to a different approach in managing astigmatism during phacoemulsification surgery.2,3 Specifically, the temporal clear corneal phaco incision, as popularized by I Howard Fine, has now proven itself to be safe, effective, and remarkably reproducible.4 Additionally, as a result of

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improvements in foldable intraocular lens (IOL) implantation delivery systems, implantation may now be routinely performed through incisions of 3.0 to 3.2 mm. Well-documented studies now support the clinical impression that incisions of this size behave in an essentially astigmatically neutral fashion.5,6 Thus, an incision may be easily and reproducibly crafted that yields all of the wonderful benefits of the clear corneal approach, yet is astigmatically neutral. If a patient has enough preexisting astigmatism to warrant reduction, modern astigmatic keratotomy (AK) may then be conservatively added to arrive at the desired cylindrical outcome. Admittedly, this approach may result in a greater number of incisions placed onto the cornea. However, use of peripheral (intralimbal) arcuate astigmatic relaxing incisions has proven to be extremely safe and reliable.7 In the setting of concomitant cataract surgery, our data indicates that this technique provides for more predictable astigmatic outcomes as compared to the use of conventional (smaller) AK optical zones, and yields more consistent results than when relying solely upon a “tailored” phaco incision. Our use of limbal relaxing incisions (LRIs) originated from the work of Stephen Hollis. With refinement of his nomogram, we found this approach to astigmatic keratotomy to be considerably more forgiving with less induced shift of resultant cylinder axis and greater predictability. This heightened safety level makes the technique most appropriate for the cataract-aged population where overcorrection should generally be avoided. Furthermore, this form of intralimbal keratotomy seems to logically dovetail with the trend toward clear corneal phaco incisions. Thus, we start with the amazingly simple but elegant single-plane, beveled (neutral) clear corneal phaco incision, and then add to it the necessary nonbeveled (perpendicular to the corneal surface) limbal arcuate relaxing incisions. This makes for a facile, logical and esthetic approach to astigmatism management. Correcting the Spherical Component Third-generation formulas are preferred for calculating the IOL power. In our experience the SRK/T formula appears to be the most accurate for patients with myopia and an axial length of 26.0 mm or longer. The third-generation Holladay 1 formula is indicated for eyes with an axial length between 24.5 and 26.0 mm. Hoffer Q and Holladay 2 formulas are preferred for those with less than 22.0 mm, and the average of the SRK/T, Holladay 1 and Hoffer Q for eyes between 22.0 and 24.5 mm. At present the IOL power calculations are based on the Hoffer 2.0 and Holladay 2 software. Correcting the Astigmatism Component About 5 percent of the patients seen for cataract surgery have astigmatism of less than 0.5D. In the remaining 95 percent, 75 percent have astigmatism of less than 1.25D.8 In our experience about 25 to 35 percent of cataract patients will be candidates for surgical correction of the astigmatism as an addition to their cataract surgery.

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The Surgical Plan It is generally agreed that mild residual with-the-rule (WTR) astigmatism might be desirable (when using monofocal IOLs), overcorrection (axis shift of 180 degrees) is undesirable, and that the refractive plan must take into account the status of the fellow eye.9 Some authors suggest a mild against-the-rule (ATR) astigmatism as the desirable outcome after cataract surgery.10 With this in mind, surgery is planned according to the nomogram (Table 32.1) as illustrated.11 Unfortunately, preoperative measurements – keratometry, refraction, and topography – do not always agree. We have found that keratometry provides the most accurate determination of axis, and refraction provides a more reliable indicator of the quantity of cylinder. Topography is helpful when measurements do vary and in complex cases, but is not a prerequisite for this technique. Phacoemulsification is performed through a 2.5- to 2.8-mm incision, depending upon the tip and sleeve combination, and is then enlarged to 3.0 to 3.5 mm to accommodate the particular fordable IOL. This single plane, paracentesis-style temporal incision is placed at or just anterior to the vascular arcade. If a larger incision is to be used (to accommodate a particular IOL), increased against-thewound drift (with-the-rule, given temporal incision location) must be anticipated and factored into the amount of cylinder to be corrected. As seen in the nomogram (Table 32.1), for patients with minimal preexisting astigmatism (+0.75×90 to 0.50×180), a single plane phaco incision is employed (Fig. 32.1). A 3.2 mm temporal clear corneal incision will induce 0.37 D of against-the-wound astigmatism.12 For patients with mild ATR astigmatism (+0.75 to +1.25D), the surgeon will have the option of a two-step grooved incision (300-600 microns groove) which can correct up to 0.75D,13 or a nasal peripheral arcuate relaxing incision placed opposite to the temporal clear cornea phaco incision leading to a nice, symmetrical corneal flattening (Figs 32.2 and 3). For moderate levels of ATR astigmatism (1.5 to 2.75D), a temporal arcuate incision is placed along with the nasal incision. This temporal cut, in essence, becomes a deep groove such that the incision architecture resembles the Langerman hinge (with the extent or length of the groove determined by the nomogram). For WTR astigmatism, the surgeon has two choices. There is varying opinion regarding the use of superior clear corneal incisions. Many leading surgeons fully advocate their use. We believe that it is acceptable to use a superior clear corneal incision provided that the patient has at least 2 diopters of WTR cylinder and good globe exposure. This most commonly occurs in young, myopic patients. One must keep in mind that these superior incisions will drift against the wound more than temporal incisions, as noted by Harry Grabow and others. In most cases of WTR astigmatism, we personally prefer to keep the phaco tunnel situated temporally, maintain an incision size of 3.5 mm or less for neutrality, and apply astigmatic keratotomy incisions over the steep axis (Figs 32.4 and 5). In our experience, this approach has yielded more consistent results with less corneal edema, particularly in those patients who have short eyes with small corneal diameters, are deeply set, or those who have compromised endothelium. A final

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Table 32.1: Nomogram for clear corneal phaco surgery • •

ASTIGMATIC STATUS = “SPHERICAL”: (+0.75 × 90o ↔ + 0.5 × 180o) Incision Design = “neutral” temporal clear corneal incision (3.5 mm or less, single plane, just anterior to vascular arcade) ASTIGMATIC STATUS = “AGAINST-THE-RULE”: Steep axis 0-30/150-180o Intraoperative keratoscopy determines exact incision location

Preoperative cylinder

+0.75 to +1.25

30-40

41-50

51-60

61-70

71-80

nasal limbal arc only

81-90

>90

35o

*paired limbal arcs on steep axis

55o

50o

45o

40o

35o

+1.50 to +2.00

*paired limbal arcs on steep axis

70o

65o

60o

55o

45o

40o

35o

+2.25 to +2.75

*paired limbal arcs on steep axis

90o

80o

70o

60o

50o

45o

40o

+3.00 to +3.75

*paired limbal arcs on steep axis

↓o.z. to 8 mm 90o

85o

70o

60o

50o

45o

↓o.z. to 8 mm 90o

degrees of arc to be incised * The temporal incision is made first by creating a two-plane, grooved phaco incision (600 µ depth), which is then extended to the appropriate arc length at the conclusion of surgery. •

ASTIGMATIC STATUS = “WITH-THE-RULE”: Steep axis 60-120o Intraoperative keratoscopy determines exact incision location Incision Design = “Neutral” temporal clear corneal along with the Following peripheral arcuate incisions

Preoperative cylinder

+1.00 to +1.50 +1.75 to +2.25

paired limbal arcs on steep axis arcs on steep axis

30-40

41-50

51-60

61-70

71-80

81-90

>90

50o

45o

40o

35o

30o

60o

55o

50o

45o

40o

35o

30o

+2.50 to +3.00

paired limbal arcs on steep axis

70o

65o

60o

55o

50o

45o

40o

+3.25 to +3.75

paired limbal arcs on steep axis

80o

75o

70o

65o

60o

55o

45o

degrees of arc to be incised • Acknowledgement is given to Dr Stephen Hollis whose original work provided the platform for this technique, and to Dr Spencer Thornton who has contributed so much to astigmatism surgery and whose modifiers are incorporated into this current nomogram. Drs David Dillman and William Maloney have also shared in the evolution of this nomogram.

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Fig. 32.1: Single-plane clear corneal incision

Fig. 32.2: Completion of surgery after twostep grooved clear corneal incision

Fig. 32.3: Pre- and postoperative corneal topography after LRI and temporal clear corneal incision for against-the-rule astigmatism

Fig. 32.4: First LRI over the steep axis for +1.75 D of with-the-rule astigmatism

Fig. 32.5: Second paired limbal arc of 45o in a 68-year-old patient

Fig. 32.6: Application of the Hoffer OZ marker

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Fig. 32.7: The 2 mm Grandon marker in place

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Fig. 32.8: After LRIs/CRIs for high with-the-rule astigmatism

planning note for patients who have WTR astigmatism, the side port incision location may need to be adjusted so as not to interfere with the intralimbal relaxing incision. Depending upon age, intralimbal relaxing incisions can address up to 3.5 diopters of astigmatism. For higher levels, corneal relaxing incisions placed at smaller optical zones become necessary (Figs 32.6 to 8). Well-established nomograms such as that of Dr Spencer Thornton or Richard Lindstrom may be used.14-16 Toric IOLs represent another option. Currently only one model is available in the US, but is available in two cylinder powers: 2.00 D or 3.5 D, which treat 1.00D to 1.25D or 2.00D to 2.5D of cylinder, respectively. The STAARR Toric IOL (AA4203TF) is designed for those cataract patients with 1.0 to 2.5 diopters of regular preexisting astigmatism. That is, symmetrical, “bow -tie” or “wedge” patterns. The anterior surface is a spherocylindrical refracting element and the posterior surface is a spherical lens to create a biconvex toric optic 6 mm in diameter. To ensure the power of the cylindrical correction is maximized, the surgeon is asked to use the two markings indicating the axis of the cylindrical correction of the lens and align them with the steep corneal meridian. The lens can be used in combination with LRIs to achieve the correction of high degrees of astigmatism.17 Excimer Laser Correction of Astigmatism In cases where a high degree of correction is desired, Excimer ablation is another option. The decision as to when to perform the refractive correction will depend as several factors such wound healing, size of the cataract incision, time until refractive stability, and presence and extent of previous limbal or corneal relaxing incisions. As in the case of LASIK, wound gape can be encountered upon the application of the suction ring. If further surgical correction is anticipated, consider creating a corneal flap that may be prepared prior to cataract surgery.

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The actual technique begins with verification of the steep meridian18 using intraoperative keratoscopy. We formerly would place all AK incisions at the conclusion of surgery, in the event that a complication necessitated a modification to the phaco incision. For routine cases, we now prefer to place these incisions at the outset in order to avoid epithelial disruption (Fig. 32.9). One exception would be in the case of high ATR astigmatism where the nomogram calls for a long arcuate incision. If this incision or “groove” is placed to its full arc length prior to phacoemulsification, significant gaping and edema may result secondary to intraoperative manipulation. In this situation, the temporal incision is made by first creating a two-plane, grooved phaco incision (600 microns depth) (Figs 32.10 and 11), which is then extended to the full arc length, as determined by the nomogram, at the conclusion of surgery (Fig. 32.12). The nasal arc may be extended to its full arc length at the beginning of the case. We must note that there may be greater astigmatic change produced by incisions made at the beginning of surgery because the cornea might be thinner and the IOP slightly higher.19

Fig. 32.9: Making the nasal LRI at the beginning of the case

Fig.32.10: Initial vertical 600 microns cut for the two-plane grooved phaco incision

Fig. 32.11: Completion of the two-plane clear corneal incision

Fig. 32.12: Temporal incision is extended at the conclusion of surgery

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The astigmatic incisions are placed just inside of the limbus at an empiric depth of 600 microns. Prior studies employing pachymetry and adjusted blade settings yielded negligible benefit in this older population, as opposed to younger refractive surgery patients where variable blade depth is justified. Diamond blade style and configuration may require an adjustment in depth settings; in our experience a triple-edged 15 degree Thornton arcuate diamond blade and the Katena 15 degrees diamond blade set at this depth have yielded excellent results with no perforations. A new diamond blade solely dedicated to this technique is now available from Mastel. A single footplate may improve visibility and the diamond extends to the appropriate (600 micron) preset depth. The extent of arc to be incised may be demarcated in several different ways. One of our preferred method makes use of a modified Mendez ring (Lu-Mendez fixation ring/degree gauge) that both fixates the globe and allows one to delineate the extent of arc by visually extrapolating from the limbus to the adjacent marker (Katena K3-6158). A similar method may be employed through the use of a specially designed Fine-Thornton fixation ring (Nichamin fixation ring and gauge by Mastel Precision and Rhein Medical) in which each incremental mark is 10 degrees apart, and bold marks 180 degrees apart serve to align with the steep axis. This approach avoids inking and marking of the cornea. If desired, a two-cut RK marker may be lightly inked and used to mark the exact extent of arc to be incised in conjunction with the fixation ring/gauge. Alternatively, a Thornton-Nichamin arcuate marker utilizing a 10-mm OZ may be used to mark the cornea (Moria). Interestingly, one of the most common patient complaints following contemporary phacoemulsification is that of a foreign body sensation. Intralimbal relaxing incisions, as compared to more central corneal incisions (smaller optical zones), definitely improve patient comfort. With the addition of a postoperative topical nonsteroidal antiinflammatory drugs (NSAIDs), this problem is virtually eliminated. Upon examination, these incisions appear to heal quickly and are nearly unidentifiable within several days. Potential complications related to LRIs/CRIs include infection, perforation, wound gaping, and clinically significant overcorrection. In over 10 years of performing CRIs and 5 years of LRIs, we have never seen a case of infection or perforation with this technique. Isolated cases of wound gape have been described. The present Nichamin’s nomogram is designed to avoid overcorrections. CONCLUSION This approach to astigmatism management has been evolving for the past five years, and parallels the development of several techniques such as keratolenticuloplasty (Kershner)20 and Gills’ use of Limbal relaxing incisions.7 Through these techniques both patient and surgeon may enjoy the great benefit of clear corneal surgery performed through an enlarged phacoemulsification incision, in concert with a safe and reproducible means to correct preexisting astigmatism.

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1. Amigo A, Giebel AW, Muiños JA: Astigmatic keratotomy effect of single-hinge, clear corneal incisions using various preincision lengths. J Cataract Refract Surg 24:765-71, 1998. 2. Vass C, Menapace R, Amon M et al: Batch-by-batch analysis of topographic changes induced by sutured and sutureless clear corneal incisions. J Cataract Refract Surg 22:324-30, 1996. 3. Fine IH, Hoffman RS: Refractive aspects of cataract surgery. Curr Opin Ophthalmol 7:21-25, 1996. 4. Ernst PH, Fenzl R, Lavery KT et al: Relative stability of clear corneal incisions in a cadaver model. J Cataract Refract Surg 21:39-42, 1995. 5. Lyle WA, Jin G: Prospective evaluation of early visual and refractive effects with small clear corneal incision for cataract surgery. J Cataract Refract Surg 22:1456-60, 1996. 6. Masket S, Tennen DG: Astigmatic stabilization of 3.0 mm temporal clear corneal cataract incisions. J Cataract Refract Surg 22:1451-55, 1996. 7. Gills J: Limbal Relaxing Incisions. ASCRS Seattle, WA, 1996. 8. Lu LW, Contreras C: Incidence of astigmatism in the cataract population. XIX PanAmerican Congress of Ophthalmology Caracas, Venezuela, 1993. 9. Grabow HB: Six steps to sphericity—An astigmatism management system for temporal, clearcorneal cataract surgery. ACES Ft. Lauderdale, 1997. 10. Trindade F, Oliveira A, Frasson M: Benefit of against-the-rule astigmatism to uncorrected near acuity. J Cataract Refract Surg 23:82-85, 1997. 11. Nichamin LD: Peripheral arcuate astigmatic keratotomy and modern clear corneal phaco surgery— a perfect match. ASCRS Seattle, WA, 1997. 12. Lu LW, Hollis S: Phacoemulsification in patients with high astigmatism. In: Lu LW, Fine IH (Eds): Phacoemulsification in Difficult and Challenging Cases. Thieme: New York, 33-39, 1999. 13. Langermann DW: Architectural design of a self-sealing corneal tunnel, single-hinge incision. J Cataract Refract Surg 20:84-88, 1994. 14. Fenzl RE: Relaxing incisions and wedge resection in astigmatism surgery. OSN Symposium, New York, 1997. 15. Thornton SP: Graded nonintersecting transverse incisions for the correction of idiopathic astigmatism. In Sanders DR (Ed): Radial Keratotomy: Surgical Techniques. Slack: Thorofare, 103-16, 1985. 16. Lindstrom RL, Lindquist TD. Surgical correction of postoperative astigmatism. Cornea 7:138-48, 1988. 17. Sanders DR, Grabow HB, Shepherd J et al: STAAR AA 4203T toric silicone IOL. In Martin RG, Gills JP, Sanders DR (Eds): Foldable Intraocular Lenses. Slack: Thorofare, 237-50, 1993. 18. Susuki A, Maeda N, Watanabe H et al: Using a reference point and videokeratography for intraoperative identification of astigmatism axis. J Cataract Refract Surg 23:1491-95, 1997. 19. Koch DD: Pearls in performing peripheral corneal relaxing incisions. Vision News 6:2, 1999. 20. Kershner RM: Keratolenticuloplasty—arcuate keratotomy for cataract suregery and astigmatism. J Cataract Refract Surg 21:274-77, 1995.

Enrique Chipont Jorge L Alio

Cataracts in Patients with Uveitis

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INTRODUCTION The indications for proceeding with cataract surgery are more demanding in eyes with uveitis. The reported incidence of cataract in uveitic patients varies between series but it approaches 50 percent in juvenile rheumatoid arthritis1 and other forms of posterior uveitis2 and up to 75 percent in chronic anterior uveitis.3 Also complications of this surgery are higher in these patients than in no uveitic patients. Uncontrolled inflammation, hypotony, phthisis bulbi, among others are important challenges to the postoperative period in uveitic patients.4 The time of surgery has to be justified on eyes with slightly decrease in visual acuity, but in functional vision that are not in danger of visual loss, but on the other hand we cannot delay the surgery so long that treatable problems worsen progressively the status of the eye. The improvement in surgical techniques and pre- and postoperative control of inflammation thanks to new and safer small incision surgeries and the usage of corticosteroids pre- and postoperatively have lead to better results of surgery in patients with uveitis. This has increased the tendency to operate these eyes earlier and earlier to prevent more important complications. Surgery should be performed when the inflammation of the eyes is quiet. However, in some patients, it is impossible to clear every cell from the anterior chamber or vitreous. Furthermore, in patients with dense cataracts and primarily vitreoretinal inflammation, it is impossible to assess the activity of the disease behind the cataract. Clinical Presentation Complaints in those patients associated with the development of cataract will depend on age, the type of uveitis and mostly the type of cataract. Decrease of visual acuity

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is the most important symptom of the development of cataract in patients with uveitis. Glare, and sometimes halo symptoms can be described by the patient as the first complaint. Glare can be associated with subcapsular posterior cataract, anterior Tyndall effect, intermediate uveitis or glaucoma that must be ruled out in such patients. The control of the intraocular inflammation is needed prior to the surgical procedure. This preoperative control may require the use of topical or systemic steroids or immunosuppressive drugs. The treatment should be aimed at achieving a reduction in cellularity in the anterior chamber as well as little or no vitreous activity. The inflammatory activity should be assessed—by the presence of cells in the anterior chamber and not—by the amount of flare presence.5 Cataract surgery is sometimes complicated by the presence of iris atrophy, sclerosis of the pupillary sphincter, cyclitic membranes, posterior synechiae, anterior capsular sclerosis, and possible hemorrhage from the iris and angle neovascularization. A precise and delicate surgery is mandatory. Keep in mind that surgery can exacerbate the underlying inflammatory process by the release of lens material and by the surgical trauma itself. It is then very important that the surgery should be performed in an undisturbed eye with an inflammatory reaction that has been controlled for at least three months prior to surgery. The firm control of the postoperative inflammation is imperative. The necessary use of topical and in most cases, periocular and systemic steroids can give rise to problems as steroids dependent ocular hypertension and even problems related to the progressive and full withdrawal of them. The use of NSAIDs is a step forward in the postoperative control of inflammation. Surgical Indications There are two main indications for cataract surgery in patients with uveitis: (i) visually significant cataract if prospects for substantial improvement in visual acuity are good, and (ii) cataract that impairs fundus assessment in a patient with suspected fundus pathology. Visually Significant Cataract Cataract is not a reversible disease, so a detected decrease in visual acuity due to cataract precludes a subsequent decrease in few years. Techniques to estimate postoperative visual acuity can be used in patients where standard acuity scales are not sufficient and the health of the macula is unclear. Potential acuity meter (PAM) and Laser Interferometry are the most reliable techniques in these patients Glare Sometimes a 20/20 visual acuity is present in a patient with uveitis that complaint of blurred vision. Explanation of the potential risks and benefits must be carefully given including the fact that cataract is not reversible and that those symptoms will augment with time.

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Improvement of Posterior Pole Visualization Those situations associated with visualization of the posterior pole either to a given disease—diagnose or to observe and assess its evolution (e.g. posterior uveitis, vasculitis, macular edema) or the response to a treatment (systemic steroids or immunosuppressants). Such observations can be hindered by the presence of a dense cataract or even a wide posterior subcapsular cataract. Preoperative Management The single most important sign of inflammation is presence or absence of inflammatory cells in the anterior chamber or vitreous. Aqueous flare in anterior chronic uveitis simply denotes vascular incompetence of the iris and ciliary body, a consequence of vascular damage from recurrent uveitis. Therefore flare should in general not be used as a guidepost for inflammatory quiescence. Our approach includes that patients will be divided into two groups: complicated cases and noncomplicated cases.6 Complicated patients are those in whom systemic or periocular therapy is necessary to maintain uveitis in a quiescent state or those in which surgery itself is expected to be difficult by the surgeon. Noncomplicated patients are those on topical steroids and in those in whom surgery is expected to be easy. The therapeutic approach will begin one week before surgery. Each subject will be given a topical corticosteroid (prednisolone acetate 1% or dexamethasone phosphate 0.5%) one drop four times daily. All subjects classified as “complicated” cases will also receive 1 mg/kg/day of oral predisone. After the operation treatment will be continued in each group in the way that will be described in the forward “postoperative treatment”. Surgical Technique Intracapsular surgery is reserved for the situations in which an important phacoinduced component is revealed in prior contralateral surgery. In case a chronic macular edema, a combined anterior and posterior procedure should be performed. Most surgeons opt for conventional pars plana vitrectomy techniques.5 Cataract surgery is sometimes complicated by the presence of iris atrophy, sclerosis of the pupillary sphincter, cyclitic membranes, posterior synechiae, anterior capsular sclerosis, and possible hemorrhage from the iris and angle neovascularization. A precise and delicate surgery is mandatory. Phacoemulsification allows a small wound, causes minimal trauma and may therefore minimize postoperative inflammation. Young patients and patients on high doses of corticosteroids are at an advantage with this technique. General anesthesia is not necessary (though many patients are young requiring general anesthesia locoregional anesthesia by retrobulbar or peribulbar block are preferred. Topical anesthesia is not contraindicated but we do not use it in these cases.7

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Clear corneal or scleral tunnel incision can be performed. Clear corneal incision has some advantages over scleral tunnels such as the absence of postoperative hyphemas, filtering blebs and need for cautery among others. This is our favored approach if no lens or a foldable lens is implanted. If the implantation of a rigid PMMA lens is planned a limbal approach with a short scleral tunnel is performed. Viscoelastic substances are routinely used to release adhesions and aid mydriasis. Combinations of hyaluronic acid and chondroitin sulfate (Viscoat R) are preferred, and high viscosity viscoelastics can be used (Healon GV R, Amvisc plus R). Many patients with uveitis have sclerosis of the dilator muscle of the pupil or intense posterior synechiae. In such cases, under viscoelastic aid synechiolysis is performed with an iris spatula. If further mydriasis is desired we use four De Juan hooks placed at each quadrant through four small corneal incisions. Continuous circular capsulotomy (capsulorrhexis) is always performed, even in intumescent cataracts, and if this is not possible a can-opener capsulotomy is opted for, but phacoemulsification is performed with caution. The phacoemulsification procedure is accomplished by the most suitable technique for each case, with chop techniques if hardness of the nucleus is high. In general the nucleus is soft in young patients and phacoemulsification can be performed without any complications. Intensive cortical cleaning is mandatory to eliminate one of the sources of postoperative inflammatory reaction. The posterior surface of the anterior capsule must be aspirated with a low vacuum to eliminate proliferative cells and to remove one of the sources of posterior and possibly anterior capsule opacification. Bimanual techniques give excellent results in anterior cortical cleaning. Where there is extensive membrane formation in the vitreous especially in the anterior part, vitrectomy after posterior central capsulorrhexis must be considered. If the vitreous cavity shows extensive fibrosis and exudate formation, transscleral pars plana vitrectomy may be indicated.8 INTRAOCULAR LENSES Several researches have suggested that inserting a posterior chamber lens into the capsular bag poses no additional threat to ocular morbidity in selective uveitis cases, providing proper perioperative treatment for inflammation is given.9,10 Surface-modified IOLs such as the heparin-coated models have been introduced. The heparin surface-modified IOL is created by inducing electrostatic absorption of heparin onto the surface of a PMMA IOL. Heparin-coated IOLs are recommended for patients with uveitis as they decrease the number and severity of deposits on the surface of the IOL.11 Limited information is available regarding small incision phacoemulsification and foldable IOL implantation in patients with chronic uveitis. Several controlled studies comparing flexible IOL implantation through a 3.2 mm incision and conventional PMMA IOL implantation through 5.5 mm or larger incisions have been reported. Postoperative inflammation has been significantly less with smaller incisions.

CATARACTS

Fig. 33.1: Posterior synechiae

Fig. 33.3: Hypopyon

Fig. 33.5: Endothelial precipitates

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Fig. 33.2: Pupillary membrane

Fig. 33.4: Pupillary seclusion

Fig. 33.6: Posterior subcapsular cataract

Polymethylmethacrylate (PMMA) is the most commonly used IOL material. It has proved to be inert and stable. Design and manufacture have been optimized over decades.12 New materials like silicone and hydrogel have been progressively accepted for intraocular implants in humans because phacoemulsification is becoming

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Fig. 33.7: Severe pupillary membrane and synechiae

Fig. 33.8: Deficient mydriasis

more popular. The interest for these materials is based on their mechanical properties, which allow them to be folded and inserted through a small incision. New technology applied to PMMA lenses has enabled the development of a new generation of acrylic foldable lenses for small incision surgery.13 Silicone lenses have displayed greater inflammatory reaction after ECs in nonuveitic patients when compared with other types of lenses (PMMA, heparin-modified, hydrogel). After phacoemulsification procedures a number of complications have been described such as intense inflammatory reactions in the anterior chamber, the total closure of the capsulorrhexis14 and an increase in posterior capsule opacification when compared with PMMA implants. The use of this material in patients whose blood-aqueous barrier is affected is not accepted by many authors. Nevertheless few reports of the use of silicone IOLs in patients with uveitis have been published. A 13 mm silicone IOL with 6 mm optic was implanted through a 3.2 mm incision in a woman with sarcoidosis uveitis; this case revealed perioperative tolerance to the silicone implant and rapid visual rehabilitation compared with the fellow eye which received a rigid PMMA lens. Few reports about the use of this material are available, though a prospective study may be able to establish some indications as to this silicone IOL. The issues surrounding IOL placement in uveitic eyes after cataract extraction remains a key concern in management of the uveitic patient. Many features unique to a uveitic eye must be considered, including different types of uveitis and their diagnoses, preoperative inflammation and treatment, postoperative inflammation and specific complications. With newer techniques and modern posterior chamber lenses, IOLs are being implanted with fewer complications. These IOLs are well tolerated in selected patients, especially when the lens is placed in the capsular bag. Many questions remain unanswered regarding the uveitic eye in conjunction with IOL biocompatibility and inflammation. Valuable information can be gained through more experience with IOL use in these eyes.

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Because the heterogeneity and the scarce number of patients, multicentric studies are needed to determine which, if any, IOL material is better tolerated in a uveitic patient by evaluating postoperative responses in the operative eye. This will be accomplished by descriptively comparing the postoperative outcomes of these eyes when implanted with IOLs made of various materials. Outcomes will be determined by measuring visual acuities and postoperative parameters such as posterior capsule opacification, inflammatory responses and endothelial cell counts. COMBINED SURGERIES Glaucoma Glaucoma associated with uveitis is one of the most serious complications of intraocular inflammation. It occurs in various syndromes and it may be difficult to manage. Most patients respond poorly to surgery. It is of primary importance to determine the severity of the inflammation and if possible, the syndrome associated with it. Management includes treatment of the underlying inflammation and of the glaucoma itself. Various mechanisms produce secondary glaucoma, and it is important to identify them to institute the appropriate therapy. Special considerations should be given to the management of acute or chronic intraocular inflammation and to make it certain that corticosteroids are not the cause of the elevated pressure. Pharmacologic intervention is the first step in the treatment of uveitic glaucoma. Corticosteroids, acetazolamide, beta-blockers, cycloplegics, etc. In general the results of the surgery for glaucoma in uveitic patients is not as good as it is for glaucoma in patients without uveitis. The following procedures can be performed: laser iridectomy, surgical iridectomy, trabeculodialisis, trabeculectomy, trabeculectomy with wound modulation therapy, ab interno laser sclerostomy, drainage implantation, cycloablation therapy. Cataract-Vitrectomy Combined phacoemulsification and pars plana vitrectomy technique has displayed many advantages over other techniques.15,16 A small incision (even 3.00 mm) guarantees minimal corneal distortion and manipulation. These incisions are water-tight so they allow perfect closure during the vitrectomy portion of the operation. Lens density is not a main problem for phacoemulsification and allows the posterior capsule to remain intact, enabling endocapsular fixation of a posterior chamber lens. Delaying the IOL implantation until completion of vitrectomy, if required, allows fast visual rehabilitation and functional unaided vision in patients who are considered poor candidates for aphakic contact lens wear. If a limbal approach to the cataract and posterior pars plana vitrectomy is intended, the scleral incisions for the vitrectomy should be made first. The upper sclerotomies are occluded with scleral plugs. The advantage of this procedure lies in preserving part of the posterior capsule for the secondary implant of an IOL. We prefer this approach whenever possible, first performing phacoemulsification of the crystalline lens followed by pars plana vitrectomy.

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A capsulotomy or posterior capsulorrhexis must be performed on completion of the vitrectomy due to the fast opacification occurring and because it allows the decompartmentalization of the eye, facilitating the access of anti-inflammatory drugs in the postoperative stage. Postoperative Inflammation The clinical consequence of inflammation is represented by a transient or permanent blood-aqueous barrier rupture. This is a common phenomenon that usually appears associated to the postoperative surgical inflammation. This is mostly subclinical and difficult to detect by biomicroscopy. Clinically it is very difficult to establish if that inflammation has vanished definitively. This subclinical inflammation can only be measured with most modern procedures like fluorophotometry and the laser flare cell meter. This technique can explain some clinical events such as late endothelial decompensation, not explained by clinical reasons. The common clinical features of postoperative inflammation include the presence of cells, leukocites and proteins flare in the anterior chamber and engorgement of the iris and conjunctival vessels. In clinical practice, it is standard to monitor the resolution of postoperative inflammation by observing the level of cells and flare in the anterior chamber for four to six weeks postoperatively. Slit lamp biomicroscopy is used to detect and aid the physician in assessing the extent of anterior chamber inflammation and engorgement of the conjunctival vasculature. In human clinical studies of post-surgical inflammation the primary clinical variable examined to assess is the degree of postoperative intraocular inflammation. The presence of cells and flare in the anterior chamber are mandatory. It is measured with the laser flare cell meter, fluorophotometry, or an inflammation severity score, i.e. uveitic scoring system (USS).17 Secondary measures of treatment efficacy include the degree of ocular discomfort, bulbar conjunctival hyperemia, ciliary flush, corneal edema, an even anterior vitreous reaction. In addition, the frequency of treatment failures and the follow-up impression of inflammatory response must be assessed. Measuring the degree of blood-aqueous barrier (BAB) disruption was difficult in the 1970s. With development of the fluorophotometer and the laser flare cell meter, however, the task has been simplified, allowing the BAB function to be used as a physiological, clinical parameter. The laser flare meter has been especially useful because it is noninvasive and easy to perform. Recent studies suggest that capsule opacification is a form of postoperative inflammatory reaction. Because the lens capsule is primarily composed of collagen type IV, Miyake et al18 performed an experimental study to compare PMMA IOLs with collagen type IV mediators implanted inside the lens capsule. They found that eyes receiving the collagen type IV mediators had less severe postoperative inflammation and less anterior capsule opacification.18 Topically applied steroids have become the standard of care during the immediate postoperative period to reduce the morbidity associated with ocular inflammation, to prevent structural damage to the eye, and to reduce patient’s discomfort.19 Their potential side effects limit their clinical effectiveness in some settings. This is

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particularly true for steroids that have a predilection for elevating IOP. A current strategy underlying the development of new steroidal compounds for ocular use is therefore, to identify drugs that exhibit marked antiinflammatory activity while decreasing the propensity to raise IOP or induce other side effects. In emergency cases, no strict guidelines are available. When a previous uveitis is present a severe postsurgical exacerbation of preexisting inflammation should be expected. Depending on the severity of the case one week prior to surgery topical or systemic corticosteroids should be administered. At the time of surgery a subconjunctival corticosteroid should be injected subconjunctivally far from any ocular wounds. During the postoperative period both topical and systemic corticosteroids may be tapered based on the severity of ocular inflammation. In the most severe cases moderate to high doses of oral prednisone from 1 to 1.5 mg/kg/day, and intensive once per hour topical corticosteroids drops should be given prior to and tapered after surgery. In cases of steroid-induced glaucoma, the management may be much more difficult. In these cases temporary immunosuppressive therapy may need to be substituted to control inflammation in the very operative period. These guidelines may be applied for all intraocular procedures in uveitis eyes. Several recent studies have assessed the effectiveness of NSAIDs to treat ocular inflammation. Most NSAIDs used today act by inhibiting the enzyme cyclo-oxygenase and thereby decreasing the formation of prostaglandins which play a major role in ocular inflammation by producing and maintaining the rupture blood-aqueous barrier. Diclofenac drops were shown to reduce inflammation after argon laser trabeculoplasty,20 and after cataract surgery.21 We cannot offer these drugs as an alternative to corticosteroids or even as an adjunct to treatment in uveitis patients with cataract. FOLLOW-UP Generally a low inflammatory reaction is observed after IOL implantation in patient with chronic anterior uveitis if preoperative and postoperative antiinflammatory measures are undertaken. Complications associated with these patients in the followup are linked with the following. Posterior capsule opacification at least in 50% of cases.22

This complication has been described in some series

Membranes The appearance of fibrous membranes mostly in pars planitis patients has been described.23 Decreased visual acuity The major causes of decreased visual acuity in these patients are cystic macular edema (CME),5 Epiretinal membrane,24 and glaucomatous optic nerve damage.5 Nevertheless a proper visual acuity was achieved in the majority of patients in the most important series of patients published.24,25 Visual acuities better than 20/40 can be achieved in 20 to 75 percent of patients.26,27

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ADDENDUM Multicentrical International Intraocular Inflammation Society (IOIS) Study Protocol The issues surrounding intraocular lens (IOL) placement in uveitic eyes after cataract extraction remains a key concern in management of the uveitic patient. Many features unique to a uveitic eye must be considered, including different types of uveitis and their diagnoses, preoperative inflammation and treatment, postoperative inflammation and specific complications. With newer techniques and modern posterior chamber lenses, IOLs are being implanted with fewer complications. These IOLs are well tolerated in selected patients, especially when the lens is placed in the capsular bag. Many questions remain unanswered regarding the uveitic eye in conjunction with IOL biocompatibility and inflammation. Valuable information can be gained through more experience with IOL use in these eyes. The objective of the study is to determine which, if any, IOL material is better tolerated in a uveitic patient by evaluating postoperative responses in the operative eye. This will be accomplished by descriptively comparing the postoperative outcomes of these eyes when implanted with IOLs made of various materials. Outcomes will be determined by measuring visual acuities and postoperative parameters such as posterior capsule opacification, inflammatory responses and endothelial cell counts. Test articles for this study include silicone AMO Model SI-40NB, Alcon soft acrylic Models MA60BM and MA30BA, PMMA Pharmacia Model 720A and heparin surface modified PMMA Pharmacia Model 720C. Timing of the Procedure (IOIS recommendations) One week before surgery, each subject will be given a topical corticosteroid (prednisolone acetate 1% or dexamethasone alcohol 0.5%) one drop four times daily. All subjects classified as “complicated” cases will also receive one (1) mg/kg/day of oral predisone. Surgery must be as atraumatic as possible. A minimum three month quiescent state is required prior to surgery. Quiescence will be defined by grade 1 (USS). Following a three-month quiescent state, surgery will be performed under mydriasis. Preoperative mydriasis and antiinflammatory treatment will be achieved by instillation of: Voltaren

Total 8 drops dosed 2 drops every 15 minutes one hour before surgery

Atropine 1%

Total 1 drop dosed one hour before surgery

Tropicamide 1%

Total one drop “ad libitum”

Phenylephrine 10%

Total 1 drop one-half hour before surgery.

Clear corneal or limbal/corneal incisions sized 6 mm or less must be used. A circular continuous tear capsulorrhexis must be performed to open the anterior capsule.

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All IOL implantations will occur after phacoemulsification cataract extraction. The IOL, including both haptics, should be placed into the capsular bag. An intracameral solution of Zinacef R (cefuroxime) (1 mg/0.1 ml) may be injected at the end of surgery to prevent infection. Alternatively, a subconjunctival injection of an appropriate antibiotic may be given. A sub-Tenon or subconjunctival injection of a nondepot steroid (betamethasone, 4 mg soluble) will be given. Tobramycin ointment and patching should be given routinely when surgery is completed. Postoperative medications During the first two postoperative weeks, Maxitrol should be administered four times a day. During the third postoperative week, one drop of Maxidex or Predforte 1% should be instilled every 12 hours. During the fourth postoperative week, one drop of Maxidex or Predforte 1% should be instilled every 24 hours. REFERENCES 1. Kanski JJ, Shun Shin GA: Systemic uveitis syndromes in childhood—an analysis of 340 cases. Ophthalmology 91: 1247-52, 1984. 2. Tabbara KF, Chavis PS: Cataract extraction in patients with chronic posterior uveitis. Int Ophthalmol Clin 35: 121-31, 1995. 3. Ram J, Jain S, Pandav SS: Postoperative complications of intraocular lens implantation in patients with Fuchs hetrerochromic cyclitis. J Cataract Refract Surg 21: 548-51, 1995. 4. Kaplan I IJ, Fong LP, Singh C: Cataract surgery and intraocular lens implantation inpatients with uveitis. Ophthalmology 96:287-88, 1989. 5. Hooper PL, Rao N: Cataract extraction in uveitis patients. Surg Ophthalmol 35:120-45, 1990. 6. Alio JL, Chipont E: Multicentrical IOIS study on surgery of cataract in the uveitic patient. First combined International Symposium on Ocular Immunology and Inflammation. Amsterdam June 1998. (Personal communication). 7. Alió JL, Ben Ezra D, Chipont E: Cataract in patients with uveitis. Symposium on cataract IOL and refractive surgery. Seattle April 1999.(Personal comunication). 8. Alió JL, Chipont E: Inflamación en Cirugía de la catarata. Inflamaciones Oculares Ed EDIKAMED: Barcelona, 407-28, 1995. 9. Alió JL, Chipont E, Sayans JA: Flare-cell meter measurement of inflammation after uneventful cataract surgery with intraocular lens implantation. J Cataract Refract Surg 23: 935-39, 1997. 10. Lowenstein A, Bracha R. Lazar L: Intraocular lens implantation in an eye with Behcet’s uveitis. J Cataract Refract Surg 17:95-97, 1991. 11. Percival SPB, Pai V; Heparin-modified lenses for eyes at risk for breakdown of the blood-aqueous barrier during cataract surgery. J Cataract Ref Surg 19: 760-65, 1993. 12. Drews RC: Lens implantation lessons learned from the first million. Trans Ophthalmol Soc UK 102:505-09, 1982. 13. Alió JL, Sayans J, Chipont E: Laser flare-cell measurement of inflammation after uneventful extracapsular cataract extraction and intraocular lens implantation. J Cataract Refract Surg 22:775-79, 1996. 14. Martinez JJ, Artola A, Chipont E: Total anterior capsule closure after silicone intraocular lens implantation. J Cataract Refract Surg 22:269-71, 1996. 15. Koening SB, Han DP, Msfieler WF: Combined phacoemulsification and pars plana vitrectomy. Arch Ophthalmol 108:362-64, 1990. 16. MacKool RJ: Pars plana vitrectomy and posterior chamber intraocular lens implantation in diabetic patients. Ophthalmology 96:1679-80, 1989. 17. Ben Ezra D, Nussemblat RB, Timonen: Uveitis Scoring System (USS). Springer-Verlag: Berlin 1990.

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18. Miyake K, Maekubo K, Gravagna P: Collagen IOLs—a suggestion for IOL biocompatibility. Eur J Implant Refract Surg 3: 99-102, 1991. 19. Jaanus SD: Anti-inflammatory drugs In: Bartlett JD, Jaanus SD (Eds): Clinical Ocular Pharmacology. Butterworth: Boston, 163 -97, 1989. 20. Herbort CP, Mermoud A: Antiinflammatory effect of Diclofenac drops after argon laser trabeculoplasty. Arch Ophthalmol 111: 481-83, 1993. 21. Othenin P, Borruat X: Association diclofenac- dexametasone dans le traitement de línflammation postoperatorie. Klin Monatsbl Augenheilkd 200: 362-66, 1992. 22. Akova YA, Foster CS: Cataract surgery in patients with sarcoidosis-associated uveitis. Ophthalmology 101: 47379, 1994. 23. Tessler HH, Faber MD: Intraocular lens implantation versus no implantation in patients with chronic iridocyclitis and pars planitis. Ophthalmology 100: 1026-29, 1993. 24. Kaufman AH, Foster CS: Cataract extraction in patients with pars planitis. Ophthalmology 100: 1210-17, 1993. 25. Foster CS, Barrett E: Cataract development and cataract surgery in patients with juvenile rheumatoid arthritisassociated iridocyclitis. Ophthalmology 100(6): 809-17, 1993. 26. Moorthy RS, Rajeev B, Smith RE et al: Incidence and management of cataract in Vogt- Koyanagi-Harada syndrome. Am J Ophthalmol 118: 197-204, 1994. 27. Loffler KU, Meyer JH, Wollensak G et al: Success and complications of rTPA treatment of the anterior eye segment. Ophthalmologe 94: 50-52, 1997.

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Corneal Endothelium and its Protection in Phacoemulsification

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THE IMPORTANCE OF THE ENDOTHELIUM The transparency of the cornea depends on its lack of blood vessels, on a gratelike distribution of the collagen fibers of corneal stroma, and its relative lack of water. Deturgence of the cornea is maintained by the endothelium and the epithelium. Damage to the epithelium only leads to a light localized swelling of the cornea which, disappears as soon as epithelium regenerates through cell division. For the clarity of the cornea the endothelium has a far greater significance. The endothelium is a single-layered structure of flat, hexagonal or cuboidal cells, applied to the posterior layer of the Descemet’s membrane. According to Maurice 1972, the endothelium dehydrates the cornea by pumping the water against the hydrostatic pressure into the anterior chamber. As an intact cell layer the endothelium passively prohibits the diffusion of the molecules into the corneal stroma. This fact further contributes to the low water content of the cornea. The cornea normally has a relative constant thickness of 500 microns and has water content of 75 to 80% (Cotlier 1970). If the endothelium is badly damaged, water enters the stroma, causing it to swell thus; the collagen fibers separate from each other, and loose the crystal-like distribution. Clinically this means clouding of the cornea. This stromal change leads to edema of the corneal epithelium. EVALUATION OF THE ENDOTHELIUM: THE ENDOTHELIAL MICROSCOPE In 1968 Morris described a specular microscope for observation of the endothelium of the enucleated eye. Laing in 1975 and Bourne and Kaufman in 1976 subsequently modified this instrument, so that one could examine the patient in the sitting position.

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The procedure was subsequently termed as clinical endothelium microscopy. Endothelial (specular) microscopes can be of two types: contact and non-contact. Contact Endothelial Microscope The advantage of a contact system is that you can examine a larger area with sharper and better illumination. However these units are commonly utilized for clinical research and are comparatively costly. A good example of the contact endothelial specular microscope is the Keeler-Konan microscope. In contact microscopy, the objective of the instrument is brought in direct touch with the cornea which it applanates. The applanation to some extent, controls the fine movement of the eye, so that the picture sharpness is enhanced. Without the contact element, the image quality diminishes. This is due to a higher difference between the refractive index of the cornea and the air (difference = +0.376). In addition there is much more pronounced scattering of light by the inhomogeneities of the tear film and by the unevenness of the epithelial surfaces (Bigar, 1982). Non-contact Endothelial Microscope They can be fully dedicated units like the Topcon specular microscope, which can automatically change focus and take the flash photograph to get the best possible picture. These units are much more economical and far faster to use and, being non-contact, are very patient friendly. The other alternatives are the simple attachments on to a slit lamp or, better still a photo slit lamp. The early specular attachments were made by both Zeiss and Nikon, but were designed to specifically fit only their own slit lamps. BioOptics EMH 1000 made a small attachment, very much like the barrel of a regular microscope, which could be fitted on any slit lamp. McIntyre made a reticule, which could be introduced into the Zeiss slit lamp. Used at a fixed 40X magnification it could grade the cells into four categories of 4000, 2000, 1000 and 500 cells mm.2 The limitations of all these instruments are that it is never possible to exactly photograph the same area again and hence serial photographs become very difficult. Hence, there is always a statistical variation, which has to be taken into account in considering these cell counts. The wide field endothelial microscope by increasing the area of photographs, diminishes this problem, enhances accuracy, permits a more meaningful analysis of cell morphology and density, and is a more sensitive indicator of endothelial cell changes and stress (Glasser DB et al, 1985). VARIATIONS IN ENDOTHELIAL CELL COUNT The total endothelial cell count at birth is high—in the range of 6500 to 7000 cell/ mm2. While mitosis may occur in the very young endothelium, it is infrequent in adults (Bron and Tripathy, 1997). There is great individual variation in cell counts. A gradual decrease in density and increase in shape variation (polymegathism) occurs with age (Shaw, 1978). In youth the cells are predominantly hexagonal, but become more polymorphic with increasing age. Sherand Novakovics and Speedwell (1987)

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suggest that the endothelial density is around 6000 cell/mm2 at birth and falls by 26 percent in the first year. A further 26 percent is lost over the next 11 years but the rate of cell loss decreases and stabilizes around middle age, especially in polymegathous endothelium (Blatt, Rao, Aquavella, 1979). Healing of Lost Endothelial Cell Areas Hoffer KJ, Philippi G (1978-1982) in their cell membrane theory gave a very lucid hypothesis on cell movement of the endothelium. The stimulus for the endothelial cells begins with an area of cell loss. It is within the defect that the loss of contact between the neighboring cells leads to spreading of the cells, which become quantitatively larger. When through spreading, the cells make contact again, the movement of the cell protoplasm in that direction stops. If the defect is greater, the cells may loose contact on the side opposite the defect. Now the cells lining the secondary gap in cell continuity will respond to this loss of contact by following the first cells. As soon as all the cells are in contact with each other the process stops. This hypothesis therefore explains the findings of the uneven cell size and cell shape (poikilocytosis) that one finds in older patients. Minimal Cell Density The minimum cell density required for corneal clarity is still unknown. It is certain that even after a great reduction of endothelial cells, the cornea is still able to stay clear. Clear corneas were noted with cell counts of 380 (Forstot, 1977), 442 (Binkhorst, 1978) 480 (Kraff, 1978), It would thus appear that cells of 400 to 500 cell/mm2 are adequate to maintain dehydration (Alpar, 1986). On the other hand, corneal decompensation has also been noted at a higher cell count level. Late Corneal Decompensation A presently clear cornea with a low cell count does not really mean that the cornea will remain clear for the rest of the patient’s life. It would only require the subsequent addition of insult, iritis, glaucoma or surgery to precipitate a barely stable cornea into an unstable one, which would lead to decompensation. STEPS TO PREVENT CELL LOSS Prevent IOL Contact From the earlier days it was well known that certain steps led to significant corneal loss. Even the momentary contact of a PMMA lens with the endothelium, led to severe damage to the endothelium. The cells were lifted off (sheared off) the Descemet’s (Kaufmann’s, 1976). Worst( 1984) studies showed that in addition to the contact, movement was also needed. On the other hand, the surface of the natural lens on the endothelium was practically harmless. Contact with the silicone IOL led to a mild loss but contact with a fully hydrated HEMA IOL had hardly any cell loss (Mehta, 1989,92).

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Care with Irrigating Solutions Intracameral and irrigating solutions can also lead to extensive endothelial cell loss. Physiologic salt solution is quite toxic. Ringer lactate is a little better than plain Ringers solution. Balanced salt solution seems to be better, but the ideal solution is BSS plus ( BSS with oxidized glutathione). In the clinical studies comparing BSS to BSS Plus, Klein et al in 1983 found significantly less endothelial cell loss with BSS Plus (15.4%) than with BSS (22.7%) in other patients after ECCE and a posterior chamber implant performed without a viscoelastic. Benson 1981 in a well-designed prospective study found significantly less corneal edema on the first day with BSS plus than with lactated Ringer. There is a paucity of studies comparing BSS with BSS Plus. Kline (1982) showed that there was significantly less loss of endothelial cells using BSS Plus (15.4%), as compared to BSS (22.7%). Despite many studies which show that the endothelial cell count is different, BSS with BSS Plus, one has to clearly appreciate that simple endothelial cell loss does not demonstrate the subtle changes which can be depicted in the early postoperative period. We know that endothelial cell loss continues throughout life and the cornea remains clear by virtue of the endothelial cell reserve, which, with its vital function, maintains deturgescence. Any surgical or non-surgical insult tends to shift the endothelial cell loss curve towards progressive decompensation. (Mishima, 1982). Thus, even a slight increase in the rate of endothelial cell loss can significantly reduce the clarity lifespan of the corneal endothelium. Patients with low endothelial cell densities of the endothelium (diabetics) are known to be more susceptible to surgical stress. Even stresses such as contact lens wear; persistent iritis or glaucoma can lead to corneal decompensation. In cases where the endothelium has already been compromised it would make sense that the most physiological, non-traumatic, endothelial cell viable, irrigating solution should be utilized to give the endothelial cells the maximum chances to survive. The question often asked is why does BSS Plus maintain better structure and functional integrity of intraocular tissues as compared to ordinary BSS or Ringer lactate. This question had been answered by Winkler (1977) who felt that the difference was essentially in the buffer, bicarbonate in BSS Plus, which is the major buffer present in aqueous and effective in the physiological pH range of 6.00 to 8.00. Bicarbonate is also important for normal retinal function (Moorhead, 1979). The citrate-acetate in BSS is effective only at non-physiologic pH levels of 3.6 to 6.2. Citrate may also chelate calcium, which would disrupt endothelial cell functions and barrier functions (Stern, 1981). On the other hand, Ringer lactate lacks a buffer altogether. Other chemical differences between the solutions too play an important role. Glutathione is needed for maintenance of endothelial cell junctions and barrier function and also plays an essential role in endothelial fluid transport (Whikehart DR, 1978). Glucose is an essential energy source for maintenance of aerobic metabolism. It is also used for ATP production for the Na/K pump and NADPH production to reduce glutathione and prevent oxidative damage to endothelial cells. Another factor that is often not taken into account is the time the solution stays in contact with the endothelium. Often one seems to consider the contact time is only

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the surgery time, thinking erroneously, that aqueous replenishes itself virtually immediately. McDermott and Edelhauser in 1988 calculated that it takes over four hours for the aqueous to replace the fluid left in the anterior chamber at the end of surgery. However, an important consideration also is that the aqueous fluid production is nearly always reduced by surgery with a 50 percent reduction being normal, thus, the irrigating solution would remain in the postoperative eye for almost 8 hours. Use Preservative Free Intracameral Solutions Preservative in the solutions can do gross endothelial damage. Especially antioxidants like sodium hydrogen sulfite, bacteriostatic substances like benzalkonium chloride (normally added to solutions as a preservative). Sterilizing solutions like cetrimonium chloride, Hibitane (chlorhexidine), Epinephrine with its preservative, sodium bisuphite, are very toxic, but intracardiac epinephrine (without preservative) at a very low concentration of 0.5 ml in 500 ml of BSS seems to be well tolerated. Use Iced (4o C) Irrigating Solutions Another important consideration when the solution is utilized with phacoemulsification is the temperature of the solution. Although 37o C is considered physiological it would seem more likely that the temperature would be much higher than that especially since the irrigating solution is also utilized to cool the phacoemulsification tip. Accelerated metabolic activity with increased glucose/oxygen consumption and even denaturation of some proteins may occur if the temperature rises just a few degrees above 37o C (Edelhauser, 1987). It is for this reason that the use of cooling solutions has been recommended, by running the tube through an icy bath. Reduced temperatures would reduce the rate of biochemical reactions and reduce inflammation and in addition reduce the risk of a scleral burn from the hot phaco needle especially when hard cataracts are being tackled by phacoemulsification. WHY ENDOTHELIAL CELL LOSS WITH PHACO More often than not, phaco is now done using only topical anesthesia. Sometimes, when the case is predicted to take longer, as when a hard cataract is being done, many surgeons will utilize intracameral 1 percent Xylocard (preservative free Xylocaine utilized by cardiologists). Though Xylocard is considered innocuous the normal corneal endothelial long-term studies still have not shown total safety in corneas, which show some degree of stress. Phacoemulsification is characterized by the use of ultrasound energy coupled with a high quantum of irrigation fluid usage. In addition, a fair amount of movement occurs in the anterior chamber, which is required to prepare the nucleus for removal. Unfortunately, the corneal dome has inadequate space for gymnastics. The surgeon invariably visualizes the critical central area of the cornea, forgetting that the periphery is as important, for injury in the periphery has to heal the same way, namely by cells enlarging and sliding over to close the gap left by the injury. The cells for

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this healing process naturally have to be provided from the adjacent areas and from the center. As far as possible try to minimize multiple entry in and out of the eye, as it will invariably lead to inadvertent corneal touch with grave results. The Surgeon has to Take Special Care During Tunnel Construction At the time of making a corneal tunnel, after dimpling the endothelium at the time of entry, the chamber is well formed and preserved. The problem only occurs at the time of removal of the diamond knife. One needs to remove it without any pressure on the posterior lip to keep the chamber formed. Any undue pressure on the posterior lip will lead to a chamber collapse. Now when the knife is being removed it will rub all over the endothelium. Introduction of the Phaco Tip in the Chamber The corneal periphery is affected every time the surgeon enters the eye, as some level of trauma is induced. Particular care needs to be taken at the time of entry of the phaco instrument. In an effort to enter without touching the iris, the surgeon looses sight of the fact that the phaco will invariably, for a mm or so slide over the inner edge of the cornea, affecting the endothelium. With the Insertion of the Capsulorrhexis Forceps The moment the rhexis forceps is opened, it becomes a race between the instrument entering, and the gradual oozing out of the viscoelastic, leading to a gradual collapse of the chamber which once again needs refilling. In this race, the surgeon tends to turn the rhexis forceps in an inadequate chamber and is likely to touch the endothelium. Doing Peripheral Rhexis in Tight Eyes Similarly, doing rhexis with a forceps in the extreme periphery, care has to be taken that the surgeon concentrating on doing a good rhexis accidentally, does not lift the capsule forceps inadvertently touching the cornea. Time of Insertion of the IOL If forceps are being used, care should be taken, that the chamber is fully distended with viscoelastic substance. The IOL should be carefully inserted. It is better to slightly scrape against the iris rather than scrape the corneal endothelial cells off. If an injector is being utilized, after the tip of the injector enters the corneal tunnel, prior its exit the tip should be slightly deflected down (in a similar maneuver as when the cornea is dimpled for entry during making of the tunnel). This simple maneuver prevents the damage to the endothelial cells.

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The cornea, with either the aqueous or BSS slightly distorts the view, (objects seem slightly bent forwards). Unless the perception of depth with the microscope is exceptional, it may lead the surgeon to miscalculate his or her actual position in the anterior chamber leading to accidental touch. “A panicky surgeon leads to a lost eye.” Nothing panics a surgeon as much as a non-co-operative lens in a phaco surgery. I still remember Professor Fyodorov, the Great Russian Implant specialist being asked at a meeting in Mumbai, as to what he would do if he got into trouble during an IOL insertion, He had replied. “I would sit back, have a shot of Vodka, and then decide what to do“. It is important when a complication occurs, to sit back, reflect on it for a few minutes (not necessarily with Vodka), plan a line of action and only then proceed. It is not the complication, which affects the eye, but often the surgeon who complicates the complication by trying to do everything at the same time, loosing his or her cool and compounding the problematic situation. One must make sure that the IOL does not come into intimate contact with the endothelium in the late postoperative period. Virtually all phaco surgery is now done with corneal tunnels. A properly constructed tunnel gives an excellent result. The problem with a tunnel, which has inadequate length or has a badly designed inner flap, is that it does not seal itself. If the surgeon is unhappy with a tunnel and feels that it may not self-seal, it is better to place a single horizontal mattress or an infinity stitch rather than leaving it untended. A leaking corneal tunnel will lead to a flat chamber and has the propensity for late infection .The fundamental rule should be that a tunnel not sealing on the table will not seal by itself. It must be sutured. Protection of the corneal endothelium has always been a critical requirement for successful phacoemulsification. Protection is particularly important in endotheliallycompromised corneas as in Fuchs’ dystrophy and in all cases where the cell count is inadequate. A good cell count and even more, a proper analysis of the cell configuration is essential prior undertaking phaco. One must be very careful if the second eye of the patient has gone in for decompensation. Some ethnic races have a predilection for decompensation even with, what one would feel, really minimal trauma. In India, Parsis in particular, as a race, do have this problem. ENDOTHELIAL CELL PROTECTION TECHNIQUES IN PHACOEMULSIFICATION Decrease Fluid Input Coupled with Zero Suction It is a well-established fact that prolonged irrigation; coupled with excess aspiration, tends to lead to cell loss. It can be minimized by: (i) altering the irrigation solution used (BSS Plus is the most innocuous), and (ii) usage of zero suction by disconnecting the suction line from the machine. However, zero suction is a problem with the new techniques of chop, which require a firm, hold on the cortical nucleus to be able to chop it successfully. Present day phaco, unless it is being performed on a very hard cataract usually is a short procedure and hence the fluid exchange in the chamber is rarely more than 150 ml.

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Viscoelastic Protection The use of dispersive viscoelastics is supposed to significantly diminish the propensity towards endothelial cell loss (e.g. Viscoat). It must however be clearly understood that the primary aim of viscoelastic substances (VES for short) is that they are space occupying, and maintain the chamber. Steve Arshinoff divided it into two basic groups. An understanding of these groups goes a long way in appreciation of their protection abilities. He divided into: • High viscosity and cohesive ability with zero shear rate and possessing a high molecular weight (examples are Healon, Healon GV, Provisc, Amvisc and Biolon) • Lower viscosity with low cohesive ability but with exceptional dispersive ability, possessing a low molecular weight (examples are Viscoat, Vitrax, HPMC). The high cohesive viscoelastic substances with high viscosity are very useful for the creation and maintenance of space in the anterior chamber. In addition they enable stabilization of the nucleus and the torn capsule during the capsulorrhexis procedure. They can also be used as a tool to separate and dissect tissue like reopening adhesions or reforming a flat chamber. They also act as a inertial energy control when the IOL is shot out of an injector and the viscoelastic substances damp down the speed of silicone unfolding, preventing damage to the tissues, in addition they act as a tamponade for the vitreous in the unlikely event of a capsular rupture. The high cohesive viscoelastic substances have the advantage that they are very easy to remove during the final irrigation or aspiration phase. The high dispersive viscoelastic substances have the advantage that they break down (or disperse) into their components (hence the term dispersive). This group of products forms an adherent layer, which clings onto the endothelium, literally acting as a second skin, and protects the endothelium from the effect of deleterious substances. It is this group which is very useful in performing phacoemulsification on eyes with a poor endothelial cell count. It also has the advantage that it traps the nuclear fragments, preventing them from bouncing off the endothelium during phacoemulsification. The dispersive viscoelastic substances have the disadvantage that at the end of the procedure, they have to be literally, vacuum aspirated. A combination of these substances is now available—Amvisc Plus (Bausch and Lomb). It is said to combine the advantages of both, and is moderately cohesive as well as dispersive. Use of Freezing Solutions Both the viscoelastic as well as the infusion solutions, if used ice-cold are said to have a preservative action on the endothelium (Edelhauser, 1998). In addition the use of freezing solutions also minimizes the incidence of corneal burns from the phaco tips, especially when high ultrasound energies are used with the very hard (suprahard) cataracts.

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Pulse Phaco Usage Diminishing the phaco power by using the pulsed phaco method, and a more sensitive control with better tuning capabilities have both helped to diminish the cell loss. The only problem with pulsed phaco is that it is difficult to really get a good hold on the lens for chopping and thus can only be used after the primary phaco procedure of nuclear chopping is over. A modified version of pulse mode is the Burst mode (the AMO Diplomax and the Alcon Legacy), which, in essence, gives a fixed series of pulses and stops so that the lens can be held. It however has the problem that if attempted, just a bit carelessly, the burst will, in a medium cataract, go all the way through, promptly rupturing the capsule Proper Tip Placement Though newer techniques like tangential or vertical chop have helped further, by decreasing operative time and diminishing intracameral acrobatics, the modern techniques of phacoemulsification depend much more on the ability to properly position the tip to be in an optimal position to hold a lens and chop it down into smaller parts, permitting easy emulsification using negligible ultrasound energy. The problem only comes about if the cataract is very hard. Now the number of times the lens has to be held with bursts of ultrasound power increases. Since the fragments are very hard, the energy required to engulf and emulsify them also increases. Naturally the endothelium exposure to ultrasonic energy will increase. THE ADVENT OF THE CONCEPT OF PHYSICAL ENDOTHELIAL CELL PROTECTION The obvious answer is to protect the endothelium from the deleterious effects of ultrasound, the turbulence of the irrigation fluid, the noxious effects of the irrigating solution and/or intracameral injections (like Xylocard) on the cornea and the accidental touch with the endothelium during intracameral maneuvers. The barrier should be for functional reasons, a physical barrier. The obvious solution in providing a physical protection for the endothelium is the “Hema Hood”. Here a Hema membrane is used to protect the endothelium of the cornea by placing it in direct contact with the endothelium. Thus, in essence, it functions as an endocorneal contact lens. The method devised acts as a physical barrier literally like a corneal endothelial umbrella. Hema Intracameral Endothelial Contact Lens The Hema material used in the Hood has also been used by the author for fashioning Hema soft IOL from 1977 onwards and has been in usage for over 18 years, first as an Iris Clip lens and later as a Disc P/C. It is a proven concept that a soft IOL touching the endothelium of the cornea lead to virtually no deleterious effect. (Packer, 1978, Mehta, 1997,98).

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The Design of the Hema Hood The Hema Hood is designed with a front surface curve of 8.20 mm, of plano power, 9.00 mm total diameter. The central thickness is 0.18 mm. The edge is made with a reverse bevel, which prevents the hood from being dislodged by a stream of BSS from the phaco needle. The Material of the Hema Hood Wohlk (German) soft contact lens material Hexa methyl meth-acrylate with cross-polymers and EGDA Refractive index. 1.44 Elasticity at break 1.40 4.43 × 10-9 Oxygen permeability Hydration: Saline content Water uptake Saline uptake

38.8 percent 62.3 percent 63.6 percent.

Temperature resistance: No change in parameters after boiling for 24 hours Light transmission 400-800 nM Ash content.0.1 mg in 3.00 gm ashed Preparation of the Hood for Usage The endothelial Hood is presented in a metal foil sealed bottle filled with BSS, sterilized by autoclaving, and sealed in a sterile (ETO gas) double pouch. The surgeon takes the bottle on the table utilizing full sterile facilities. The hood is removed from the bottle using a toothless forceps or simply floated out. It is then put in the jaws of a box folder, normally used for folding silicone lenses prior insertion. Using a standard silicone lens insertion forceps the hood is grasped making sure that the entire lens is engulfed in the lips of the holder. It is imperative that the lens be always kept moist. It is then coated with viscoelastic solution prior insertion. Insertion of the Hood The correct time for insertion of the hood in the anterior chamber is after completing the rhexis, finishing the hydrodissection and making sure the nucleus rotates well. The anterior chamber is inflated with viscoelastic (HPMC works best). The Hood is now inserted in a folded stage, held in the holder (Fig. 34.1). Once the lens crosses the ¾ mark of the hood, the forceps is released which permit the hood to unfold (Fig. 34.2). Be sure to release the hood keeping the convex side towards the dome of the cornea. Next, viscoelastic is again injected between the hood and the iris, thus, pushing the hood into intimate contact with the endothelium. The hood sticks by itself to the endothelium. Wait for about 30 seconds, which allows the hood to settle itself, and the phaco procedure may be commenced.

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Fig. 34.1: Hood held in insertion forceps and after folding

Fig. 34.2: Hood being inserted into chamber in folded condition held in forceps

Fig. 34.3: Phacoemulsification with Hood in situ

Fig. 34.4: Phacoemulsification on final fragment with Hood in situ

Phacoemulsification Procedure with the Hood Phaco is allowed to proceed normally with no restriction of technique for the primary phaco or, the subsequently following, I/A or IOL insertion (Figs 34.3 and 4). Any technique can be used, four-quadrant technique to chopping or the newer vertical phacoemulsification. There is no problem if the HEMA hood is accidentally touched, it simply moves and then automatically slides back into position. Even with full irrigation/aspiration, there is no discernible movement of the hood. The IOL can be injected or simply inserted with forceps. The only additional care needed, is at the time of inserting the IOL. When the injector is placed in the tunnel, just prior its exit from the tunnel into the anterior chamber, remember to enter at a slightly steeper angle, tilting the IOL towards the iris to prevent the edge of the hood from being nudged. Again, even if it occurs, the hood will only slide away, like a decentering soft contact lens and then shift back into position smoothly (Fig. 34.5). Removal of the Hood Following Surgery On the completion of the surgery, after the IOL has been inserted, as a last step, take out the Hema Hood. The technique for removal is simplicity itself. Take a

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Fig. 34.5: I/A proceeding with Hood in situ

5.00 ml syringe filled with BSS with a blunt 26 G bent cannula. Insert it into the anterior chamber and squirt at the edge of the Hema hood. As the jet of BSS impacts at the edge of the hood, it dislodges the Hema hood off the endothelium of the cornea. The hood then simply floats onto the iris. Using straight, plain forceps, the Hood is held and simply removed (Fig. 34.6). The hood being a pure Hema material oozes out with no problem. Though the hood is

Fig. 34.6: Hood being removed by holding forceps after separation from cornea

Fig. 34.7: Removed Hood placed on cornea to demonstrate following surgery

supplied as a single use disposable item, it can be washed carefully, placed in BSS, and then reautoclaved (Fig. 34.7). Postsurgical Evaluation The eye is always very quiet. In over 775+ cases done over the last 2 years, no problem has been encountered. The case selection is based on whether it is a hard cataract, which will need more ultrasound time and if the cell counts is poor. It is used as a routine: • If the cell count is 1500 or less. • If the other cornea has suffered decompensation for any reason. • When students are being taught phacoemulsification in a firm or hard cataract as it protects the endothelium very significantly. • In all cases of suprahard cataracts (6+ or over). Endothelial Cell Analysis Analysis of the endothelial cells with the Hema Hood has been carried out in detail in the last 14 months with the Topcon Non-contact Specular Microscope SP-2000P.

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The data is transferred to a Pentium III computer and analyzed with the Topcon “ImageNet” Cell Analysis software which give good, reproducible, stable readings. Initial data would seem to confirm what we had originally conceived. The cell protection ability of the Hood seems very good. To really know if the system works, two independent observers did a series of evaluation of the author’s cases. All cell counts were done with the Topcon Noncontact Specular Microscope SP-2000P. The data being analyzed with the Topcon “ImageNet” Cell Analysis software. The authors’ average cell loss, using the tangential chop for medium cataracts, vertical phacoemulsification for hard cataracts, and the side chop/saddle-hump technique for suprahard cataracts, without the use of the endothelial cell protection device, the Hema Hood were Soft cataracts 0-2.2 percent Medium cataracts 1.2-4.4 percent Hard cataracts 2.4-6.4 percent Suprahard cataracts 5.8-12.3 percent Note The accuracy of the Topcon non-contact endothelial camera technique has a maximum accuracy of (+/-) 2 to 3 percent. With the usage of the Hema hood, three types of cataracts were considered and analyzed: medium density, hard cataracts and suprahard cataracts and their cell counts were done individually. Representative analyses are displayed in Tables 34.1 to 34.3. Table 34.1: Endothelial cell difference in medium density cataracts with the Hema Hood Sr No

Patient

Preop

Postop

Difference

Variation (percentage)

1 2 3 4 5 6 7 8 9 10

HB CG MB DR AS HM RT CD SM DC

3880 2464 2658 3668 3348 4014 4340 3964 2884 4432

3768 2386 2600 3633 3264 3872 4450 3856 2800 4318

112 78 58 35 84 142 10 108 84 114

2.88 3.16 2.18 0.95 2.50 3.53 0.23 2.72 2.9 2.57

Endothelial cell loss as evaluated by a Topcon non-contact endothelial camera: Average Variation = 2.36 percent

Hema Intracameral Contact Lens Endothelial Cell Loss: Average Cell Loss in Phaco with the Hema Hood With any type of lens density, irrespective of the length of the procedure, the cell loss stays in the narrow range of 3 to 5 percent. Subsequently, endothelial cells evaluations were done using the Hood. The cells differences showed that whether a hard or a suprahard cataract was done, the

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Table 34.2: Endothelial cell difference in hard cataracts with the use of the Hema Hood Sr No

Patient

Preop

Postop

1 2 3 4 5 6 7 8

WC RC DS FD TH HR CU YD

3448 2868 4226 3086 5062 3838 3862 4208

3320 2764 4142 3012 4956 3760 3770 4052

Difference 128 104 84 74 106 78 92 158

Variation (percentage) 3.71 3.62 1.98 2.39 2.09 2.03 2.38 3.75

Endothelial cell loss as evaluated by a Topcon non-contact endothelial camera: Average variation = 2.74 percent Table 34.3: Endothelial cell difference in suprahard cataracts with Hema Hood Sr No

Patient

Preop

Postop

Difference

Variation (percentage)

1 2 3 4 5 6 7 8

SH DK NR TD FT RK FN TC

2864 2874 4148 3864 4006 2884 3286 4428

2720 2722 3960 3736 3842 2798 3158 4236

144 154 188 128 164 86 128 192

5.03 5.35 4.53 3.32 4.09 2.98 3.89 4.33

Endothelial cell loss as evaluated by a Topcon non-contact endothelial camera: Average variation = 4.19 percent

difference remained virtually identical. Even in suprahard cataract, which in the authors, own series showed a gross variation, in the Hood series showed a very stable cell count, which, hardly varied. With any type of lens density, irrespective of the length of the procedure, the cell loss stays in the narrow range of 3 to 5 percent. Note The accuracy of the Topcon non-contact endothelial camera technique has a maximum accuracy of (+/-) 2-3 percent. Interestingly in a number of cases of suprahard cataracts after the surgery was over, and the hood was removed a clear demarcation line, almost like a watermark was left. The area protected by the Hood was very clear but a diffuse haze was visible outside the boundaries of the Hood. The haze was there the next day and then gradually faded off. It would thus seem that the Hema protection device is functional. It is particularly useful where the cells are compromised either in quantity or even quality and where the surgeon feels that the endothelium is at risk. It is particularly useful to use when phaco is been done on a case, which has been grafted before. It also makes for an excellent teaching device, as even with prolonged ultrasound power being used in the chamber the endothelium is not at any risk.

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CONCLUSION In the long Odyssey of phaco, the Hema Hood is an effective technique in preserving the vital endothelial cells in the phaco procedure. Usage of the Hood permits phaco even in endothelially compromised corneas, with safety. FURTHER READING 1. Bourne WM, Kaufman HE: Specular microscopy of human corneal endothelium. Am J Ophthalmol 81: 219-33, 1975. 2. Glaser JS, Savino PJ, Sumers KD et al: The photostress recovery test in the clinical assessment of visual function. Am J Ophthalmol 83: 255-260, 1977. 3. Glasser DB, Matsuda M, Ellis JG et al: Effects of intraocular irrigation solution on the corneal endothelium following in-vivo anterior chamber irrigation. Accepted for publication. Am J Ophthalmol 1985. 4. Alpar JJ: Endothelium protection using Healon, serum or air in cataract extraction and intraocular lens implantation. J of Ocular Therapy & Surgery 3(5): 229-33, 1984. 5. Mishima S: Clinical investigations on the corneal endothelium, XXXVIII Edward Jackson Memorial Lecture. Am J Ophthalmol 1982;93: 1-29. 6. Winkler BS, Simson V, Benner J: Importance of bicarbonate in retinal function. Invest Ophthalmol Vis Sci 167: 766-68, 1977. 7. Moorhead LC, Redburn DA, Merritt J et al: The effects of intravitreal irrigation during vitrectomy on the electroretinogram. Am J Ophthalmol 88: 239-245, 1977. 8. Whikehart DR, Edelhauser HF: Glutathione in rabbit corneal endothelia—the effects of selected perfusion fluids. Invest Ophthalmol Vis Sci 17: 455-64, 1978. 9. McDermott ML, Edelhauser HF, Hack HM et al: Ophthalmic irrigants—a current review and update. Ophthalmic Surg 19: 724-33, 1988. 10. Edelhauser HF, Gonnering R, Van Horn DL: Intraocular irrigating solutions—a comparative study of BSS Plus and lactated Ringer’s solutions. Arch Ophthalmol 96: 516-20, 1978 11. Edelhauser HF, Van Horn DL, Schultz RO et al: Comparative toxicity of intraocular irrigating solutions on the corneal endothelium. Am J Ophthalmol 81: 473-81, 1976. 12. Edelhauser HF, Van Horn DL,Hynduiuk RA et al: Intraocular irrigating solutions—their effect on the corneal endothelium. Arch Ophthalmol 93: 648-57, 1975 13. Edelhauser HF, Rosenfeld SI, Waltman SR et al: Discussion of comparison of intraocular irrigating solutions in pars plana vitrectomy. Ophthalmology 93: 114-15, 1986. 14. Edelhauser HF: Intraocular irrigating solutions. In Lamberts DW, Potter DE (Eds): Clinical Ophthalmic Pharmacology. Little, Brown and Co: Boston, 431-44, 1987. 15. Binkhorst CD: Five hundred planned extracapsular extractions with irido-capsular and iris clip lens implantation in senile cataract. In Boyd BF (Ed): Highlights of Ophthalmology, 20: 267-308, 1978-1979. 16. Cotlier E: The cornea. In Moses RA (Ed): Adler’s Physiology of the Eye. CV Mosby: St. Louis, 35, 1970. 17. Forstor SL, Blackwell WL, Jaffe NS et al: The effect of intraocular lens implantation on the corneal endothelium. Trans Am Acad Ophthalmol Otolaryngol 83: 195-203, 1977. 18. Glasser DB, Matsuda M, Ellis JG et al: Effects of intraocular irrigation solution on the corneal endothelium following in-vivo anterior chamber irrigation. Accepted for publication. Am J Ophthalmol, 1985. 19. Hoffer KJ, Philippi G: A cell membrane theory of endothelial repair and vertical cell loss after cataract surgery. Am Intra-Ocular Implant Soc J 4: 18, 1978. 20. Maurice DM: Cellular membrane activity in the corneal endothelium of the intact eye. Experientia 24: 1094-95, 1968. 21. Maurice DM: The location of the fluid pump in the cornea. J Physiol 43: 221, 1972. 22. Blatt HL, Rao GN, Aquavella JV: Endothelial cell denstiy in relation to morphology. Invest Ophthalmol 18:856, 1979. 23. Eisner G: Biomicroscopy of the Peripheral Fundus: An Atlas and Textbook, Springer: Heidelberg, 1973. 24. Sherrard ES, Novakovic P, Speedwell Z: Age-related changes of the corneal endothelium and stroma as seen in vivo by specular microscopy. Eye 1: 197, 1987. 25. Tripathi RC, Tripathi BJ: Functional anatomy of the anterior chamber angle, In Duane TD, Jaeger EA (Eds): Biomedical Foundations of Ophthalmology Lippincott: Philadephia, 10: 1, 1982. 26. Tripathi RC, Tripathi BJ: Anatomy of the human eye, orbit and adnexa. In Davson H (Ed): The Eye, (3rd ed) Academy Press: London, 40:157, 1984.

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27. Mehta KR, Sathe SM, Karyekar SD: Intra-Ocular Lens Manufacturing Quality Assessment, Xth Congress APAO Soc Proc 1:419-20,1985. 28. Mehta KR: Progressive corneal endothelial decompensation—extended wear contact lenses with aphakia. All India Ophthl Soc Proc 109-14,1989. 29. Mehta KR: The new clover leaf stabiliser (CLS) for the safe and effective insertion of posterior chamber IOL over a broken capsular face. All India Ophthl Soc Proc 251-53,1995. 30. Mehta KR, Sathe SM, Karyekar SD: New soft posterior chamber implant. Xth Congress APAO Soc Proc 1:421-23, 1985. 31. Mehta KR: When not to do an anterior chamber implant. All India Ophthl Soc Proc 164-65,1986. 32. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in paediatric cataracts. All India Ophthl Soc Proc 207-10,1995. 33. Mehta KR: Tangential chop (MTC Technique) for phacoemulsification. All India Ophthl Soc Proc (Chandigarh) 1996. 34. Mehta KR: Combined astigmatic annular keratotomy and phaco—a corneal topographic analytical technique. All India Ophthl Soc Proc (Chandigarh) 1996. 35. Mehta KR: Hema intracameral Hood—corneal turbulence control in phaco. All India Ophthl Soc Proc (Chandigarh) 1996. 36. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997. 37. Mehta KR: Newer techniques for eye camp safe phaco techniques. APIIA Conference, 1997. 38. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 39. Mehta KR: Effective endothelial cell protection during phacoemulsification with Hema intracameral contact lens (HICL). Proc of SAARC Conference, Nepal, 1994. 40. Mehta KR: Methylcellulose induced sterile endophthalmitis following phacoemulsification. Proc of SAARC Conference, Nepal, 1994. 41. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular famage. Proc of SAARC Conference, Nepal, 1994

I Howard Fine Richard S Hoffman

Phacoemulsification in the Presence of Pseudoexfoliation: Challenges and Options

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INTRODUCTION Cataract surgery in the presence of pseudoexfoliation of the lens presents surgeons with unusual challenges. In addition to a higher incidence of glaucoma, these patients have loss of zonular integrity occasionally associated with lens subluxation and pupils that dilate poorly. Although the use of phacoemulsification in experienced hands has resulted in a low incidence of intraoperative and postoperative complications such as zonular dialysis, capsule tears, vitreous loss, and IOL decentration;1 special care should still be exercised when performing cataract surgery in these patients. Improvements in phacoemulsification technology, technique, and new capsular supporting rings will ultimately enable these patients to undergo cataract surgery with even fewer complications. Technique Glaucoma Poorly controlled glaucoma with concomitant cataract and pseudoexfoliation is best managed by a glaucoma triple procedure. We prefer the utilization of a limbal conjunctival incision without vertical releasing incisions and a self-sealing scleral tunnel incision (without vertical releasing incisions) located superiorly through which phacoemulsification is performed. A Crozafon-De Laage Punch (Moria # 18069) is used to disrupt the posterior corneal lip creating a fistula which usually results in a diffuse shallow bleb that filters posteriorly. The conjunctival incision is sutured to the limbus at the conclusion of the procedure. Although this is our preferred method, any combined technique can be used with or without the use of antimetabolites.

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Figs 35.1A to C: (A) Small pupil with Beehler pupil dilator inserted through temporal clear corneal incision. (B) Temporal iris is engaged with mounted hook on undersurface of instrument and retracted while the dilator is opened to stretch the pupil at four points 360 degrees. (C) Appearance of pupil following mechanical dilation

For patients with glaucoma who do not need filtration surgery at the time of cataract surgery, we prefer our usual clear corneal incision from the temporal periphery. This allows the entire procedure to take place through avascular tissue and does not prejudice future filtration surgery in a superior location. Small Pupils The small pupil can be managed in a variety of ways including sector iridectomy, iris hooks, iris rings, and pupillary stretching with or without the use of multiple half-width sphincterotomies.2 At present, we find the Beehler Pupil Dilator (Moria # 19009) to be uniformly applicable in the presence of small pupils. It usually stretches the pupil to 6 to 7 mm while creating tiny microsphincterotomies circumferentially around the pupil (Figs 35.1A to C). The pupil can then be mechanically reduced at the end of the procedure with a Lester hook supplemented with an intraocular miotic. Pupils enlarged in this manner maintain a good cosmetic appearance and an ability to react to light but may require miotic drops for some time following cataract surgery to avoid synechiae to the capsulorrhexis margin. Capsulorrhexis Weak zonules present particularly challenging situations during phacoemulsification. Of utmost importance is not to challenge the integrity of the zonules by overpressurizing the eye. This can occur following peri- or retrobulbar injection with digital or Honan pressure, overexpanding the anterior chamber with viscoelastic

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prior to capsulotomy, or utilizing an excessively high bottle height during phacoemulsification. Due to the lack of zonular integrity, it is frequently difficult to actually perforate the capsule to begin a capsulorrhexis. We use a pinch-type forceps such as the Kershner Capsulorrhexis Cystotome Forceps (Rhein Medical 05-2320) or the Rhein Capsulorrhexis Cystotome Forceps (Rhein Medical 05-2326) which allow one to grasp the capsule to start the tear rather than beginning the capsulotomy with a perforation by downward pressure on the lens. This is especially important in fibrosed capsules which cannot be perforated by a needle. When one purchases the capsule with a pinch and tears it, the tear will commence at the edge of the fibrosis, usually at the pupillary margin. During the capsulotomy, special care and attention are required because traction on the capsule can unzip weakened zonules. If there are areas of missing zonules, centripetal traction on the capsular flap may result in further damage to the adjacent weakened zonules. Techniques of two-handed capsulotomy using tangential forces as described by Neuhann3 are excellent adjunctive techniques in situations with loose zonules. After the capsulotomy has been started, the capsular flap is stabilized with the forceps through the main incision while a second instrument such as a bifurcated spatula is introduced through the side port incision. Slight backward traction is placed on the flap with the forceps while the second instrument directly advances the torn edge in a tangential manner. Capsulorrhexis size is extremely important in patients with pseudoexfoliation. Ideal capsulorrhexis size is felt to be 5.5 to 6.0 mm or larger in routine patients.4 We believe it should be at least 6.0 mm in pseudoexfoliation cases since a larger capsulorrhexis leaves a smaller burden of lens epithelial cells postoperatively than smaller capsulorrhexes. Residual lens epithelial cells participate in metaplasia and extracellular matrix deposition ultimately resulting in capsular fibrosis.5 Patients with pseudoexfoliation are particularly susceptible to marked shrinkage of the rhexis because the strong forces of fibrosis and contraction are unopposed by strong zonular traction.6 Thus a larger capsulorrhexis should decrease the incidence of symptomatic capsule contraction by decreasing the number of epithelial cells able to participate in the fibrosis process and allow for a larger final rhexis diameter once capsule contraction has ultimately ceased to progress. Hydrodissection and Hydrodelineation Cortical cleaving hydrodissection7 requires extremely careful maneuvers especially when one decompresses the bag after having performed the posterior fluid wave. It is important to do this very gently and to utilize multiple locations for partial cortical cleaving hydrodissection injections with gentle central lens decompression. This should alleviate the chances of depressing the lens with excessive forces which would tear zonules. Hydrodelineation is a useful technique in pseudoexfoliation since it produces an epinuclear shell as an important added safeguard. During both hydrodissection

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and hydrodelineation, it is wise to keep the cannula in a position slightly depressing the posterior lip of the incision. This will ensure easy egress out of the eye for either viscoelastic or fluid should one overinflate the spaces with balanced salt solution (BSS). Phacoemulsification One must use extreme caution during Fig. 35.2: Following formation of a vertical groove manipulation of the lens so as to not tear in the meridian of the incision, a groove perpenzonules. Two-handed rotations of the lens dicular to the first is formed without rotating the by moving the phaco probe laterally and with nucleus are wise since the forces can be lens a rotational movement truly tangential and can be divided by utilizing opposite sides of the same meridian. Grooving also requires special care since there is a tendency to put posterior pressure on the nucleus. High cavitation tips such as the Kelman tip on the Alcon system 20,000 Legacy are a great advantage since they can obliterate nuclear material in advance of the tip without exerting forces on the lens or the lens zonules. The particular configuration of the Kelman tip allows for a variation of the Gimbel “phaco sweep” procedure8 where the initial groove can be formed and then, without rotating the lens, a lateral and rotational motion of the phaco probe grooves in a lateral direction (Fig. 35.2). One may also help stabilize the nucleus during grooving. We find it best not to perform downslope sculpting because nudging the nucleus in the direction in which one is sculpting can put unnecessary traction on the zonules in the subincisional area. If the nucleus is going to be stabilized at all, it can be stabilized through the side port with a second instrument. In addition to stabilization, one can actually push the nucleus toward the phaco tip to maximize the efficiency of the tip and at the same time elevate the lens slightly. For lens cracking, we recommend non-rotational cracking as described by Fine, Maloney, and Dillman.9 This appears to be the least traumatic method for cracking the nucleus and dismantling it into quadrants that are easy to mobilize. Chopping techniques are also useful for dismantling the nucleus while placing minimal stress on the zonular apparatus. In both techniques, the epinuclear shell participates in stabilization of the nucleus, and is useful during the mobilization of the four quadrants because all of the phaco and mechanical forces can be confined within the epinuclear space reducing stress on the zonules as well as the capsule. Cortical aspiration represents the biggest threat to the zonules during phacoemulsification of cataracts in pseudoexfoliation patients because the greatest amount of traction can be placed on the zonules during this step of the procedure. Prior use of cortical cleaving hydrodissection is important in reducing traction on zonules and facilitating removal, of most if not all, of the cortex during flipping and evacuation

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of the epinuclear shell. Viscodissection to separate cortex from the capsule can also be used to assist in cortex removal or used to isolate segments of nucleus. In general, we recommend that cortical clean-up not to be performed in these cases until after implantation of the IOL. Aspiration of residual cortex is safer after the lens has been implanted due to stabilization of the capsular bag by the implant. In the presence of pseudoexfoliation, we usually utilize a foldable lens with PMMA Fig. 35.3: Tangential stripping of cortical material rather than centripetal stripping maximizes forces haptics sized for bag placement. The optic on a few cortical/capsular connections at a time size is 6.0 mm to allow for an extra margin of safety should mild lens decentration develops. The overall lens diameter is 12.0 to 12.5 mm utilizing PMMA haptics to increase haptic resistance and attempt to prevent capsule contraction and lens decentration. We also recommend tangential traction on the cortex with the I/A tip rather than stripping centrally in order to maximize forces on a few cortical or capsular connections at a time (Fig. 35.3). If there are areas of zonular dehiscence, it is important to strip tangentially toward the dehiscence rather than away from it since stripping away from the area of dehiscence would localize forces on weakened zonules which might lead to unzipping of the zonular dehiscence. Capsular Ring The newest and most important adjunctive therapy in addressing cataracts with pseudoexfoliation has been the use of a capsular ring (Morcher/Kapuzinerweg 12, D-70374 Stuttgart, Germany*) as described by Witschel and Legler (“New Approaches to Zonular Cases: The Capsular Ring, “Audiovisual Journal of Cataract and Implant Surgery 1993; Vol. IX, issue 4) and Cionni and Osher.10 The endocapsular ring is a polymethylmethacrylate ring with expanded ends which contain positioning holes. The ring comes in two sizes: 10 mm (type 14) for routine cases, and 12 mm (type 14A) for high myopes. When placed within the capsular bag, which is approximately 10 mm in diameter, the ring keeps the bag on stretch and provides several advantages. It prevents concentration of forces on individual zonules by distributing all forces applied to any point on the capsulorrhexis to the entire zonular apparatus. It also keeps the bag on stretch throughout the procedure, allowing for greater safety during all intraocular manipulations. Finally, the continuous pressure of the ring against the capsular fornices acts to bolster any residual zonular traction on the capsule and counter the force of constriction following metaplasia and fibrosis of the capsulorrhexis. * The endocapsular ring is not currently an FDA approved device

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Figs 35.4A to D: Capsular ring insertion. (A) Following capsulorrhexis and prior to cortical cleaving hydrodissection, the capsular ring is inserted through the clear corneal incision with a forceps. The leading eyelet is placed under the capsulorrhexis into the capsular fornix. (B) Once the ring is inserted to the point that the trailing eyelet has reached the incision, a Lester hook is placed in the trailing eyelet while a second Lester hook is placed through the paracentesis. (C) The right-handed Lester hook then inserts the ring further as it enters the anterior chamber while the second instrument helps guide the capsular ring. (D) As the trailing eyelet reaches the edge of the capsulorrhexis, the right-handed Lester hook is rotated clockwise 90 degrees in order to disengage the eyelet from the hook. The inherent tension of the ring will place the trailing end in the capsular fornix

We have found it best to place the ring in the bag immediately after the capsulorrhexis is completed. The ring is slipped into the incision and fed under the rhexis with a forceps while the second hand guides it with a Lester hook through the side port incision (Figs 35.4A to D). Once the ring is in place, cortical cleaving hydrodissection is performed followed by hydrodelineation, and then the remainder of the procedure can be done utilizing many of the guidelines listed above. Although cortical cleaving hydrodissection may have been performed, the endocapsular ring holds much of the cortex pressed up against the capsular fornices requiring an additional amount of force to remove the cortex with the irrigation/aspiration handpiece. Despite this, there is a great deal of more safety during the procedure because of the equal distribution of forces by the ring and stabilization of the capsular bag. The safety of a plate haptic lens in the presence of an endocapsular ring is in question due to the outward force of the ring. The ring may allow for decentration of the plate haptic IOL because it continues to keep the bag in a highly expanded state. In addition, YAG laser capsulotomy, which may be followed by tears of the posterior capsule out to the equator, could allow a plate haptic lens to drop into the vitreous cavity since older style lenses are not fixated by the capsule.11 It is possible that the newer designed

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plate haptic lenses with fenestrations or half-haptics will be safer in the presence of an endocapsular ring since they have been shown to fixate to the capsular bag (DJ Apple, MD, “Enhancement of Silicone Plate IOL Fixation by the Use of Positioning Holes in the Lens Haptic,” American Society of Cataract and Refractive Surgery Symposium, June, 1996 and N Mamalis, MD, “Comparison of Silicone Plate Haptic IOL Models AA-4203 and AA4203F in a Rabbit Model,” American Society of Cataract and Refractive Surgery Symposium, June, 1996).

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Fig. 35.5: Appearance of eye following phacoemulsification, lens insertion, and mechanical and pharmacologic pupil constriction

CONCLUSION Phacoemulsification in the presence of pseudoexfoliation presents surgeons with the possibility of many complications which are less likely to occur in the absence of pseudoexfoliation. Specialized techniques are available which should allow the surgeon to both avoid and cope with the various intraoperative difficulties which may become manifest during cataract surgery in these patients. One of the newest devices available to assist in managing these cases is the endocapsular ring. It offers the potential benefits of fewer intra- and postoperative complications by means of capsular stabilization. Future studies will ultimately determine all of the benefits and indications of the endocapsular ring. REFERENCES 1. Osher RH, Cionni RJ, Gimbel HV et al: Cataract surgery in patients with pseudoexfoliation syndrome. Eur J Implant Ref Surg 5:46-50, 1993. 2. Fine IH: Phacoemulsification in the presence of a small pupil. In: Steinert RF (Ed): Cataract Surgery: Technique, Complications and Management. WB Saunders: Philadelphia, 199-208, 1995. 3. Neuhann TF: Capsulorrhexis. In Steinert RF (Ed): Cataract Surgery: Technique, Complications and Management WB Saunders: Philadelphia, 134-42, 1995. 4. Joo CK, Shin JA, Kim JH: Capsular opening contraction after continuous curvilinear capsulorrhexis and intraocular lens implantation. J Cataract Refract Surg 22:585-90, 1996. 5. Ishibashi T, Araki H, Sugai S et al: Anterior capsule opacification in monkey eyes with posterior chamber intraocular lenses. Arch Ophthalmol 111: 1685-90, 1993. 6. Davison JA: Capsule contraction syndrome. J Cataract Refract Surg 19:582-89, 1993. 7. Fine IH: Cortical cleaving hydrodissection. J Cataract Refract Surg 18:508-12, 1992. 8. Gimbel HV, Chin PK: Phaco sweep. J Cataract Refract Surg 21:493-503, 1995. 9. Fine IH, Maloney WF, Dillman DM: Crack and flip phacoemulsification technique. J Cataract Refract Surg 19:797-802, 1993. 10. Cionni RJ, Osher RH: Endocapsular ring approach to the subluxed cataractous lens. J Cataract Refract Surg 21: 245-49, 1995. 11. Levy JH, Pisacano AM, Anello RD: Displacement of bag-placed hydrogel lenses into the various following neodymium: YAG laser capsulotomy. J Cataract Refract Surg 16: 563-66, 1990.

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I Howard Fine Richard S Hoffman

Phacoemulsification in Severe Chronic Obstructive Pulmonary Disease

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INTRODUCTION The transition from extracapsular cataract extraction (ECCE) to phacoemulsification has greatly reduced the intraoperative risks of performing cataract surgery in patients with chronic obstructive pulmonary disease (COPD). Faster operating times and small 3-mm self-sealing incisions have made cataract surgery more comfortable and safer in these patients. Despite this, there are special considerations which should be made in COPD patients to assist in the best possible outcomes. This is especially true when cataract surgery may be prolonged because of concomitant glaucoma, corneal, or vitreous surgery. The two main obstacles to overcome when performing cataract surgery in COPD patients are coughing and intolerance to the fully supine position. Cough Most patients may undergo surgery under topical anesthesia; however, patients with severe COPD who may be prone to frequent coughing might benefit from local anesthesia in order to reduce the risk of choroidal hemorrhage or effusion. In most instances, coughing during phacoemulsification is not problematic since surgical instruments can be removed from the eye at the first hint of a cough. The small incision should self-seal maintaining the integrity of the intraocular contents. In most instances of coughing, it may be preferable to leave the phacoemulsification probe in the eye in foot position number 1 in order to maintain pressure within the globe. The forehead should be supported with the second hand reducing the risks from excessive head movement.

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Preoperative medications can assist in cough elimination or suppression. Bronchodilators administered by nebulizer or aerosol treatments help patients with severe COPD clear bronchial secretions long enough to eliminate coughing during surgery. Albuterol 2.5 mg (0.5 ml of the 0.5% solution diluted with 2.5 cc sterile normal saline) delivered over 10 minutes by nebulizer or two puffs of albuterol inhalation aerosol administered 30 minutes prior to surgery have been extremely effective in alleviating coughing in even the most recalcitrant COPD patient. Cough suppressants in the form of dextromethorphan cough lozenges and cough syrup are also extremely helpful. If the need arises to suppress the cough reflex during the procedure, fentanyl 25 to 50 µg or lidocaine 20 mg can be administered intravenously. Oxygen Therapy Oxygen administration by nasal cannula is employed during surgery for all cataract patients. In patients with COPD, low flow oxygen administration at 1 to 3 liters per minute is the usual dose. Oxygen flows higher than this are feared to place the patient at risk for worsening hypercapnia however, we do not feel this is a problem for the short duration of increased oxygen administration which may occur during phacoemulsification. Positioning for Surgery Most patients with COPD can undergo surgery lying flat on an operating table. Positioning the patient with pillows under the legs and shoulders with the bed in a slight Trendelenburg position is helpful in maintaining patient comfort by simulating the sitting position. There are many patients with severe COPD who find it almost impossible to assume a supine position. It is possible to perform phacoemulsification in a patient who is not fully supine. Rimmer and Miller1 previously reported on a case of phacoemulsification performed in the standing position. They used loupe magnification and headlamp illumination in order to remove a cataract in a patient unable to recline because of myotonic dystrophy and advanced interstitial lung disease. Other surgeons have also reported performing standing phacoemulsification using the operating microscope in patients who were unable to recline fully.2,3 Unfortunately, positioning a patient in a seated or partially reclined position creates an abnormal angle of approach for the operating room microscope which results difficulty in focusing and manipulating tissues and instruments intraocularly. Also, with the head in an upright position, gravity causes shallowing of the anterior chamber moving both the posterior capsule and the vitreous forward. This creates a greater risk for damaging the cornea and the posterior capsule during the procedure. We have attempted to address the problems inherent in approaching these patients surgically by altering a waiting room chair to enable these patients to remain

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Fig. 36.1: Waiting room chair altered by placing back cushion of chair on adjustable brackets. Legs shortened and head rest clamp attached to back of chair. Spindle for counterbalance weight attached to base. Chair in upright position

Fig. 36.2: Front view of reclined chair with counterbalance weight between front legs

in an upright seated position and place their head back so that surgery can be performed in the usual head position obtained in the supine position on an operating room table (Figs 36.1 to 36.3). We have operated approximately 10 patients in this manner, all of them without complication or difficulty and in some cases with somewhat greater ease for the surgeon because there was no limitation in access to the head. In each instance, patients were free of some of the congestive and anoxic symptoms they had in a supine position (Fig. 36.4).

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Fig. 36.3: Side view of reclined chair

Fig. 36.4: Patient with chronic obstructive pulmonary disease reclining comfortably in chair prior to undergoing cataract surgery. Legs resting on foot rest

There are occasional COPD patients who are also unable to tolerate a full face surgical drape because of claustrophobia. We have found it useful in these patients to perform a full face preparation and use only an aperture drape around the eye; avoiding draping the rest of the face so that the sensation of being closed in was eliminated. Phacoemulsification Phacoemulsification in COPD patients is performed the same as in any other patient. The use of cracking or chopping techniques within an epinuclear shell allows for added safety should the patient move or cough. Special attention should be directed at removing all viscoelastic material at the conclusion of the procedure since the treatment of postoperative pressure increases is limited by the intolerance of COPD patients to many glaucoma medications. Non-selective beta-blockers should be avoided and even selective beta-blockers should be used cautiously since many severe COPD patients will crossreact to beta 1-blockers, worsening their respiratory function.

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CONCLUSION Cataract surgery continues to undergo improvements and refinements making it safer and faster. Although most patients with COPD can undergo phacoemulsification without regards to their respiratory disease, patients with severe pulmonary disease often present challenges to the cataract surgeon. Coughing will usually present itself as more of a nuisance than a threat to surgical outcome now that incision architecture has allowed for small self-sealing wounds. Despite this, there are measures that can be taken preoperatively to help reduce the incidence of coughing allowing for safer uninterrupted phacoemulsification. Probably the greatest obstacle and challenge for performing surgery in these patients are those individuals who are unable to fully recline for the operation. Phacoemulsification can be performed in the standing position to accommodate patients who are intolerant to the supine position, however we feel that new surgical tables and/or surgical chairs will allow patients with severe COPD to undergo phacoemulsification under safer and more comfortable conditions in the future. REFERENCES 1. Rimmer S, Miller KM: Phacoemulsification in the standing position with loupe magnification and head lamp illumination. J Cataract Refract Surg 20:353-54, 1994. 2. Hunter LH: Standing while performing phacoemulsification. J Cataract Refract Surg 21:111, 1995. 3. Liu C: Phacoemulsification in a patient with torticollis. J Cataract Refract Surg 21:364, 1995.

Keiki R Mehta

The Prevention of Complications and their Management in Phacoemulsification

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INTRODUCTION Phacoemulsification is an excellent procedure however, it needs to be done with care and caution. In the hands of a skilled surgeon, phacoemulsification can give exceptional vision, rapid rehabilitation, in a virtually painless procedure. For the less experienced surgeon, if the selection of cases is not appropriate, there is always a possibility of having problems. In phacoemulsification every single step commencing from the preparation and positioning of the instrument, to the proper construction of the corneal tunnel, the capsulorrhexis, and the completion of the procedure, have to be accurate and well completed. A mistake in one step will snowball into problems, which will complicate the steps to follow. In this chapter, let us take problems as they arise. Some of them may seem very small and steps to prevent them would seem to be insignificant, but experience has taught that the smallest steps, if ignored can precipitate situations, which are best avoided. PREVENTIVE ASPECTS PRIOR COMMENCING PHACOEMULSIFICATION Positioning of the Patient Proper positioning of the patient is very important as it permits stability with adequate access to the eye. The brow and the chin of the patient should be on the same horizontal plane and at right angles to the operating microscope. It is important to keep a number of small rubber pillows, of different thickness, (1/2 inch, 1 inch, 2 inch, 3 inch, 4 inch) which can be added to get the best possible position of the forehead. It is important that a rubber ring be inserted under the head on the

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final rubber pillow, which will prevent the rolling of the head during surgery stabilizing it further. The premade trough pillows (a section cut into them to fit the head) are quite inadequate. Either they are too large, permitting excessive rotation, or too small, in which case the head sits on the edges and does not fit into the groove, making it very unstable. Checking the Intraocular Pressure It is mandatory prior commencing surgery, whether a retrobulbar, a peribulbar, or topical anesthesia is being utilized, that the intraocular pressure (IOP) be checked with a Schiotz tonometer on the table. Many surgeons will check the pressure digitally (using the digits of two fingers) after giving a retrobulbar, or a peribulbar block. The block merely relaxes the muscles and a digital check-up merely indicates the softness of the retro-orbital tissues and does not reflect the softness of the eye. Immediate preoperative checking IOP with a Schiotz tonometer routinely is important. Often surprises will occur when an eye, thought to be soft digitally, will turn out to have a high pressure with the tonometer. In topical anesthesia, what must be remembered is that the eyes are being maximally dilated, using a combination of NeoSynephrine 5 percent with homatropine 2 percent. Thus, there is always the chance of an angle-closure glaucoma (ACG) developing, even more so considering that the cataract, being advanced, is likely to have swollen. A pressure up to 21 mm Hg would be taken as acceptable, while the surgery may need to be put off for some time and an effort made to reduce the IOP by I/V Mannitol or pressure with a Honan’s balloon or Buy’s bag or the balancing balls. Ideal pressure for phacoemulsification is 15 mm Hg or below. Doing phaco surgery with a high IOP is asking for trouble. The chamber will tend to collapse and will remain shallow. There is always the likelihood of endothelial damage. The chances of capsular break are significantly increased, and God forbid, if the capsule breaks, vitreous loss is virtually inevitable. Oxygen or Fresh Air under the Drapes It makes sense to use a digital oxygen saturation monitor in all cases. Fresh air provided under the drapes (fresh air, since oxygen is not truly required, though preferable) washes out the carbon dioxide, which induces air hunger and makes a patient extremely restive. Patients, in the older age group, already have compromised pulmonary function and go into oxygen deprivation extremely quickly. The presence of fresh air whistling under the nose gives the patient a comfortable feeling. If the surgery is being done under topical anesthesia, adequate oxygenation is vitally important for a peaceful patient, which would lead to peaceful surgery by a peaceful surgeon. The ideal technique of introducing the air/oxygen is by using soft silicone nasal prongs, which enables the air to whistle comfortably in the nostrils. The plastic tube should be fixed so it does not move and irritate the patient during surgery. The ideal technique is to loop the plastic tube around the ears and then fix them under the chin. Fixed in this manner, the tube remains stable no matter how the patient moves. This particular technique is termed as the Santa Barbara method.

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Placement of the Lid Retractor The lid retractor should be able to properly open the eye to achieve good access without causing any discomfort. Essentially retractors can be divided into two categories. • Fixed retractors can be opened and fixed at a required lid retraction or opening, using a ratchet arrangement or a screw attachment. The advantage of the fixed retractors is that the quantum of the opening can be varied as per requirement. On the other hand, the disadvantage is that the patient often tries to fight the offending retractor, which causes pain, leads to an uncooperative patient. • Spring retractors utilize a spring mechanism to keep the eye open. The spring retractors only open to the level at which the tension of the lid is offset by the tensile strength of the spring. Thus the quantum pf opening is dependent on the tension of the lids vis-a-vis the spring elasticity. The big advantage is that as the patient tries to forcibly close the eye the spring retractor automatically closes and then reopens. After some time of this closing and opening cycles, the orbicularis tires and the eye remains open. However, the advantage is that the patient is comfortable and the cooperation of the patient is assured. Aspiration of Excess Fluid In a deep-set eye or in one that has prominent bony configuration the BSS and secretions tends to accumulate in the eye and reflect like a mirror back into the operating microscope literally blurring the surgeon’s vision. It is thus important that the fluid be aspirated or drained off. There are many types of drains available. Merocell is a close mesh plastic which allows the fluid to flow out of the eye. Builtin aspirator is a benefit with retractors. Usually the suction line is in-built and the openings in the tines of the retractors suffice to suck out the excess BSS and secretion from the eye. This is an ideal type and is to be recommended. Connect the aspirating retractor to a small suction unit. Usually the suction units available in the hospital are much too powerful and tend to suck in not only the fluid but also the conjunctiva. A small gentle dental suction unit that has a suction of 2 to 4 mm Hg is ideal. This little suction unit should be connected via a silicone, autoclavable tube to the aspirating retractor or alternatively, a small hand suction tip so the assistant can do the suction. It keeps the field dry, prevents Merocell or cotton swabs from being used continuously near the fornices. This continuous swabbing predispose to redness and small subconjunctival hemorrhages the next day. It also increases the possibility of accidental pressure on the eye, especially after the attendant becomes inattentive, after long list of surgical cases, typically at the end of the day. COMPLICATIONS AT VARIOUS PHASES OF PHACOEMULSIFICATION SURGERY The incision is the most important part of the phacoemulsification surgery.

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Clear Corneal Incision To be a self-sealing incision, the tunnel must be of an adequate length. The incision at the entry point on the cornea and the exit point at the Descemet’s membrane should be a straight line if the valve is to really function well. The ideal instrument is a diamond knife where there is a differential bevel between the front and the back. This type of a diamond knife, conceived by Dr Fine, made by Rheim, called a 3D blade, gives almost perfect tunnel formation time after time. However, a metal keratome or knife would also work well but would need a lot more experience to achieve perfect tunnels. The diamond knife does it effortlessly. Many surgeons prefer to use a round beveled blade to dissect a pocket, and then use a 15-degree sharp knife to enter into the anterior chamber. Though in the hands of an expert this technique would seem to be adequate, its ability to do consistent corneal tunnels is limited. With phacoemulsification, it is important that the width of the incision must exactly mimic the width of the phaco tip used. Some machines require 3.00 mm for the phaco tip introduction in the anterior chamber while in others 2.8 mm may be ideal. In the author’s machine, an Alcon Legacy with the 0.9 mm diameter tips, a 2.8 mm incision is required. If incision is too narrow, it is difficult to insert the phaco tip, which is liable to brush against the Descemet’s and even detach the Descemet’s is as the phaco tip enters the anterior chamber. The other problem being that if it is too narrow the sleeve tends to get compressed in the lips of the tunnel, choking off the inflow of irrigating solution. A phaco tip remains cool by the flow of irrigating solution over the phaco tip under the sleeve and by the outflow of aspirating solution through the needle. It is however the irrigation flow which does the main work. If the sleeve is too tight in the incision, it chokes off the irrigation flow allowing the temperature of the phaco tip to build up which is liable to produce corneal burns. The biggest disadvantage of corneal burns is that it makes the cornea at the burnt area shrink slightly, which retracts creating a bridge over the incision, no longer functioning as a self-sealing incision and even requiring sutures to close the incision adequately on completion of the surgery. The problem of a proper size incision can be solved by using the appropriate blade, calibrated precisely for that incision’s requirement. One of the advantages of a diamond blade is that a 2.8 mm blade will give you an exact 2.8 mm incision. Since no pressure needs to be applied on a diamond blade during entry, the width of the incision remains a constant. If on the other hand the incision is too wide, fluid tends to escape from the sides, disproportionately, with the result that the chamber depth tends to fluctuate and is even liable to collapse. If the IOP of the patient is high, more so if the vitreous pressure is also high as occurs in myopes, a fluctuant chamber is liable to lead to a break in the posterior capsule. In addition the outflow from the leakage sites coupled with the outflow from the bore of the needle would mean that during phaco one can be saddled with an unstable, ever changing anterior chamber depth with a bouncing (trampoline) posterior capsule. A single mistake will lead to a rupture of the posterior capsule with a vitreous break.

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Fig. 37.1: Small pupil being dilated with two ball-tipped IOL rotator

Fig. 37.2: The pupil is diltated vertically first

Fig. 37.3: It is then dilated obliquely

Fig. 37.4: Shows the dilated pupil with small sphincter tears

Fig. 37.5: Narrow pupil about to be dilated with Grieshaber hooks

Fig. 37.6: Preparing to dilate pupil with iris hooks. Note—hook being placed at 5 O’clock position

The Problem with Side Port Incision A side port incision is very important. It is the entry zone for the chopper to enter into the eye and the port utilized to refill the anterior chamber at the end of the surgery. An incision made too close to the limbus will tend to impinge on the iris.

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Fig. 37.7: Two hooks being placed

Fig. 37.8: Four hooks with pupil well squared

In addition BSS escaping, will tend to cause the conjunctiva adjacent to the site to balloon up, making phacoemulsification difficult. In case the tunnel is of inadequate length, it will tend to leak. An easy way to get a proper length side port incision is to use an MVR blade (Alcon, or any other manufacturer’s, 1.2 mm width blade) and insert it at a horizontal plane to the cornea. If the incision is made accidentally, too Fig. 37.9: Phacoemulsification proceeding under wide, there will be continuous leakage, hooked squared pupil which would lead to unstable anterior chamber. In case the incision leaks excessively, it would be safer to place a suture and then continue the surgery via a new side port, as it will prevent problems. Complications during Capsulorrhexis The capsulorrhexis is a basic requirement for good phacoemulsification as it allows the formation of a proper capsular bag, which permits phacoemulsification to be done within the confines of the bag. It also has the advantage that it permits a perfect placement of the IOL without any pressure on the sulcus. It is the bag, which permits intracameral gymnastics permitting the easy and safe removal of the nucleus. It is important that the capsulorrhexis have a perfect round circle, which is neither broken, nor has any nicks, which would permit the capsule to tear when stretched. To do a proper capsulorrhexis one needs to have perfect visibility, a good chamber filled with viscoelastic and either a sharp bent needle or fine pointed capsulorrhexis forceps. It is always important to keep chamber well inflated with viscoelastic. Healon is best but is costly. Iced methylcellulose seems to work extremely well and maintains a constant compression on the surface, and most important of all, being highly

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viscous (icing makes the methylcellulose increase by in viscosity by a factor of three), does not readily come out of the chamber, keeping it well inflated at all times. Problems with the capsulorrhexis Among the problems, which can occur during a capsulorrhexis, the most frequent is a rhexis, which escapes off into the periphery. The reason is not hard to see. The anterior zonular fibers fan inserts onto the anterior capsule usually at 8.5 to 9.00 mm from the lens center, however some aberrant fibrils will extend anteriorly up to the 7.0 mm from the lens center (Eisner, 1975). If a rhexis extends out to this level and reaches the zonular insertion on the anterior capsular membrane, rather than turning smoothly the rhexis will be deflected along the zonular path, literally, running off into the periphery. It is possible to shift it again, using a forceps, but be sure to use a repositor to sweep the anterior capsule free of zonular adhesions prior continuing the rhexis. With the rhexis forceps, grasp the edge of the capsule and swing it sharply inwards. Usually it is more than adequate to get the rhexis going again around. Another easy way to tame a rhexis, which has run away from you, is to redirect it using a fine scissors, (a long-bladed Vannas scissors is ideal). Make a small fresh cut in the direction you want the rhexis to go and, holding the edge of the freshly cut capsule, complete the rhexis. Be very certain not to exert stress at the place where you have reverted the flap, as the initial extension is likely to go to the periphery with problematical consequences. Another method is to place a repositor under the edge of the rhexis where you wish it to go, use a sharp pointed needle and nick the capsule, Holding the inner nicked part of the capsule, complete the rhexis, bringing the advancing flap over the initial cut edge from the out, in. This will once again restore the capsular bag integrity. Prevention of Complications with Hydrodissection To prevent complications occurring it is important to use a proper technique. The technique involves injecting a small amount of fluid (Ringer lactate or BSS) under the anterior capsule with a fine blunt cannula connected to a 3.00 ml syringe. Because of the fluid pressure and the dissecting ability of the fluid to take the path of least resistance, the fluid separates the cortex and the epinucleus and partly separates the capsule and the cortex. The ideal technique of cannula placement for effective hydrodissection is to place the cannula just within the capsulorrhexis edge, slightly tenting it or lifting it upwards. This technique termed as “cortical cleaning hydrodissection” was originally conceived by Dr Howard Fine. Injecting the fluid along the rhexis edge permits the fluid wave, literally to shear close to the capsule, thus significantly diminishing the quantum of cortical remnants which will need to be aspirated after the primary nucleus is removed by phacoemulsification.During the hydrodissection, unless it is a very hard cataract or an opaque one, the fluid wave can be seen clearly to separate the cortex from the nucleus, and is indicative of a successful hydrodissection. Hydrodissection

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is usually carried out in three sites commencing with the 4.00 O’clock position followed by the 2.00 O’clock position and finally followed by hydrodissection at 8.00 O’clock position. It is important that small aliquots of fluid be utilized, as excess fluid especially in a hard brown cataract is liable to balloon the capsule posteriorly, rather than spreading as a wave, and may, if more fluidic pressure is applied, rupture the capsule. It is important to visualize while injecting the fluid diffusion wave. The ideal syringe is a Luer-Lock, plastic, disposable, Teflon-coated or siliconized, of 3.00 ml capacity. This type of a syringe permits a better control, prevents application of too much pressure. Being Teflon coated, or siliconised, the piston moves very smoothly, and does not stick. Too thin a cannula, (ideal is 24-26G, flat cannula), even if blunt is liable to puncture the capsule if accidentally inserted too far into the periphery. In addition, a thin cannula permits the fluid to emerge in a sharp jet, at high velocity, which is not required. The one way to be sure the hydrodissection is complete is to check whether the nucleus rotates freely in the bag. In all cases, hydrodissection should be followed by mechanical rotation of the nucleus to be sure the nucleus rotates freely and that all adhesions have broken down. It is important to appreciate that the lens does not rotate freely one must do hydrodissection again, and again, and again, until smooth rotation is achieved. It is important that after every injection of fluid the lens should be gently pressed backwards. This technique is termed as “compression hydrodissection” and works by causing the fluid to disperse and spread out as a flat lamellar zone at the back of the nucleus and thereby enhance the hydrodissection. This technique should compress gently following each injection of fluid under the capsular flap. Compression hydrodissection thus decompresses a filled capsular bag, and at the same time shears off any adhesions. Managing complications in hydrodissection It is imperative that the quantity of BSS injected under the capsule should never exceed 0.5 ml at a time. In addition, to prevent the risk of inadvertent perforation of the anterior capsule, always use a 24 to 26 G blunt cannula. Always lift up the edge of the capsule. Besides doing a good fluid wave, this technique also prevents accidental puncture of the capsule, which will nick and weaken the rhexis. It is important to always press on the nucleus after every injection to be sure that the fluid is dispersing well and not accumulating below the nucleus, which may lead to a rupture of the distended posterior capsule. Impending Rupture of the Posterior Capsule Every surgeon, at some time or the other is liable to break the posterior capsule during hydrodissection. If one learns to identify the signs of an impending rupture, it can be handled safely. In case rupture does occur, it is important to identify it early, as soon as it occurs, so that the problem can be managed smoothly with minimal complications. The earliest signs of an impending rupture is to have the iris/lens diaphragm move forwards reducing the anterior chamber to a thin chink. At this stage, if the

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Fig. 37.10: Implantation of Allergan SI 40 lens

Fig. 37.11: Rupture of capsule during phaco

Fig. 37.12: Insertion of IOL following removal of cortical debris

Fig. 37.13: Showing subconjunctival swelling due to poor position sclerocorneal incision

surgeon panics and tries to force the reformation of the anterior chamber by injecting viscoelastic under pressure or, worse still, tries to push on the nucleus, in a backward direction, it will immediately lead to a rupture of the posterior capsule. The method of handling it at this stage is simple. All one needs to do is to take a thin blade iris repositor and introduce Fig. 37.14: Excess subconjunctival edema due to it under the capsule in the 5.00 O’clock retrograde flow from a poorly designed incision position and then sweep in, under the capsule to 3.00 O’clock position and then to the 7.00 O’clock position. Almost immediately, the surgeon will be rewarded with a gush of fluid indicating that the block has broken Managing the ruptured capsule after hydrodissection Rupture is detected by the tight eye suddenly going soft, and the iris and the nucleus moving backwards with the chamber deepening. At this stage though the posterior capsule has ruptured,

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the nucleus and the cortical material stay in the same place in the posterior chamber. Inadvertent and inopportune surgical movements will now precipitate a problem with the nucleus luxating into the vitreous. If the nucleus is likely to drop into the vitreous or has luxated into the vitreous, its technique of management has been discussed later in this chapter. Problems and their Management during Phacoemulsification of the Nucleus Essentially phacoemulsification can be divided roughly into two eras: The Pre-Chop and the Post-Chop era. The Pre-Chop era was dominated by the methods of grooving and splitting and then finally flipping. It is still a common technique in use today in India and thus is being evaluated in detail. Problems with Nucleofractis and in situ (Four quadrant) Phaco Fracture Technique Nucleofractis or divide and conquer was first commenced by Gimbel 1986 subsequently modified as a 4 quadrant or in-situ method are perhaps some of the most common techniques being used in India. They were the precursor to the Nagahara chop technique, which has literally revolutionized the Phaco surgical scene. Hydrodelineation in this procedure is very useful as it tells the surgeon how far he or she can go into the periphery without any risk. The phaco settings should be set at 75 percent power but with minimal aspiration and a low flow rate. Be always sure to have a perfect hydrodissection. The nucleus should spin like a top in the bag. In both the nucleofractis as well as the 4-quadrant technique, the problem always has been, the depth of the grooving should be adequately deep to get to the thickness level for a proper split to develop. For a proper groove, one needs to shave off the nucleus, layer by layer, taking care not to bury the tip, making sure only the lower third of the tip is occluded. The bottom of the groove is typically at the level of the posterior Y-suture. The red reflex can also be used to gauge the depth of the groove. It gets progressively brighter as the midline is passed. Care should as always be exercised that the grooving is done in a bowl fashion, deeper in the middle but shallower in the periphery. As a routine, make all the four grooves meet in the middle and communicate with each other prior splitting. This will make sure that the crack or split goes all the way to the bottom. It is important if one is to achieve a good split that the surgeon places the tips of both his or her cracking instruments at the base of the groove. The cracking or splitting can be done effectively in two ways. • A direct split, i.e. the instruments are placed at the base of the groove (a blunt dissector or chopper in the left hand, the phaco tip in the right hand) and the groove walls are separated. • In a contralateral split, the two instruments at the base of the groove cross over themselves, i.e. the phaco tip, though held in the right hand, presses the left sides of the groove and vice versa.

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In a soft cataract, a direct split is easier. In a hard cataract, better leverage is obtained with the contralateral split. Cracking the lens through both the grooves fully, convert the round grooved nucleus into a four-piece pie. Now, rather than trying to pull out the piece with the phaco, (a dangerous and often futile maneuver), lever out the tip of one piece using the left hand held, blunt probe. Let the tip impinge onto the phaco tip; turn on U/S and phaco it out. The phaco settings at this time should be changed, high aspiration rate, a high flow rate and moderate phaco power. Most surgeons nowadays, who are still utilizing this technique, make only a single groove, split the nucleus apart and then at this stage turn the nucleus high around, using the phaco chopper in the left hand impale the nucleus, and then chop it into two or more parts. Its saves a great deal of time and works equally well. For harder cataracts Gimbel had in 1992, devised the Down-slope technique. The technique involved pushing the nucleus downwards towards 6.00 O’clock with the spatula while the grooving is done. It had many advantages. It was a safer, better-controlled maneuver and could get the groove done longer, and deeper and thus making splitting hard cataracts easier. A further modification of the above technique was the Crack and Flip technique (Fine, Maloney and Dillman, 1992). Once again a variation of an established technique done to compensate for the problems in the previous methods. The grooving and cracking as per the previous techniques, the residual epinucleus is flipped out by gently holding it using low aspiration with the phaco and with the other hand rolling it or flipping it out. This solves the often-problematic epinucleus removal. The Flip method enhancing safety for epinucleus removal, is a useful technique, and should be in every surgeon’s armamentarium. Complications with the Phaco-Chop Techniques The Post-Chop era of phacoemulsification commenced with Nagahara describing it at the ASCRS meeting at Seattle in 1993. A novel, new approach by chopping a nucleus into its component parts directly. The entire concept was that the nucleus is held firm by the phaco tip while a sharp tipped chopper is used to score the surface of the nucleus and then split it down. It made a world of difference as grooving was unnecessary and there was no need to go into the depths of the groove for the cracking. The risk to the capsule dropped drastically. In addition, the surgery became, more predictable and faster. Even the hardest lens could now be chopped (at least partially). Managing problems with the phaco chop technique Fixation of the nucleus Unless it is properly fixated, the nucleus would slide off the phaco tip. It makes it easier to use the tip with the bevel forwards rather than down. Place the tip on the surface of the nucleus just within the rhexis at the 12.00 O’clock position, turn the phaco power on so that the tip sinks into the nucleus and wait till the suction builds up to its maximum preset limit. Keep the tip pressed down gently and only then position your chopper for the next step.

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Selection of the chopper The chopper has to be sharp to score the nucleus. The tip has to be at least 1.5 mm long. It is preferable if the tip is slightly flattened so that resistance will be encountered with side movement, which will make the chopping easier. The novice often errs on the side of using a short, blunt chopper, a guaranteed recipe for failure. If possible, the chopper should have its flat side slightly skewed by 20 degrees. Since the chopper and the phaco tip will be separated by an angle of usually 30 degrees, skewing the angle of the flat sharp side of the chopper makes for easier chops especially in hard cataracts. A single point of caution: to keep the tip of the chopper sharp, always leave it covered by a silicone tip when not in use. There are places where a blunt chopper proves useful • Tangential chop technique. The chop goes tangentially against the substance of the lens • When the fragment are small, but the cataract is hard, a sharp sided, blunt tip chopper is preferable as it can repeatedly make into thin slivers the hard cataract and allow easy aspiration with the phaco tip. • In soft cataract where there is a risk of the chopper sinking through the substance of the lens. Here if the chopper tip is sharp, the capsule is at risk. • In anterior chamber phaco, when the lens is rotated into the anterior chamber, one goes from the side and does a peripheral chop to prevent accidental corneal touch. The lens is spilt from the sides; the blunt tip prevents entanglement and injury to the iris. Placement of the chopper tip The chopper is inserted flat through the side port incision, taking care that the iris does not entangle in the sharp chopper tip during insertion. Once the nucleus is fixated, go back from the tip by 3.00 mm and impact your chopper in the nucleus. This distance of 3.00 mm from the phaco tip is usually enough. It is unnecessary to go under the capsule to the equator of the nucleus, Now place the sharp edge of the chopper against the nucleus, press gently downwards and pull towards the phaco tip, While the Phaco tip holds the nucleus steady, the chopper first scores the nucleus, and then buries itself deeper, in the manner of a plough. When close to the phaco tip, the chopper is moved to the left, while the phaco tip moves to the right, splitting the nucleus into two. The action is almost like splitting a log of wood after embedding an axe into it. The important step is to keep the downward pressure on the chopper as it moves towards the phaco tip. That particular movement buries the chopper deep in the nucleus. Also remember to allow both the instruments to separate so that the cleft deepens. Proper holding of the nucleus for a chop One of the common complaints is that the nucleus shifts off the phaco tip preventing the execution or completion of a proper chop. This is because of an inadequate impalement of the phaco tip. To get a proper impalement the phaco tip must be buried in the depths of the nucleus. To get a proper depth, two steps are important: first as one enters the eye, on the surface of the nucleus, swirl the tip around without ultrasound—this will remove the superficial epinucleus exposing the harder nucleus below; and now,

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the second step, with a little ultrasound power make a shallow saucerized space in the middle. With your phaco tip bevel, facing forwards apply the phaco tip just ahead of the upper (12 O’clock) edge of the rhexis and with a single burst of ultrasound bury it in the nucleus. Wait until the suction rises to its preset limit and then proceed with the chopping. It is also possible to bury the phaco tip in the nucleus, bevel down. Many surgeons advise it as it prevents too deep a placement of the tip with relation to he nucleus. The only disadvantage is that with the bevel-down technique, the suction needs to be kept much higher or as one tries to chop, the nucleus simply drops off the tip. Rather than making a direct impalement (bevel down or up, at the surgeons discretion) many authorities (Koch et al) Stop and chop) recommend that a shallow groove be first prepared, turn the lens at 90 degrees to the groove and then impale in the substance. In this way, the nucleus is held firmly and with hard lenses, the chop can be done with adequate force. Rotation following the phaco chop Rotation of the nuclear fragments in the bag can be a problem sometimes as after dismantling the pieces the place in the capsular bag becomes very, limited. A simple technique is to lever out one tip of the chopped piece with the tip of the chopper, and to phaco it off. Automatically space is increased, and it makes more room for better rotation and more place for the segment to move when they are being chopped which leads to better and deeper chops. Chopping very hard nuclei (6 +) is very difficult. This is because of the harder central nuclear zone, which has a different density and therefore does not chop through. To remove it, many new techniques have been developed. The “shelling” technique (Mehta, 1997) is perhaps the easiest. Make a central chop, and then extend it to the side. This will expose the central nucleus. Phaco this central nuclear zone separately with simple aspiration and ultrasound. This part of the nucleus is a homogenous material and does not need to be chopped. This now leaves an empty bag of nucleus, which is flipped over, and phacoed. Another, more innovative method is the “saddle hump” technique. It is based on the concept, that if one breaks the binding of a book, the pieces come apart and then can be easily tackled. In the saddle hump technique, (Mehta, 1999) the edges of the nucleus are clipped or lifted off with a special chopper, and gradually the lens is unraveled. The surface is phacoed separately as is the central area. The deeper posterior nuclear material is flipped over and then phacoed. Both techniques have been described in Chapter 28 on Suprahard Cataracts: Their Evaluation and Management. To convert or not to convert. Aye that’s the question Whether it makes sense to continue a difficult case, or to call it a day and convert to a standard ECCE, is a decision every surgeon needs to make for himself. He or she has to consider the patient, the density of the cataract, the state of the corneal endothelium, (consideration is even more critical if this is the only eye of the patient). Against this has to be balanced the surgeon’s knowledge, his or her faith in his

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or her own skills, his confidence in himself and his ability to handle a complication if it precipitates. Another important point to consider is the machine, which is being used by the surgeon. Some machines have very good fluidic control and exceptionally fine ultrasound and aspiration ability, and automated anti-surge controls. (The Alcon Legacy, the Allergan Sovereign and Diplomax and the Storz Millennium). Tackling a difficult case with these units will naturally be far easier than doing it with a small economical machine, which does not have the appropriate capabilities. That is not to decry some of the smaller machines, which work perfectly well, but in a difficult situation the better the machine the more superior are your chances of staying on the top of a difficult phaco situation. In a hard cataract, an intact, well-designed, capsulorrhexis is mandatory. No rhexis: abort and convert, for inevitably, in a majority of cases you will land up in trouble. The moment for conversion is when the surgeon starts feeling unhappy with the situation—too hard a lens, a nucleus refusing to chop and fragment, a rhexis which is inadequate, an eye not responding as it should, a patient who is becoming difficult, all tell the surgeon that it is the time he or she reconsidered his or her options. It makes more sense to convert. If any doubt exists regarding the integrity of the zonular or even, the bag, in a very hard cataract it is grounds for immediate conversion. Problems in Conversion to ECCE A hard nucleus is also unfortunately a large nucleus, with negligible buffering epicortical material. Hence, if it is to be extruded from the bag, you will need to cut the edge of the rhexis in at least three locations, two clock hours apart. Failure to do so will lead to an inadvertent intracapsular extraction and/or a vitreous break. Do also remember that with an intact capsule, the hydrodynamics of nuclear expression are quite different and simple pressure or counterpressure will not work. You will need to manually shift the lens into the anterior chamber by rotating it out and only then expressing it out or hydroexpressing by a side port retainer (Blumenthal). At this stage, the use of viscoelevation is very useful. Inject viscoelastic at the edge of the nucleus. If the bag is intact, the nucleus will float (Visco-levitate; Kelman: Mehta) into the anterior chamber. Another simple way is to do a supracapsular tumble (Maloney, 1998) , following a rhexis multiple cuts, and shift the lens in front of the anterior capsule. At this point, one can phaco it or extrude it out of the anterior chamber in a sliding ECCE technique. Managing the intact posterior capsule It is important than that the posterior capsule remains clear so that the visual axis is not impaired by any opacity. A certain percentage of capsules will always opacify. The younger the patient the quicker the capsule opacifies. In a young child of 2 to 4 years, the capsules will opacity in just a few months. Between the ages of 5 and 15, the average opacification time is about 10 to 15 months. A young adult between the ages of 20 to 40 years

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will opacity in about 2 to 3 years. Those between the ages of 40 and 60 are likely to opacify in about 4 to 6 years while those over the age of 60, many last for many years before the need arises for the capsule is to be managed. Lest it be misinterpreted that all capsules opacify, the average percentage runs between 30 and 50 percent depending on age. The younger patient’s capsules all opacify, while in the older + 60 age group hardly 8 to 10 percent opacify. It would therefore make sense that the capsule is managed to as soon as it tends to start becoming opaque. Treatment of this opacity can be done during surgery (intraoperative capsulotomy) or as a secondary procedure, done at a later date (postoperative capsulotomy). There are some patients in whom the capsule should always be left intact even subsequently. Those with high myopia especially with retinal changes or who have had a past history of retinal detachment, either in that eye or even the other eye, those who have had cystoid macular edema (CME) in the other eye and those in whom there is a possibility of a future fistulizing operation. Though for practical purposes a capsulotomy may be needed in future, the surgeon must try minimizing the possibility of capsular thickening by leaving the capsule as clear as possible. Among the methods, which can be utilized, are to do an excellent irrigation/aspiration to remove all cortical material, which may reduce the spontaneous reabsorbance. Polish the capsule to eliminate as many proliferative cells as possible to avoid the secondary opacification of the posterior capsule. It is also imperative that all viscoelastic substances, which had been utilized during surgery especially at the time of implantation, be meticulously removed as this leads to opacification. Cleaning the capsule can be done in following ways. • With a hand-blasted or a diamond tipped irrigating cannula • With a ring polisher, which will permit, polish of the posterior as well as the anterior capsule • With the automated capsule polisher and in which the vacuum is kept at 5 mm Hg. • With an ultrasound polisher, which has rounded, tip and which can be moved over the capsule, which shakes the cells loose. Intraoperative Primary Posterior Capsulotomy It can be done in a variety of instruments however the most frequently used instrument is a fine needle (26 G), which can be attached on a syringe filled with viscoelastic. Method of Polishing the Capsule • The Kratz cannula is a simple irrigation cannula that is blunt at the tip. The roughening has been generated by sandblasting the tipped end. It is important that in using this cannula, the flat surface be kept parallel to the capsule, and it should be moved gently so that it does not fold or ruck the capsule and tear it. (The term “rucking” needs some explanation. Rucking is the term which is

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applied to forward bunching of the tissues. If one runs a finger over a loose sheet of cloth, in advance of the finger the cloth bunches and forms ripples. This is termed as rucking) • Diamond impregnated polishers should be used with great caution as they go through the capsule very easily. They are to be used only when the encrustation on the capsule is very thick and one needs to lift off the encrustation. With a diamondimpregnated polisher you do not scrape the polisher over the capsule as you will immediately tear the capsule. You only gently get to the edge of the encrustation and try to lift it off. • Vacuum capsule polishers are essentially the standard Irrigation/aspiration handpieces, with a 0.3 mm port. The irrigation is diminished to 30 cm and the vacuum is kept very low at 5 to 10 mm Hg with a very low flow rate of 5 to 8 ml/min. The orifice is oriented onto the capsule and while aspirating, it is gently moved over the surface of the capsule. It is important not to ruck the capsule. The secret of using this technique is to take your time. It works well and all the fragments from the anterior capsule as well the posterior capsule can be gently removed. It is important that the tip be kept moving when the suction is on. If it is left stationary for any length of time, the capsule is liable to be trapped in the orifice and may be torn if suddenly pulled. In addition the irrigating bottle are kept low at the level where the capsule becomes flat, and does not bulge backwards. • The ultrasound polisher is essentially a blunt needle with rounded tip and roughened, connected to the ultrasound handpiece. It must be used only after the manual vacuum polishing of the capsule is complete as by itself it is unable to complete the entire job. It shakes off the final loose cells and is like a mopping up type of operation. The U/S needs to be set to the minimum of 5 percent (depends from machine to machine). It is important that the maximum possible magnification be utilized with which the surgeon feel is comfortable so that the small deposits, and areas of opacified cortex can be identified and removed. If the cortex is very transparent, avoid trying to polish it as it only puts the integrity of the capsule to risk. The pressure exerted by the polishing/cleaning instrument should be such as to encourage only blunt dissection and should be able to abrade off the particles without damaging the capsule. The key to evaluate the quantum of pressure applied to the capsule during the polishing phase is by looking for the circular reflex on the capsule around the tip of the polishing instrument. Normally the circular halo should not exceed 3 to 4 mm. any more and you are applying too much pressure. Looking at the halo will also tell you how clean the capsule is and if there are any residual debris left, or if it is uniform and regular, and free of any deposits In case of any resistance encountered while polishing the capsule, immediately desist from polishing further because the polisher may have insinuated itself into the capsule. The watchword for capsule polishing is caution.

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The capsule is best kept under slight tension by raising the irrigation bottle until the capsule is perfectly flat. The risks of breaking of the capsule increase if the pressure of the irrigation fluid is kept too high, which will make the capsule deeply concave, or if the irrigation is too low, which will make the capsule convex. Causes for Rupture of the Posterior Capsule • Accidental momentary touch with the ultrasound phaco tip This should, in theory, have no effect as contact of the posterior capsule with a smooth rounded phaco tip, with the ultrasound on, provided it is not moved, should cause no damage. In practice however, no phaco tip is perfectly smooth. After some usage (in most countries, tips are used till they literally die out), the tip is scratched and has multiple sharp edges at the tip. If the suction is not too high one may still get away with a small round hole with an intact hyaloid membrane, but invariably, due to the high suction combined with the high volume of infusate, complicated with tip movement, the tear invariably is complicated by the presence of vitreous. • The laceration of the capsule during chopping It occurs when the chopper is taken too far into the periphery and the chop includes the edge of the rhexis. If the chopper is very sharp, only a capsular edge tear will occur, but if, as is frequent, it is slightly blunt it will avulse the capsule. It also occurs when splitting the pie sectors into smaller bits prior aspiration with minimal ultrasound. It can be prevented by more attention on the part of the surgeon with better light and sharper visibility with higher magnification. • Discontinuity of the anterior capsule with a tear that extends backwards involving the posterior capsule invariably occurs when the capsulorrhexis has been made improperly, or the edge of the rhexis has run off into the periphery. In these patients, any intracameral gymnastics leads to tear extension with a posterior capsular tear in consequence. • Zonular disinsertion especially when the zonules are weak as in cases of pseudoexfoliation or in cases of hypermature old neglected cataracts or following injury. However, not technically a posterior capsular rupture it behaves in an identical manner. Signs of a Posterior Capsular Rupture The most common sign is deepening of the anterior chamber and shift of the irislens diaphragm backwards. The chamber is likely to become deep irregularly. In addition, the nucleus and the cortical fragments seem to move slowly by themselves. Nuclear rotation if attempted will show restriction of movement. When left after rotation the fragments partially creep back to their initial places. These changes are because of the admixture of the vitreous in the anterior chamber. Another important sign is that the phaco will stop working because of vitreous in the phaco tip. If the capsule ruptures towards the end of the phaco procedure, this may even be the earliest sign. Occasionally a small piece or even, if the surgeon is unfortunate, a large piece of nucleus will luxate or drop into the vitreous cavity.

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The moment there is any doubt about a posterior capsule rupture, even if little, it is important to immediately stop the phaco, take the phaco tip out of the anterior chamber. Continuance of the phaco procedure will lead to extension of the tear with severe complications with a dropped nucleus and admixture of the cortical remnants in the vitreous with vitreous in the anterior chamber. Managing the Broken Posterior Capsule The rupture of the posterior capsule with its attending complications is one of the most feared complications of Phacoemulsification The management is dependent on whether the hyaloid face is intact, the size of the tear, the stage at which the phacoemulsification procedure has reached and the complications which have ensued prior the surgeons recognition of the posterior capsular rupture Rupture of the Posterior Capsule without Hyaloid Face Rupture If the capsule gives way at an early stage of the nuclear phacoemulsification, it is important to inject viscoelastic below the nuclear fragment and gently try to maneuver the fragments in to the anterior chamber. If Viscoat is available, it is an ideal material, but in its absence frozen (iced) methylcellulose will work. If the nucleus is hard and the size is big or the rhexis size is small, you may need to give two relaxing cuts at the edge of the rhexis to permit the nucleus to float out with a little help from a spatula. Never inject viscoelastic under the lens as the pressure of the viscoelastic will rupture the hyaloid face and complicate matters. It is best not to exert any pressure on the hyaloid face, nor on the posterior capsule, as it will cause the tear to enlarge in size. A spatula in one hand and a sharp chopper in the other will coax the nucleus in the chamber. Once the nucleus is brought in the anterior chamber, we have three alternatives. • The simplest is to remove the nucleus by extending the incision. Again, apply no counter pressure. Work the nucleus out, under the cover of a little viscoelastic, with the edge of the sharp chopper to maneuver it, and roll it out sideways. Following its removal do a gentle irrigation /aspiration to remove the cortical remnants. The IOL can be fitted in front of the anterior capsule as a sulcusfixated IOL. • In case the surgeon is confident of his or her own abilities and the nucleus is not too hard, he or she may continue phacoemulsification in the anterior chamber. The nucleus once again needs to be maneuvered into the anterior chamber and a lens glide needs to be slid between the nucleus and the posterior capsule. You may also utilize Miochol or injectable (unpreserved) Pilocarpine 0.5 percent. Lower the bottle, cut down the aspiration rate to 12 mm Hg, decrease the suction to 100 mm Hg (in the Alcon Legacy with the 0.9 mm tips), an ultrasound power to 40% and gently do a phacoemulsification. Chop the nuclear fragments into little bits and phaco them.

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• If most of the nuclear material had already been removed prior the break, continue with the phacoemulsification, after placing a bolus of iced methylcellulose or Viscoat at the broken site and after lowering the bottles ( I/2 meter above the patients eye), gently proceed with the cortical remnants removal and implant the IOL in the sulcus. If one is confident of one’s abilities to do the I/A in these circumstances, dry (under viscoelastic) cortical aspiration can be carried out. Inject viscoelastic from the side port and at the same time continue to gently aspirate out all the cortical remnants. Be extremely careful. No sudden surge in pressure must occur, as the hyaloid is very fragile Rupture of the Posterior Capsule, with Hyaloid Face Rupture, but without Luxation of Nuclear Material into the Vitreous Immediately stop any irrigation in the eye. The entire secret of handling the situation is to use, as far as possible, zero fluid. We can consider three situations, • If the opening is small and the lens fragments are not too big (i.e. we had almost reached the end of phacoemulsification when the tear occurred As a first step , inject viscoelastic under the fragments to support them. Next, try to work the fragments one by one into the anterior chamber. If the fragments are not coated with vitreous and the surgeon was alert and responded immediately to the capsular break, the Viscoat or methylcellulose will force the fragments gradually up in the anterior chamber. Try to work as many of the nuclear fragments as possible up into the anterior chamber. Next, place more viscoelastic and then insert your phaco tip, with only aspiration, irrigation should be very minimal and via the side port and only allowed in when the phaco tip U/S functions and when the suction is gently on, suck. Use gentle suction with only an occasional burst of low-intensity ultrasound. There is always the question of a corneal burn occurring with little or no irrigation, but remember a burn only occurs if the intensity of ultrasound is over 30 percent and is a continuous burst. Alternatively, you may open the incision to 6 mm and gradually with a thin blade wire vectis and spatula remove the fragments. Subsequently inject viscoelastic and do a “dry” vitrectomy, remove all the fragments. Let your vitrectomy go 5 mm deep into the vitreous, under the capsular tear, again do a little dry vitrectomy. Keep a BSS-filled syringe in your hand and only replenish the chamber if the chamber starts to collapse and fill in just enough so that the chamber fluctuation is minimized and the chamber is well maintained. This semi-dry vitrectomy technique works great and you will be able to remove virtually all the remnants and the cortical material with no problems. • If the nuclear fragments are very large, i.e. the break occurred, but the fragments do not show signs of an incipient luxation Here it is important to first inject viscoelastic under the fragments and support them with a thin blade spatula and gradually maneuver them into the anterior chamber. The Incision is now widened to accommodate the lens nucleus for its

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removal. Using the sandwich method (spatula or wire vectis below, a flat broad blade iris repositor in front, the entire lens or the largest fragment is supported and then slid out of the chamber. Again, viscoelastic is filled and dry aspiration of the residual cortical fragments can be carried out. It is important to do vitrectomy within minimal BSS irrigation but with more of viscoelastic. Subsequently the IOL is placed on the anterior capsule in the sulcus. • If the fragments are large, i.e. the break occurred, and the large fragments are showing signs of an eminent luxation The method of handling this problem is termed the cruciate technique. A slightly different technique, but essentially similar has also been described by Charles Kelman (1998). All one does is to take two MVR blades (Alcon) and insert them 5.00 mm from the limbus through the conjunctiva and the sclera via the pars plana into the vitreous and out the same way from the opposite side. Place the first one at 7 O’clock position; emerging again at 2 O’clock. The second one is placed at 4 O’clock and emerging at 10 O’clock position. The assumptions being that you are operating at the 12 O’clock position. In case you are operating temporally, change the position of the MVR blades so that they do not interfere with your routine surgery. Now introduce viscoelastic and then, using dry dissection, first aspirate out all the cortical material, leaving behind only the hard nucleus.Narrow the pupil with Miochol or with pilocarpine 1 percent eyedrops. The next step is to insert a plastic 3.00 mm wide plastic slide. This slide can be made from the sterile plastic over wrap, which comes with the intraocular implants. Slide it below the nucleus so that it occludes the narrowed pupillary area. Now that the nucleus has been stabilized one can open the chamber and using the sandwich technique remove the fragment, or if the nucleus fragment seems soft and the surgeons very sure of his or her rability, he or she may try to gently phaco the fragment out. Lower the bottle height to 1/2 meters above the patient’s eye. Reduce flow rate to 12 mm Hg. Minimize the quantity of fluid entering the eye and do a dry phaco using viscoelastic, the BSS being only used to replenish the chamber in case it looks as if it is liable to collapse. This will slow down the pace in the chamber. Reduce your ultrasound energy to pulse phaco with a maximum setting of 40% power. Reduce aspiration rate. Maneuver the nucleus into the anterior chamber ahead of the iris. Now proceed with a slow phaco using a phaco chop technique. Use minimum ultrasound power. Move slowly. There is no hurry. You should manage to complete the phaco with no difficulty. Now insert your IOL, preferably foldable. Place it in the anterior chamber. Do not remove the slide yet. Maneuver each of the loops into the sulcus, in front of the anterior capsule. Only then, remove the slide. Gently rinse out the chamber. Inject BSS via the side port and let the viscoelastic gently wash out of the main phaco entry port.

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Remove the MVR blades only as a final step. Done carefully the results are exceptional the next day. The eye is very quiet. Rupture of the Posterior Capsule, with Hyaloid Face Rupture, with Luxation of Nuclear Material into the Vitreous Unless the surgeon is very confident of his or her ability to do a good 3 port posterior vitrectomy and to handle a contact lens on the cornea, common sense would dictate that he does a little anterior vitrectomy, removes, using dry aspiration, as much of the cortical remnants and closes up. It does not make sense to place an IOL, as it would need to be removed by the retina surgeon when he or she gets the fragment out. The only time it is considered permissible to place the IOL in is when the material that has luxated is soft and the surgeon feels that with a phaco-fragmentor the retina surgeon will get the pieces out. Never try and sweep the vitreous with a vectis as this is almost a guarantee of either a massive retinal detachment with the eye immediately filling up with blood, if accidental retinal touch occurs, or a late detachment due to the gross disturbance of the vitreous at a later date. There are three ways the retina specialist may choose to remove the lens. • Using PFC (perfluorocarbon), after doing a full-fledged core vitrectomy, the nucleus can be floated up. Though it looks like a very simple technique, the PFC needs to be completely removed or else a severe reaction ensues and total removal is not within the province of the anterior segment surgeon. • Following a good three-port vitrectomy, the nucleus is speared and then gradually using a bimanual technique with the light pipe in one hand and a diamondcoated forceps or a spear in the other. The nucleus is gradually lifted to the anterior chamber where it is then removed after opening the chamber. • In an identical manner, following a vitrectomy, a phacofragmentor is introduced through one port and the lens fragmented in the vitreous itself. FURTHER READING 1. Mehta KR: When not to do an anterior chamber implant. All India Ophthl Soc Proc 164-65,1986. 2. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-66,1986. 3. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989. 4. Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in paediatric cataracts. All India Ophthl Soc Proc 207-10,1995. 5. Mehta KR: An advanced but simple keratometer for control of postoperative astigmatism. All India Ophthl Soc Proc 122-23,1990. 6. Mehta KR: An analysis of causative factor leading to eye strain caused by computer monitor screens. All India Ophthl Soc Proc 334-36,1990. 7. Mehta KR: Shelve and shear phacoemulsification. All India Ophthl Soc Proc (Mumbai) 1995. 8. Mehta KR: The prephaco split technique using the contrasplit forceps—a new technique. All India Ophthl Soc Proc, 1998.

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9. Mehta KR: Pupillary dilatation for recalcitrant pupils prior phaco with the new multipoint bicuspid pupil dilatation forceps. All India Ophthl Soc Proc, 1998. 10. Mehta KR: Use of intracameral yellow (Kodak Wratten 59 Filter) Fibreoptic light source for phacoemulsification in dense corneal opacities prior corneal transplantation. All India Ophthl Soc Proc, 1998. 11. Mehta KR: The tripod posterior chamber flexible acrylic implant—the answer to better stability. APIIA Conference, 1997. 12. Mehta KR: Astigmatic control using the new curved laminating keratotomy technique. APIIA Conference, 1997. 13. Mehta KR: The tripod posterior chamber foldable acrylic lens. Proc of SAARC Conference, Nepal, 1994. 14. Mehta KR: Phacoemulsification, the “roller-flip” way for suprahard cataracts—it works great. Proc of SAARC Conference, Nepal, 1994. 15. Mehta KR: Intralenticular phacoemulsification—a new technique. Proc of SAARC Conference, Nepal, 1994. 16. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 17. Mehta KR: Methylcellulose induced sterile endophthalmitis following phacoemulsification. Proc of SAARC Conference, Nepal, 1994. 18. Mehta KR: Double intraocular lens implantation for high ametropia and for correction of inadvertant remnant ametropia. Proc of SAARC Conference, Nepal, 1994. 19. Mehta KR: Comparison of scleral vs transiridial corneal suspended vs iridial suturing of PC IOL implants with inadequate capsular support. Proc of SAARC Conference, Nepal, 1994. 20. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

Durval M Carvalho Durval M Carvalho Jr

Management of Posterior Chamber IOL Capture

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INTRODUCTION When a posterior chamber IOL has part of its optical zone moved anteriorly to the iris, a pupillary capture1 is characterized. That is a complication inherent to the cataract surgery with IOL implantation. The frequency of such occurrence has been decreasing greatly due to the improvement of the surgeries, both for the improvement of the techniques and for the surgeon’s experience, mainly because in most of the surgeries the lens is placed “in the bag”2 they are smaller lenses, with smaller optical zone and with an adequate angulation.

Fig. 38.1: Pupillary capture

Fig. 38.2: Capture without synechiae

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We can have two types of pupillary capture: • Without posterior synechiae. • With posterior synechiae. PUPILLARY CAPTURE WITHOUT POSTERIOR SYNECHIAE This type of capture generally appears early after a cataract surgery, when the IOL is not placed in the bag3 and when, due to a trauma, the lens is moved anteriorily to the front of the iris; mainly if the pupil is still dilated. It can occur in cases of IOL scleral fixation, in which the IOL was tilted and part of it can easily move to the front of the iris. In cases of old surgeries this type of capture rarely occurs, because the IOL is, somehow, already secured to a structure, be it the posterior or anterior capsule, or to the iris itself; only a special trauma would dislodge the lens from its position. Patients with shallow anterior chambers, or lens with inadequate angulation of the haptics, damaged lenses, lenses not well centered, or placed in an inverted way would be more likely to this occurrence. These patients rarely notice the problem. The physician makes the diagnosis and depending on the cause, the correct treatment is indicated. In some cases, through light compression maneuvers on the ocular globe guided by the slit lamp images with a half-dilated pupil, one manages to reposition it.1,4,6 If this were not possible, one would have to return it to place by using the technique that will be described later on in this chapter. PUPILLARY CAPTURE WITH POSTERIOR SYNECHIAE In the medium or late postoperative period3 of the cataract surgery with IOL implantation, posterior synechiae conducive to pupillary capture may occur.3,5 Such occurrence is becoming rare, but when it happens it deserves a special attention. The predisposing factors favoring the lens capture are: IOL implantation in children or in the recently operated cases of retina or vitreous, in cases of combined glaucoma and cataract surgery, in cases of uveitis7, in traumas in general, in diabetic patients; in long-lasting surgeries with a lot of wash of the anterior chamber, in the inadvertent use of toxic substances in the anterior camera, in the not well-positioned lenses, etc. The signs and symptoms of the IOL capture will depend on the amount of the optical zone that is on the iris, on the time that it has been there, on the IOL attrition on the iris or if it is touching the cornea, and also on the patient’s own inflammatory factors as in the case of decompensated diabetic patients, or in chronic uveitis. By using the slit lamp one can see the lens in Fig. 38.3: Erosion of iris tissue

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front of the iris. Generally, pigments are found on the lens. And the posterior capsule presents with a certain degree of opacification caused by fibrosis and leading to a decrease in vision. One notices that in the area of the capture the iris is trapped in the posterior capsule. In the recent cases, the iris under the lens is just compressed by it. Over time, the lens chafing on the iris causes the iris tissue to become atrophic, making it more clear and allowing for a sharper visualization of the iris vases. Over time, hemorrhages in the anterior chamber may occur, leading to a chafing syndrome and ending up in glaucoma later. In some cases, a certain chronic perikerato hyperemia can occur, with a discreet tyndal. Another problem that can come up, due to the inflammatory reaction in the iris, is the CME, which causes loss of visual acuity. When a large area of the lens comes forward to the anterior chamber and moves to the periphery, there can be lens chafing on the corneal endothelium due to the normal movement of the eye. Sometimes this chafing is not noticed through the slit lamp and, however, a corneal decompensation starts appearing in that area. If this decompensation is not treated, it can develop into a bullous keratopathy, which will require a corneal transplantation later on. Small asymptomatic captures without any clinical evolution, as well as serious cases with low vision5, even with UGH syndrome, can occur naturally with all the intermediary possibilities. It is very frequent for the patient to have normal vision and yet to complain of some photophobia and an uncomfortable sensation of scratching in the eye at times. Treatment of the IOLs Captures with Posterior Synechiae In general, the treatment is conservative because the symptoms, in spite of being uncomfortable, are tolerable and the solution was not very exciting. To avoid using corticoids constantly and increasing the intraocular pressure, nonhormonal antiinflammatory, and sometimes some mild midriatics, is used at night. When there is CME it is naturally treated accordingly. In the most serious cases, demanding an intervention, the solution is to take the patient to the surgery room, to remove the synechiae as much as possible, and to place the lens again in its position. In these eyes, the iris is already atrophied and, when the synechiae are removed, it does not regain movement, ending up with a new synechia over time. In 1998, we presented in a film in San Diego, a technique that has been giving great results. It is a simple technique that can be used in the consulting room. And for this reason, even in the simplest cases which did not require any intervention some time ago, today when we do it the patient reports an improvement in his ocular comfort. Amazing results have been achieved in more serious cases in which the vision is quite impaired both due to the cystoid macular edema and due to the optic obstruction of the pupil, or due to the inflammatory syndromes. Surgical Technique for Correction of the IOLs Captures As these captures are caused by the posterior synechiae, the lens haptics will obviously be strongly stuck under the iris. The destruction of the posterior capsule will not,

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Fig. 38.4: YAG laser lens

Fig. 38.5: Limbus anesthetic

Fig. 38.7: Preoperation

therefore, hinder the lens stability at all. For this reason, instead of removing the synechiae we would rather use the YAG laser and do a large posterior capsulotomy, very close of the pupillary border, also making an opening in the center because these capsules are already quite opaque due to the fibrosis caused by the inflammatory processes. As soon as a good capsulotomy is done, one enters in this eye with a very delicate 30 G 1/2“ needle and this lens is pushed back. The optic portion of the lens will position behind the posterior capsule, while the haptics

Fig. 38.6 Needle position

Fig. 38.8: Postoperation

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Fig. 38.10: Hemorrhages due to YAG laser

Fig . 38.12: Postoperation

will remain in front of it. This way, the lens-iris chafing is stopped and the symptoms are improved. The way to accomplish this procedure will depend on the case. We used a lens devised specifically for iridectomy and manufactured by Meridian. It is a little different from the Abraham lens, because it magnifies the image on the whole surface of the lens, facilitating the use of the YAG laser without the need to rotate it and to find focus position. When it is a very simple capture, a YAG session is enough, using the necessary intensity according to the capsule thickness to create an opening large enough to push the optic part backwards. Then, in the consulting room, a drop of an antibiotic eyedrop and a drop of an anesthetic eyedrop are instilled, and a blepharostat, preferably with the base turned to the nose, is placed to leave the temporal limbus available. Next, a swab is wetted with anesthetic and kept against the temporal limbus for some seconds. After that, using a syringe with a 30 G 1/2“ needle the limbus is punctured. By placing the needle against the body of the IOL it is pushed back; first a half of the optic zone, and then the other half, if needed. Soon the whole lens will fit behind the iris and the posterior capsule.

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There are cases in which the fibrosis of the posterior capsule is very thick, and destroying it with just a laser session is difficult. In some cases, when using the laser close to the pupillary border, there appear hemorrhages due to vassels not previously noticed in the fibrosis; this hinders visualization and decreases the laser action, forcing to postpone the session. Cases in which the whole optic zone of the lens is in front of the iris, and the fibrosis of the capsule is very thick, the pupil is usually very small and no matter how large the capsulotomy is, there would still be difficulty moving the lens back. There are cases in which the tensile pressures of the synechiae are so strong that the lens haptic cuts the iris and moves into the anterior chamber, as if fibrous reconstituted the iris; with two or three YAG sessions one can also do an iridotomy in the projection of the haptic, thus creating a space to move it back without the risk of destabilizing the lens.

Fig. 38.13: Preoperation

Fig. 38.14: Postoperation

In these cases, it would be better to use some Xylocaine 1 percent in the syringe without preservative, slowly mixing it with aqueous humor in order to create enough anesthetic effect to pass the lens through the iris without the patient’s complaint. When the patient does not feel pain, he or she will not even notice the surgical maneuver. As the maneuver is made with a very fine needle, making the paracentesis in bevel and without causing trauma in the incision, practically there is no loss of the aqueous when removing the needle. With this, the anterior chamber is not lost. In spite of being a simple procedure it can be done in the surgical center by using the surgical microscope. After this procedure we prescribe antibiotic eyedrop in association with more corticoid and a nonhormonal antiinflammatory eyedrop 4 times daily for 20 days, controlling the ocular pressure accordingly. Complications in the Surgery of the Captures The complications are rare, what happens with certain frequency are the difficulties. The most common is hemorrhage during the YAG laser. Sometimes we examine a

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fibrosis that seems not to have blood vessels, but when we approach the iris bleeding starts. By using the lens we make a pressure on the eye and that usually causes bleeding to stop. However, it hinders the laser treatment, and we have to wait 2 to 3 days for continuation of the treatment. In some cases the fibrosis is so marked that even using high laser intensity it is not possible to cut it. In these cases if it is possible to use another area that can be used to solve the problem we will use it. On the contrary, we would have to insist on opening enough with the YAG to fit the optic part of the lens. Another problem is when the capsulotomy is insufficient and when, close to the inserts of the haptics, there is enough amount of posterior capsule to cause the lens to be impelled forward. At that moment the lens moves back under pressure, but soon it goes back to the anterior chamber. The capsulotomy would have to be enlarged and the maneuver would have to be repeated. The other complication possibilities are inherent to the application of the YAG laser, like the ocular hypertension that is usually transient. Retinal detachment, which also has its controversies, could happen. In spite of these difficulties, in almost all of the cases, the patients feel they have received some benefit both in vision and in the visual comfort. REFERENCES 1. Lindstrom RL, Hermann WK: Pupil capture—prevention and management. Am Intraocul Implant Soc J 9:201-04, 1983. 2. Gimbel HV, Neuhann TH: Development, advantages, and methods of the continuous circular capsulorrhexis technique. J Cataract Refract Surg 16:31-37, 1990. 3. Lavin M, Jagger J: Pathogenesis of pupillary capture after posterior chamber intraocular lens implantation. Br J Ophthalmol 70:886-89, 1986. 4. Bowman CB, Hansen SO, Olson RJ: Noninvasive repositioning of a posterior chamber intraocular lens following pupillary capture. J Cataract Refract Surg 17:269-80, 1991. 5. Brazitikos PD, Roth A: Iris modifications following extracapsular cataract extraction with posterior chamber lens implantation. J Cataract Refract Surg 17:269-80, 1991. 6. Raposo Fo A, Paiva Fo C, Paiva F: Complicações per e pós operatórias na cirurgia extracapsular e nos implantes intra-oculares. Arq Bras Oftalmol 50:124-29, 1987. 7. Ferraz Fo CPA, Davila BC, Belfort Jr R et al: Lentes intraoculars em uveítes. Arq Bras Oftalmol 50:199-202, 1987.

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Durval M Carvalho Durval M Carvalho Jr

IOL Scleral Fixation in Aphakic Eyes

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INTRODUCTION There was always a lot of controversy regarding the use of anterior chamber lenses for solving the aphakia cases or for scleral fixation.1 Objections to this latter were because it was a surgery that was done blindly; to the former because it could cause corneal endothelial cell losses in the long run and/or enhance the possibility of glaucoma. The anterior chamber lenses were strongly condemned in the mid 80’s. In the beginning they worked out well and were enthusiastically used. Over time, however, the progressive corneal endothelial cell loss always led to corneal decompensation and to corneal transplantation as a result.2-8 Dozens of models were tried and practically abandoned, except the Kelman’s quadriflex model that still could be found in the market. As long as it is correctly used, with the appropriate size and the right power,9 in a feasible eye, it can be a good option. However, in phacoemulsification surgeries, it is not always possible for one to foresee a loss of the capsular support. Therefore, the surgeon, when less expected, can be forced to use an IOL without support as a consequence of a luxation or a capsular loss. The patient today no longer accepts to leave the operating room without a reasonably good visual acuity. For such unexpected events it is difficult to keep a stock of anterior chamber lenses with sizes and variable powers with such little use. If the surgeon does not have good experience in scleral fixation he or she ends up placing an anterior chamber lens that is not the most appropriate for that situation. There are other options as it is the case of the iris fixation lens (Worst Claw).10

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This could also be a good option, but it requires a stock of lenses, a larger experience, and still produces doubtful results in the hands of those who do not have good experience. Such being the case, the scleral fixation should be the best option, because almost always the same planned lens can be used. It is accomplished with a very simple technique, further described. It is an including technique for all the cases, and as it is repeated it becomes easier and faster. The opportunities to do this surgery are few, and when they arise one would better apply the same technique for its optimization. INDICATION FOR SCLERAL FIXATION The frequency of the cases in which a scleral fixation surgery is needed varies from country to country. In developed countries the number of indications is smaller, because the patients undergoing cataract surgery, for some time now, has demanded IOL implantation. In some countries there are still many aphakic patients, as a result of extracapsular or even intracapsular surgeries, who have not yet been implanted with an IOL and who come to the hospitals for implantation. The frequency of traumas due to accidents and lack of protection during work also increases the need for scleral fixation. In our statistics, in frequency order, we have been doing scleral fixation in surgical aphakia, replacement of anterior chamber lens, traumas, luxated or subluxated IOLs, Marfan’s syndrome and others, and peroperative cases. In this chapter we will not discuss these indications, because we would have to discuss details that have nothing to do with phacoemulsification. We will discuss scleral fixation only in the cases in which a phacoemulsification with IOL implantation was planned and which required scleral fixation for not having capsular support. So, we will talk about those cases in which we tried and it was not possible to preserve the capsule as a support, or in the cases of syndromes in which we knew the capsular support would not be enough to hold the IOL. Nowadays, with several rings available for capsular support, scleral fixation has been avoided in the cases of partial zonulodialysis. We will not get into details as to how we usually solve our surgical difficulties in phacoemulsification complications, because that is a subject to be discussed in another chapter; this will be an analysis of the scleral fixation from the moment we decide for it. There are different instances that can interfere in the surgical strategy. Based on our own experience, it is important to have in mind: • Cases in which the capsular support was lost, but in which the surgery was accomplished without having to enlarge the clear corneal incision. • Cases in which the clear corneal incision was enlarged to introduce a glide of approximately 6 mm. • Cases in which a tunnel incision was enlarged for removal of the nucleus. • Cases in which it was necessary a large limbal incision for removal of the crystalline lens.

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INTRAOCULAR LENSES ADAPTED FOR SCLERAL FIXATION In the first phase of the surgeries for scleral fixation, the lenses were used according to readiness, a time when the use of the modified “J”-type lenses was frequent, but whose shape would not be the most appropriate today.11 In a second phase, specific lenses for scleral fixation were already available, produced in PMMA, and with a small ring in the internal face of the loop, in the place where the suture should be tied. We managed to design an IOL that was manufactured by Mediphacos, a Brazilian company, and in whose production and sale we do not have any financial interest. All PMMA, with a C-loop and a 7-mm optical zone, its total size is of 13.75 mm and it has two undulations in the internal face of each loop where the fixation suture is tied.

Fig. 39.1: IOL with ring on the haptic

Fig. 39.2: Durval’s IOL

Currently we consider this one-piece PMMA lens to be very rigid; difficult to handle inside the eye and only indicated in rare cases when a large incision is required. The C-loop seems to give a better stability, decreasing the tilting possibility. In the case of an IOL to be implanted in the ciliary sulcus it should be 13.75 mm in diameter in order to be well secured, mainly in big eyes.12 When the loops are made of flexible PMMA, the intraocular maneuver is made easier. However, the authors imagine that the polypropylene loops are more interesting because they cause more inflammatory reaction, which, after some time, causes them to stick to the ciliary sulcus, thus perpetuating their positioning.13 However, there is not yet a polypropylene loop with a support point on the loop to avoid slippage of the suture, as it is the case of the PMMA loops. When using polypropylene loops it is convenient to tie the suture firmly enough so that it will not slip from position. The 6-mm optical zone is very satisfactory since these lenses are fixated by the loops and they do not decentrate. There may be some tilting, but never a decentration. We have a fairly good experience with diffractive lenses in scleral fixation. Produced initially by the 3M style 815SL with 6 mm, they had flexible loops adequate for fixation. They would fit in very well and, due to the fixation itself, they would never descentrate. They were rigid but they are no longer available in the market.

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We avoided astigmatism by using tunnel incisions and referring the cases for complement refractive surgery. When it is well indicated, we have used the diffractive AmoAray lenses in some cases. They have silicon optical zones and flexible PMMA loops allowing for a good centration. We have been using the AcrySof lens in a large number of patients. Although they are good—we find them small (12.5 mm)— they may tilt when tractioned to the ciliary sulcus in big eyes. Currently, and based on our own experience, the ideal lens model for scleral fixation would be a 6-mm optical zone, acrylic or hydrogel lens, C-loop flexible naturally foldable, and diffractive in some cases, ranging in size from 13.50 to 13.75 mm and, if possible, with two small saliencies on each loop, at the farthest point from the optical center, in a very symmetrical way. SUTURES USED IN SCLERAL FIXATION As the scleral fixation is intended to be definitive, among the suture materials available in the market today, the recommendation relapses on the polypropylene suture. The most used has been 10-0 prolene suture. The 10-0 prolene suture is presented in a long and curved CIF-4 Ethicon needle (Catalog 788-Gr, Ethicon Inc.),34 adequate for scleral fixation, in a way such as to allow the insertion of the needle through the anterior chamber stab incision and its exit from outside the ciliary sulcus, emerging in the sclera.14-18 The 10-0 polypropylene, (20 cm straight-side cutting-double armed Alcon SC-5) is very much used. We prefer35 the 9-0 polypropylene suture, 30 cm 2 Atraloc 0.62 cm TG 140-6 Ethicon. It is a more resistant and firmer suture, which greatly facilitates its threading through the interior of the needle at the moment of the preparation. This suture has the following advantages: • It is easily passed through the hole of the needle because it is much firmer than the 10-0 suture, • It is safer for longer periods as described before, • Being thicker, it is less subject to breaking during the tightening procedures. USING VIDEOENDOSCOPY The ocular videoendoscope, coupled to the diode laser, works as a probe of optical fiber, of 0.94 mm, and is made up of three bunches of fibers. The first bunch is connected to the illumination system that takes light into the eye; the second is linked to a video system to produce, focus and record images. And the third, linked to a diode laser unit, is available when needed. In the last four years we have been using this equipment, accompanying its technological improvement. The scleral fixation, once a criticized surgery because it was done blindly, today is like any other ocular surgery. In the patients who have already undergone facectomy, we had some restrictions to indicate the scleral fixation due to the possibility of a definitive ocular hypertension after surgery. Nevertheless, now with the endocyclophotocoagulation, even in those borderline cases or even in glaucomas, we indicate the surgery because there is the possibility of solving both problems at the same time.19 The ECP (endocyclophotocoagulation)

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is performed soon after the placement of the lens, taking care so as not to photocoagulate the haptic, when this is blue. Photocoagulation of the ciliary processes before the placement of the IOL makes them retract, making them smooth and hindering a good positioning of the haptic in the ciliary sulcus. When we are to use cyclophotocoagulation, it is recommended to do at least in 180º, in the presence of more advanced glaucoma, at higher-pressure levels, a photocoagulation of 200º is recommended being necessary to enter with the ECP through two incisions via pars plana. It is not sufficient to photocoagulate the head of the ciliary process; it is necessary that all its body and the tail be done so that the proposed objectives are reached.20 As in these cases there is always a vitreous aggression, vitrectomy is recommended soon after ECP, taking advantage of the sclerotomies that receive the ECP and the vitrector to remove all the vitreous strands that could be stuck to the haptic or to the sclerotomies themselves. The irrigation should always be maintained in the anterior chamber by a maintainer. SURGICAL TECHNIQUE Introduction Not always the simplest technique is the fastest and the most effective one. Sometimes the attempt to simplify the technique may not yield the expected results. The operating time must not be forgotten. If we want to be successful in the scleral fixation, we should not overlook the following requisites. • Protection of the endothelium Fig. 39.3: Endocyclophotocoagulation • Removal of the vitreous • Needle pass through the sclera without causing injury to the iris and ciliary body and contact with the vitreous • Safe suturing on the IOL haptic • Burial of the knot in the sclera. This surgery aims at changing the aphakic into a pseudophakic patient, with minimal aggression to his or her eye, solving his or her problems in the shortest time possible, without immediate or late complications, and by offering him a better and more comfortable vision. Such results are obtained depending on the difficulty of the case and on the surgeon’s interest and experience. In special circumstances as the ones that lead the patient to this surgery, it is difficult a comparison between the techniques and the results. The more complicated the cases, the more individualized they are in their manifestations, and the best results depended on more opportunities and better information. However, it is difficult for the surgeon to make an evaluation, because each case is unique and will never be operated on by another surgeon in the same way.

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The scleral fixation should be planned with more emphasis than the other surgeries, because decisions need to be made every moment. The first great decision is on the surgical technique to be used, among the dozens of options available. Since Dr Malbran’s publication, in 1986,21 in which a 10-0 polypropylene suture was threaded through a 28 G needle, and the esclera was pierced at the 3 O’clock and the 9 O’clock positions to secure the IOL, several techniques have been developed etc.22,32-35 The possibility of so many options shows that none of them is ideal or that any one can solve the problem. Our intention was to choose a technique that could include all the cases so that its optimization could be obtained as we executed it, thus making it easier. It became our technique of choice for the following reasons: • Due to its simplicity • It demands nothing special, it is enough to keep a box of 9-0 prolene suture in stock • It can be used in the surgeries of every type of aphakia without capsular support • It allows the implantation of IOLs in aphakic eyes without breaking a still intact hyaloid. This is a great advantage because the statistics show that practically all retinal complications in scleral fixations occur in eyes partially or totally vitrectomized. There are cases of aphakic patients with an intact hyaloid, in which the scleral fixation can be made with results practically equal to that of a facectomy with an intraocular implantation in the ciliary sulcus. The crystalline ectopia syndromes, the luxations, and the intraocular facectomies can be mentioned as examples for these cases. • Another important reason is that the knot can be easily buried in the sclera, unlike most of other procedures. Strategy Once we have decided on the surgical technique to be used, we have to decide how to intervene: It is important to decide where the lens should be secured. It is convenient, insofar as possible, to move away from the 9 O’clock and 3 O’clock positions in order to avoid local vessels and long ciliary nerves. One should take other variables into account, like the choice of a site where the conjunctiva is not stuck to the sclera, on one or on both sides. When choosing the location for the lens fixation, it is important to find a point where the conjunctiva is free and thicker— as in the cases of thick pinguecula—so that when covering again the IOL-fixation point it becomes well protected. Another factor to be considered in this decision is the iris posterior space. Capsule debris is usually found in the periphery. Many times, the capsule remains can be used as support for the lens haptic, providing it with greater stability. Preparing the Sclera Once it is decided the location of the IOL implantation, it is time to get the sclera ready to receive the point which will secure the IOL. The conjunctiva is open by

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doing a peritomy of approximately 4 mm. In this technique it is not necessary to do the scleral flap as it is in others.23,32 One of the ends of this incision is extended radially, exposing and cleaning the scleral bed and doing diathermy to avoid hemorrhage. One millimeter from the limbus, in the site chosen for the fixation, a 1 to 2 mm scleral incision is made perpendicular to the limbus, trying to reach a depth of ¾ of the scleral thickness. The procedure is repeated on the other side of the eye, in an equally distant position. In these two areas the IOL haptics will be secured.

Fig. 39.4: Pulling away the conjunctiva

Fig. 39.5: Radial sclerotomy

Flieringa ring in the Scleral Fixation In some cases it is indispensable the placement of a ring to give support to the sclera, thus preventing the vitreous from being pushed towards the anterior chamber. This should be made whenever there is a need to hold the vitreous back. This prevents the eye from becoming very soft, making the job difficult and, mainly, when the incision is limbal and large, or even in some larger tunnel incisions. The conjunctiva is open in the chosen sites, then the two radial scleral grooves are created where the lens supporting sutures will be passed; the groove of the main incision is created to prevent the ring from hindering the movement of the conjunctiva. Using a needle with an 8.0 silk suture, the conjunctiva, the Tenon and the superficial sclera are grabbed at six points approximately the same distance from around the eye. These sutures are trimmed to a length of approximately 3 cm before the knots are made. One then places the ring that should be appropriate for that eye, that is to say, is big enough so as not to interfere in the handling of the prepared incisions. It should not be positioned very posterior to the eye. Of the six points, two should be placed close to the two small radial incisions. This detail is important to hold the sclera in that area where the needles will be passed through. Of course, the job is completed with four more points, two superiorly and two inferiorly. When the ring is placed, the two points are tightened, beginning with the two points close to the radial incisions. It would be better to leave the ring more posterior, superiorly, to facilitate the handling of the incision at the 12 O’clock position.

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Preparation of the Needle with the Suture The aim is to fixate the IOL by passing a suture through the posterior and anterior chambers. Among the different ways of doing that, one stands out for being simple, practical, fast, economic, and above all, effective. We prefer to use a 30 ½ gauge hypodermic needle, which is very fine and sufficiently perforating to lessen the aggression to the uveal tissue.

Fig. 39.6: Flieringa ring

Fig. 39.8: Aspirating the suture

Fig. 39.7: How to prepare the suture in the needle

Fig. 39.9: Threaded suture

This suture comes on two needles. The suture is cut in half and, holding the standard hypodermic needle with one of the hands, and with a delicate forceps in the other hand, the non-threaded end of the suture is placed in the lumen of the needle, starting from its sharp bevel and pressing smoothly so as not to fold it, until the end of the suture exits through the foot of the needle and can be pulled out with the forceps. When pushing a 10-0 prolene suture through the needle with the forceps it is likely to curve; but it does not happen when the 9-0 suture is used. The way we found to cope with this difficulty when using the 10-0 suture was to partially insert the suture in the needle, to dip it in a receptacle with BSS and, by using a syringe, to aspirate the suture together with the BSS. This way the suture will be passed at once and the needle of the 10-0 suture will touch the bevel of the hypodermic needle.

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The threaded suture is at one of the ends and inserted in the hypodermic needle at the other end. When inserting this needle in the eye, the suture enters together with part of it going inside and the other part lying outside the needle, without any risk of being cut by the bevel since it is leaning against the internal border of the lumen of the needle bevel that is not sharp. Passing the Needle through the Sclera The objective of this operating time is to pass a prolene suture through the sclera at the level of the ciliary sulcus where the IOL is to be fixated. The work of Althus C, Sundmacher R,36 making scleral fixation with the use of videoendoscopy, is categorical in showing the need to pass the suture exactly through the ciliary sulcus. Further we demonstrate that, in our own experience with videoendoscopy, we had cases in which the suture was not in the sulcus, even so we managed to place and secure the lens in the sulcus with good results. Of course it would have been better if the sutures had been placed in the sulcus. For those who do not use videoendoscopy there is a lot of controversy regarding the different techniques for this procedure. Some defend passing the suture from the inside to the outside, while others insist on doing it from the outside to the inside, closer to or more distant from the limbus there are those others, however, opt for a straight needle or for a standard hypodermic needle, with or without definition of the caliber. However, the ciliary sulcus can be visualized only when we use videoendoscopy. There are some variables that are worth mentioning: • According to Althus C and Sundmacher R36 1993, in a hypotensive eye the ciliary body is projected forward almost causing the ciliary sulcus to disappear. • The videoendoscope is an auxiliary tool not always available at the clinics or ophthalmologic hospitals. This is why it is a maneuver almost always done blindly. • When the suture is passed blindly, the possibility of it staying in the sulcus can vary a lot due to the inclination of the needle, be it 1, 1.5 or 2 mm away from the limbus.33 • The inflamed or recently operated eyes from another surgery are prone to hemorrhages during the transscleral suture procedure. • Hypotensive or inflamed eyes facilitate uveal detachment when the needle is introduced from the outside to the inside, as the authors have observed but not yet published. • The depth of the iris root in relation to the white of the sclera varies from person to person. And it is important to use it, as a guide in order to know how far from the limbus the needle must be positioned. The prolene suture 10-0 with the straight needle stc-6 Ethicon, Norderstedt, West Germany has the advantage of being very sharp, and easy to penetrate the sclera. A limitation, however, is the fact that it is only usable with the help of a needle holder or of forceps, thus limiting the surgeon’s movements. Since 1994 we have been using videoendoscopy in most of our cases of scleral fixation. When videoendoscopy is used, it is easier to enter the eye from the outside,

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because with one hand you introduce the needle and with the other you hold the video probe, visualizing and monitoring the passing of the needle through the ciliary sulcus. In the work of Althus et al, 1993, using videoendoscopy, they affirm that better results are obtained by passing the sutures from the outside to the inside with the eye still shut.

Fig. 39.10: With a straight needle

Fig. 39.12: Introducing the needle in the ciliary sulcus

Fig. 39.11: Needle in the ciliary sulcus

Fig. 39.13: The suture haptic is being exteriorized

Let us illustrate it with a case: we use a standard hypodermic needle previously prepared with a suture (polypropylene 9-0 30 cm, 2 Atraloc 0.62 cm, TG 140-6 Ethicon) passed through its lumen as already described. Carefully, for not unstringing the needle, we fold it with the fingers, making a larger or smaller curve according to the need to adapt to the available space in order to introduce it in the eye without the nose standing in the way; this on the nasal side, where the nose limits our movements. Holding it with the thumb and index finger allows us a total control of the movements of the tip of the needle. Through the small radial scleral incision previously prepared (see preparation of the sclera) we introduce the tip of the needle and hold it momentarily in this position while, with the other hand, we introduce the video probe through the clear cornea, trying to visualize the probable point of entrance of the needle in the ciliary sulcus.

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The monitoring of the transscleral needle pass that will guarantee the suture fixation in the ciliary sulcus is an easy and practical maneuver because, maintaining the eye pressure with a maintainer and some viscoelastic in the anterior chamber, the tip of the ECP is introduced in the main incision, generally at the 12 O’clock position. One of the hands introduces the threaded needle while the other is used to position the ECP. The procedure is repeated on the other side. This procedure, besides guaranteeing the correct positioning of the suture in the ciliary sulcus, allows the photocoagulation of the hemorrhages caused by the passing of the needle in that area; in almost always hypotensive eyes. Another plus in this technique is the possibility of preventing uveal detachment by pressing it against the sclera with the very optical fiber to allow the needle pass. When the endoscopic visualization shows that the ciliary process is being pushed into the eye, there is the option of retreating and redirecting the needle to the ciliary sulcus without loss of precision. When the needle with the suture emerges in the ciliary sulcus, it is possible to push it inside as far as the pupillary area, towards the anterior segment, without losing control at the Fig. 39.14: The suture haptics completely exteriorized same time that you pull back and remove the videoendoscope. Since the needle is partially bent, we can bring it close to the clear corneal incision and then pull it back 1 to 2 mm. This retreat allows loosening the suture that was stretched inside its lumen, thus making a haptic that can be easily pulled by a hook through the clear cornea until it is exteriorized. This exteriorized haptic should still be held with the hook until the needle is drawn back and slowly removed from the eye so that the suture comes out of its lumen. It is not infrequent, when removing the needle, to pull the suture together and undo the whole service. By using a viscoelastic substance, like sodium hyaluronate, and with a total control of the needle, the hyaloid can be pushed without manipulating the vitreous. It is very useful, mainly in the cases of ectopia lens syndromes. When passing the needle through the sclera, from the outside to the inside, it is convenient to be attentive to the ocular pressure. If the eye is soft, the penetration of the needle provokes a scleral depression and a consequent tension on the uvea that leads to its detachment, mainly when there is inflammatory reaction with edema. At times it is necessary to use the videoendoscope tip or another instrument to force the uvea against the needle so it can be perforated. Hemorrhages are also frequent in these hypotensive eyes. This event should be considered in the surgical planning. We have two available resources to maintain the eye hypertensive during this surgical maneuver: first, the viscoelastic with a higher concentration and, second, the continuous irrigation with a chamber maintainer.

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The authors usually make use of the two. They place the maintainer in the inferior limbus, leaving the BSS bottle at the level of the patient’s head and filling the anterior chamber with viscoelastic. After introducing the video probe and preparing to enter the sclera with the needle, they have the BSS bottle raised to a height that keeps the eye not exaggeratedly hypertensive until the needle has crossed the uvea. Afterwards, it is lowered to the level of the eye for the probe to be removed and the suture haptic to be pulled without risk of causing iris prolapsed. In cases of hemorrhages we can keep the eye hypertensive for some time. For this reason, and whenever possible, in the cases that require large limbal incision, it is better to make a small incision, place the sutures and then enlarge the incision. Otherwise, you can make the incision, remove the cataract, and close the incision temporarily with an 8-0 silk suture and, after passing the sutures you can open it enough for the insertion of the lens, before suturing again with the 10-0 mononylon suture. We also avoid using videoendoscopy in the cases with intact hyaloid, what would be an additional risk factor of breaking, since the lens is generally very well positioned by the own force of the vitreous. When the videoendoscope is not used, the needle is held between the fingers to make it penetrate that previously prepared radial incision into the limbus. At first, this is done perpendicular to the root of the iris until it has entered the eye. The tip of the needle is then turned parallel to the posterior surface of the iris and, slowly, visualizing the saliency in the iris caused by the tip of the needle, the movement is completed without sticking the iris posterior face. By lifting the tip of the needle without pushing, one can see the saliency in the iris and turn back down enough to push a little more to the front. The movement is repeated until the tip of the needle emerges on the pupillary border, close to the posterior surface of the iris. In the cases in which there was no previous vitreous loss, and with an intact hyaloid, this maneuver allows passing the sutures without breaking it. When curving the needle they prefer that the bevel is on the concave surface of the curve so that it can enter the incision parallel to it, thus facilitating the entrance in the sclera and presenting smaller hemorrhage risk at the level of the ciliary body. Once the needle is placed inside the eye this position allows the movement of the bevel upward, avoiding traumas to the iris, and allowing for visualization of the suture, which is already stretched and close to the most posterior part of the bevel. The Incision in the Scleral Fixation In the surgical planning, the type of incision to be used is important. In the cases of crystalline syndromes or in other cases where there is the possibility of finishing the aspiration and cleaning of the lens material through the clear corneal incision, a foldable lens, be it acrylic or silicon, could be used without necessarily changing the incision.34 It may not be interesting to place a foldable lens in an eye that already has a large incision. A situation is dependent upon the other.

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The tunnel incision is also a good option for the scleral fixation surgery. Its great advantage is that you can do the piercing and the threading of the sutures after all the preparation of the eye is finished; because even being large the incision is enough self-sealing to create a positive pressure the moment the suture is passed. Using this type of incision will depend on the technique that the surgeon is using during the phacoemulsification, and on the moment he or she is forced to shift from the phacoemulsification to an extracapsular surgery. For example: When the nucleus is already fragmented, or small enough to be removed through the incision in tunnel, it is enough to enlarge it or to enlarge a clear corneal incision so that these nucleus fragments can be taken out. This incision can be used for the scleral fixation afterwards. Preferably, we make the clear corneal incision a little behind the limbal vascular arcade. To shift into a tunnel incision it is enough to extend its edges obliquely towards the posterior pole, making a tunnel in frown, with a larger or smaller bias according to necessity. The intraocular maneuvers through this incision are difficult and, for this reason, it will always be necessary to make two side ports for irrigation and vitrectomy or for irrigation and removal of the viscoelastic substance. This type of incision is very useful in the cases of IOL replacement. The limbal incision has lots of inconveniences. However, in the cases in which there is luxation of the cataract, even after a clear corneal incision has been tried, it is better to shift to a limbal incision to facilitate the cataract removal through a large incision and then to be able to enlarge it during the extraction, if it is necessary. Nowadays we use perfluorocarbon after vitrectomy to lift the cataract up to the pupillary plane in the cases of luxation, and then proceed the phacoemulsification there. This has greatly reduced the need for limbal incision. A great disadvantage of this incision is that it is not advisable to try to place the sutures through the sclera with the eye open. To avoid this, one would have to close the eye with a temporary suture, increasing the surgical time. Currently, we place the scleral fixation sutures before shifting from a clear corneal to a limbal incision. Another difficulty is that with this type of incision the eye gets very soft, and in order to have a better support it is advisable the placement of a Flieringa ring, which also increases the operating time. The way we do it, starting from a clear corneal incision is as follows: when the conjunctiva is slack, a peritomy of the size planned for the incision is done. Pulling the conjunctiva away is enough, without disinsertion of the Tenon. The size of the incision will depend on the case. After pulling away the limbal conjunctiva, we make a superficial groove all along the planned extension by cutting the superficial limbal vases. This groove will allow bleeding and vascular retraction, making spontaneous homeostasis, and marking the site of the incision in order to prevent blood from entering in the eye when we open the anterior chamber. Using a 1 mm diamond knife we enter through the clear corneal incision as we extend it vertically. One enters the limbus a little posterior to the capillary loops, looking for a hard tissue and not the spongy scleral tissue. With the blade, one tries to enter vertically,

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almost perpendicular to the iris plan, using the groove previously made. A diamond knife is carefully used so as not to do, at the same time, a peripheral iridotomy. In order to avoid any further harm to the balance of the suture, diathermy is avoided. The limbal ring is still maintained in spite of the large incision. How to Place the Suture to the IOL It is necessary to prevent the IOL from touching the external surface of the cornea or of the conjunctiva to avoid contamination during the surgical procedure. I have been using a circle of spongy plastic, cut out of the material that comes in the suture package. Having about a 5 mm diameter, it is placed on the cornea to support the IOL until it is tied by its haptics. Now the two bent sutures must have already been passed through the sclera, at the level of the ciliary sulcus, and exteriorized through the main incision. At this phase of the surgery we will already be with two double sutures exteriorized in the clear cornea. And if we are to use a lens with rings already placed at the points of balance of the lens, it is enough to pass the haptic with the bent suture through the inside of the ring and to lasso the end of the lens haptic. We have designed another type of lens specifically for use in this technique, as mentioned previously. It has two saliencies in the internal face of the haptics,

Fig. 39.15: The suture being tied to the haptic in a Durval’s IOL

at the exact point of balance. The suture should be lassoed at that point, in a quite fast way. The drawing shows how to tie the suture to the haptic. When we use common lenses such as the acrylic,34 the silicon or the PMMA ones, it is necessary: • To choose the farthest point of the haptic to tie the suture, in balance with the point of the other haptic.

Fig. 39.16: The suture being tied to the lens

Fig. 39.17: The suture in a simple haptic

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• That we place three simple knots making sure to carefully tighten mainly the first knot well so that it does not slip through the haptic. This is easy because the 9-0 suture resists the traction well. It must be pointed out that we place these knots using the sutures bent, which provides an area of larger contact between the suture and the haptic. • To have the care of leaving the suture in the external face of the haptic in the position that will be inside the eye. To do that, it is enough to hold the IOL haptic and to stretch the suture so that it is positioned. • To make up time. We first place a simple knot without the presence of the lens. We leave the knot small enough to allow easy introduction of the haptic through it. It is then tightened. Hence forward it is easier to place the other knots. In the implantation of foldable lenses through a clear corneal incision, a haptic is tied first and then the lens is introduced in the eye. One must be attentive to the way of tying the lens with the forceps, because the tied haptic has to be the first to enter the eye, and only after that the second haptic is tied and introduced. With lenses introduced by cartridges of the AmoAray type, we push the lens slowly until the haptic partially comes out of the cartridge; enough to be tied. After that, by pulling the scleral sutures we guide the haptic to its intraocular position by pushing it with the cartridge until liberating it totally. Finally, the second haptic is tied and introduced. IOL Placement in Scleral Fixation The insertion of the IOL is the highlight of the scleral fixation surgery. Even in the cases in which the suture passes through the middle or posterior to the ciliary processes, it is possible to implant and secure the IOL in the ciliary sulcus, mainly when a 13.75 to 14 mm lens is used. The heads of the ciliary processes vary in size from individual to individual. Some are so big that they would be enough to hold the haptics placed in the ciliary sulcus without fixation. It is important to place the haptics in the ciliary sulcus. This procedure is relatively easy with the first loop, increasing the degree of difficulty during the maneuver to place the second haptic. The one-piece lenses are less flexible and, considering that most of the times a good mydriasis is not available, the movement of passing the second haptic to the back of the iris causes tension on the first, forcing it to erode from the ciliary sulcus. Monitoring of the IOL insertion is a more difficult procedure. We have made this possible in some cases with the help of another surgeon. While one introduced the IOL, the other maintained the tip of the ECP through the pars plana, monitoring the dynamics of its placement in the ciliary sulcus. This was very important to show that, many times, after we have already placed the first haptic in the ciliary sulcus, and when inserting the second haptic the first one is pushed posterior to the ciliary body. Then when one tries to reposition it by pulling the external sutures the haptic pushes and kneads the ciliary process and its repositioning in the anterior part fails. As this visualization is not routine, the practical thing is, after having

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implanted the lens, to do a revision, introducing the ECP to visualize the correct positioning of the lens under the iris or the presence of some vitreous strand on the haptic or on the suture. When examining, with the ECP, the cases in which the lens is tilted we have detected: • Inadequate positioning of the haptic, because the transscleral fixation suture was not exactly in the ciliary sulcus • Inadequate positioning of the haptic, because, in spite of the sutures having been passed through the ciliary sulcus, the haptic was positioned inferior or obliquely to the ciliary process • Remains of cortical material making lever on the haptic; or fibrosis • Remains of the capsule synechiae to the iris that push the haptic • The end of the stem stuck in the iris or in some vitreous strand • Badly positioning of the knot on the haptic • Small lens tractioned by the sutures. It can be improved to lessen the tension of the sutures on the lens. The use of videoendoscopy has evidenced that IOL replacement is difficult when the haptic goes behind the ciliary processes without its complete removal from the eye. On trying to pull the suture, the haptic is dragged upward, pressing the entire ciliary body. If the tissues were resistant, the traction of the suture would make the IOL slide over the heads of the ciliary processes. In this case, however, the tissue is compressed under the haptic. Without videoendoscopic visualization, this fact goes unnoticed and must be quite frequent and, probably, responsible for unknown consequences. Would it affect the ocular pressure? These problems are avoided by introducing the lens slowly in the anterior chamber and sliding it close to the posterior surface of the iris so that it is fit in the ciliary sulcus. This is done always by tractioning the sutures. After it has been positioned, an assistant should keep the fixation suture of the first haptic stretched, thus preventing the haptic dislocation from its position. Then, very carefully, the surgeon can introduce the second haptic, sliding over the posterior surface of the iris—until he or she feels that he or she is in the ciliary sulcus—and then pulling slightly the suture. Once the two haptics are positioned in the sulcus, there is no longer the risk of dislocation. When the incision is small and the lens is introduced very tight in straight line, one does not have good control of the forceps to turn the lens and get the haptic in the position for the transscleral suture fixation. When rotating the lens to position it, the first haptic can press the ciliary processes or be positioned behind them or obliquely. This is another factor that should be taken into account when planning the surgery and selecting the site of the radial incisions in the sclera. For example, if the main incision is placed at the 12 O’clock position, the fixation point of the first haptic should be between the 7 O’clock and the 8 O’clock position. When it is noticed, therefore, that the haptic is not in the sulcus, it is advisable to use a hook to put it there. It is not ease. In the case of a foldable lens, it is advisable to position the first haptic correctly before securing the second haptic.

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When using lenses with a ring on the haptic, one can use the Carvalho’s maneuver to place the second haptic. It consists in entering with a Sinskey hook through a paracentesis, exiting through the main incision, securing it to the haptic small ring, pulling it into the eye and, finally, positioning it within the ciliary sulcus without forcing the first haptic downwards. If a haptic is oblique in relation to the ciliary sulcus, in spite of the sutures being in the sulcus, the ciliary processes will function as a lever, tilting the lens. Its replacement becomes difficult, because the ciliary body has the consistency of a sponge and the haptic creates an oblique depression in its center. When trying to bring the haptic upward, the ciliary process gives off, and when the surgeon lets it off it goes back to the original position. Althus et al, 199336 state categorically that the haptic should be directed to the sulcus and secured there, and we fully agree. Suture Fixation in the Sclera At this point of the surgery the lens is already placed in the eye, with the haptics positioned within the ciliary sulcus and two sutures on each site; one of which is threaded and the other is not—on each side exiting through the small radial incisions close to the limbus. The threaded suture is passed from the inside to the outside, on the border of the small scleral incision made previously and, then, from the outside to the

Fig. 39.18: Carvalho’s maneuver

Fig. 39.19: Burying the knot

inside, giving a buried knot. With the other suture, which exits from the lens haptic, burial of the knot is completed. After placing three simple knots, and using a blade, the sutures are trimmed short enough to be well buried within the small incision. Over time, the traction of the lens itself tends to bury them definitively. Only a curve of the knot is left at the level of the scleral surface, and which will be covered by the conjunctiva which, by its turn, will be repositioned with a knot of a 10-0 absorbable suture at the end of the surgery. Since it is a small incision, one runs the risk of cutting the suture when passing the sharp needle, mainly when the 10-0 suture is used. In cases that require vitrectomy, it is recommended to position the sutures but not

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to complete the knots until the end of the surgery, as the lens can dislocate, thus calling for replacement. It is also important not to overtighten the knots, because it can cause tilting of the lens, mainly in the case of small-sized foldable lenses. Good sense will indicate the point of stability and of balance. Removal of the Viscoelastic Substance As we are usually with the chamber maintainer installed, aspiration of the sodium hyaluronate should be very cautious trying to keep the balance between aspiration and BSS inflow. We use a cannula with a syringe to have better control of aspiration. When a vitreous strand is noticed in the anterior chamber, it is immediately removed by using the vitrector and, if necessary, a vitrectomy is done underneath the lens. The clear cornea is usually used for insertion of the vitrector. Closure of the Eye A closing type is chosen for each incision type. The clear corneal cases are sometimes sutureless or a 10-0 absorbable suture is used to maintain the coalescence during some days. In some cases, it can also be necessary a buried stitch with an absorbable suture in the side port—where the chamber maintainer was placed—in spite of being a beveled incision. The procedure is the same both for the tunnel incisions and for the side port incisions. The option is for a continuous interlocking suture in the main incision, very long in the scleral bed to guarantee good support. Since they are self-sealing incisions, a 10-0 absorbable suture, not very tight, can be used so that it is the most physiologic possible, preventing scleral slippage that can lead to astigmatism. In sclerotomies, sometimes used by the videoendoscope or by the vitrector, the 80 nylon suture is used with an X-point as usual. If necessary, the conjunctiva is closed with a 10-0 absorbable suture, always making a conjunctival covering on the fixation points in the sclera. Limbal Incision Suture Since 1986 we have used a suture technique appropriate for limbal incisions in which we use a 10-0 mononylon suture attached to a 5.5 or 6.5 mm needle. We start on the left side of the incision by introducing the needle from the inside and exiting the sclera 1 mm from the edge. The needle is introduced in the cornea again, 1 mm from the border, exiting within the incision in the same direction of the scleral suture so as a buried stitch is obtained. It is necessary to be attentive to make the needle exits through the left side of the stitch so that it matches the foot of the suture to which it will be knotted to close the point. Without cutting the suture to place the knot, one takes advantage of the needle held in the needle holder and the second stitch is started farther ahead, of course. It is recommended that, when entering the incision and exiting the sclera to catch

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the needle, the suture be left completely to the left of the needle holder so that it is not entangled. Then, in order to complete the stitch, one enters the cornea and exits through the incision. When retaking the needle inside the incision, it is necessary to leave the entire suture to the right of the needle holder so that the two ends are only to one side of the knot. Then the needle is pulled until a haptic is between two stitches. This suture should be long enough to be cut into two threads, one for each stitch, making pair with each other and allowing for the creation of two separate stitches that should be buried automatically. A series of stitches are placed, as many as necessary, looking like a continuous suture and always with a larger haptic between two stitches. Once the last stitch is placed, the needle holder is put aside and, using a scissors, all of the haptics are cut. This work will be a sequence of not-yet-knotted stitches, with the two ends of the suture always on the left of the knot. The amount of loosen sutures cause certain confusion, but this type of suture has the following advantage: when cutting the suture haptics, the ends are left with a nice length for placing the knots and, being straight and directed upwards, they make easier the manipulation of the forceps. In this procedure the suture remains untouched, unlike the other techniques in which it ends up elongated and rolled up.

Fig. 39.20: How to start suturing

Fig.23.22: Cutting off the haptics

Fig. 39.21: Completing the knot

Fig. 39.23: The slit-knot

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Since it is a very abrupt incision, it becomes possible to know the depth of the stitch, inserting them some deeper and other more superficial, thus allowing for a perfect coalescence in the suture. The slit knot is a technique that applies very well to this type of suture, because, when working within the incision, the tightening of the sutures can be dosed through the closing of the ends of the incision. As it is a fast suture, several stitches can be placed (10 or 12 stitches, in a 9 mm to 10 mm length incision), what will facilitate the coalescence. The ends are cut with a blade inside the incision and very close of the knot, thus facilitating its burial. In other procedures, the burial of the knot demands stretching of the thread, consequently loosening the suture or breaking up the thread, what hinders the control of a good coalescence. In the case of astigmatism, which is usually low, such stitches can be removed little by little postoperatively to a limit thought to be ideal, without the risk of greatly inverting the astigmatism by removing a stitch when they are few. Vitrectomy in Scleral Fixation When beginning a scleral fixation the surgeon should have a vitrector on hand. The most common model today has a guillotine-like tip, which in my point of view not always is an advantage for the surgeon of the anterior segment who sometimes needs to work close to the iris-corneal recess. Another disadvantage is the difficulty in cutting fibroses in the anterior chamber, at times inelastic membranes that will not come through the opening of the vitrector. We would rather use vitrectors with the oscillatory rotating tip, with an opening on the end and that totally cuts the vitreous without provoking traction causative of retinal detachment, and that also allows the removal of vitreous strands in any part of the anterior chamber. In our own experience in scleral fixation, complications in the posterior segment appear more frequently when there is vitreous loss or when a vitrectomy has been done previously. One of the most frequent situations, seen through videoendoscopy, is the vitreous strands that accompany the fixation sutures and get trapped in the ciliary sulcus at the point of the transscleral fixation. These vitreous strands will always serve as support so that fibroblasts form fibrous cords, keeping traction; generating retinal reactions and other alterations of the posterior segment like cystoid macular edema (CME). There are several circumstances that require vitrectomy: • For instance, when one tries a scleral fixation without manipulating the vitreous and, at the end, on aspirating the viscoelastic substance there appears a vitreous button. With the vitrector in the anterior chamber, a well-balanced irrigation is maintained, a careful vitrectomy is done, and the fibers in the anterior segment are completely removed. The vitrector is withdrawn and irrigation is maintained with the maintainer. Then an air-bubble or BSS is injected with a fine cannula, while the maintainer is removed from the chamber to prevent a new vitreous prolapse. If there is no risk of hemorrhage, some myotics can be added to the

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BSS to avoid decompression of the anterior chamber when withdrawing the maintainer. • When the hyaloid is already broken and there is a lot of vitreous in the chamber. Depending on the case, the sutures can either be or not be passed before the vitrectomy without hindering manipulation of the vitrector. The alternative would be a very large anterior vitrectomy, removing the vitreous mainly from the area where the sutures are to be passed. In these cases, it must be pointed out the importance of the Flieringa ring. Irrigation, always separated from the vitrector tip, is done in the anterior chamber with the maintainer to avoid hydration of the vitreous. When the vitrector is withdrawn, the anterior chamber is kept filled with BSS until viscoelastic is injected to hold the vitreous behind. The anterior chamber is completed with Healon, while irrigation is decreased. The lens is then implanted and, when aspirating the viscoelastic, the maintenance of the pressure in the anterior chamber is guaranteed to prevent the vitreous from coming forward. If there is still vitreous the anterior segment, even after the lens has been positioned, irrigation is maintained with the maintainer, and the vitrector is introduced from behind the IOL through a side port incision, unless it is a limbal incision. In that case, one enters between two stitches and, behind the lens, a very wide anterior vitrectomy is done, trying to clean mainly the areas of the haptic fixation by bringing the mouth of the vitrector close to the fixation points so that—although there is still remains of entrapped vitreous—it is isolated from the vitreous body so as not to cause traction. In this phase of finish of the surgery, introduction of the vitrector through either clear corneal or tunnel incision should be avoided, because these incisions allow decompression of the eye, favoring vitreous prolapse in the incision and demanding more time for its repair. An alternative would be introducing the vitrector via pars plana, which is naturally the ideal procedure for a good cleaning of the entrapped vitreous strands. However, there is the disadvantage of having to make another incision and the risk of leaving vitreous in the vitrectomy incision —also frequently observed through videoendoscopy—when withdrawing the vitrector. • In the cases in which there is cataract, nucleus or IOLs debris fallen into the vitreous cavity, it is necessary a large vitrectomy. Attempts to remove those bodies are not recommended, unless they are completely loosen, under risk of complications for the retina. The retinal surgeon usually makes three incisions via pars plana: one for irrigation, another for illumination, and a third for the vitrector. As the communication between the anterior and posterior segments are now evident, one can opt for the irrigation with a maintainer of the anterior chamber, making a smaller incision in the posterior segment and, consequently, making the surgery faster, although this alternative hinders a little the placement of the vitrectomy lens on the cornea. Placing the maintainer of the anterior chamber and making two pars plana incisions, one for the vitrector and the other for the videoendoscope can also use videoendoscopy. It requires certain training for the surgeon to use his or her two hands. Although they are already vitrectomized eyes, it is important

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to do a careful revision at the end of the surgery in order to prevent vitreous strands from remaining in the anterior segment, suggesting the need of complemental vitrectomy. • When, due to glaucoma, one already plans to do the scleral fixation combined with an endocyclophotocoagulation, or when cataract pieces are seen dispersed at the vitreous base, the two pars plana incisions are prepared so that with the use of a videoendoscope and of the vitrector, a vitrectomy can be done, removing the impaired vitreous. Maintenance of the pressure is guaranteed through the anterior chamber. Endocyclophotocoagulation should be done before the vitrectomy. The cases in which we did vitrectomy, implanted the IOL, and then did the photocyclocoagulation, presented an exacerbated inflammatory reaction, unlike when we did the vitrectomy after endocyclophotocoagulation. A larger number of these cases are necessary for a better evaluation. The ideal would be to monitor the vitrectomy with the ECP to allow removal of the vitreous strands that are entrapped in the area of the haptics fixation. This can be made if two pars plana incisions are made. It is always necessary to consider the advantages and the risks. Complications in Scleral Fixation As this surgery, like any other, is repeated, it is optimized. As it is usually done in complicated cases, most of the complications sometimes appear as a consequence of the case itself.37,39 In our own experience, what appears more frequently in this technique is: • IOL tilt The causes have already been explained previously. The lens is usually in the same position in which it was left during the surgery. When the haptic is placed oblique to the ciliary process, it is common for the head of the ciliary process to work as a lever, preventing the lens from coming into position without being totally drawn away from the area. Through the reflex of the microscope on the lens it is easy to know how it is positioned. The difficulty is to have the disposition to remove it and to position it correctly when needed. The astigmatism caused by these tiltings is not very high because the lens is submerged in a liquid. • Glaucoma40 Three situations should be considered: first, the cases with normal IOP in which the posterior capsule was broken during a phacoemulsification and a large number of particles lodged in the vitreous base unchaining an ocular hypertension postoperatively. Our procedure, depending on the severity of the case, has been to intervene at the end of the second week, doing a vitrectomy with the use of the videoendoscope. Another situation is the large incisions in eyes without vitreous in the anterior chamber, with IOP at borderline levels and that later become hypertensive. The solution would be first to try to control with medication, and only then, in the case of failure, the endocyclophotocoagulation would be tried. A third situation is the glaucomatous eyes, badly controlled by medication, case in which we indicate endocyclophotocoagulation concomitant with scleral fixation.

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• Hyphemas and vitreous hemorrhages In the case of a hypotensive eye it is very frequent to occur a hemorrhage when passing the needle through the sclera. The blood can either stay in the anterior chamber or go to the vitreous. The time of recovery will depend on each case. In these cases, myostatic should be avoided in the anterior chamber. • Fixation of the root of the iris Even using videoendoscopy it is common for the transscleral needle to reach the root of the iris. There is a tendency of entering more anteriorly in the sclera, and if the iris gets stuck, there will be a small pupillary dislocation. Caution is needed to avoid this occurrence. • Cystoid macular edema (CME) As the surgical technique improves, the CMEs tend to disappear. The operating time probably begins to decrease and less vitreous gets stuck in the anterior segment. • Retinal detachment It is more directly related to vitrectomy and also to the case in itself than to the scleral fixation. The vitreous trapped in the anterior segment would be an aggravating factor. A good advise is to take care and not let any vitreous hold on the iris and in the ciliary sulcus. • IOL luxation It is likely to happen in this technique, when placing the lens scleral fixation stitch. One can cut the suture headlessly. When the haptic is very well positioned, perhaps, it could be left there. • Endophthalmitis31 As it is usually a surgery of much manipulation, it is important to have greater precautions. For instance, to clean the surface of the eye well with polvidine and avoid, as much as possible, that the lens to be implanted has contact with the cornea or the conjunctiva. • Corneal decompensation It rarely occurs when this technique is used. With much care there is practically no aggression to the cornea. The facectomy in itself is a possibility, or in the cases in which the cornea was already damaged and has an ocular hypertension. REFERENCES 1. Lyle WA, Jin JC: Secondary intraocular lens implantation—anterior chamber vs posterior chamber lenses. Ophthalmic Surg 24:375, 1993. 2. Apple DJ, Mamalis N, Loftfield K et al: Complications of intraocular lenses—a historical and histopathological review. Surv Ophthalmol 29:1, 1984. 3. Busin M, Arffa RC, McDonald MB et al: Intraocular lens removal during penetrating keratoplasty for pseudophakic bullous keratopathy. Ophthalmology 94:505, 1987. 4. Apple DA, Mamalis N, Olsen RJ et al: Intraocular Lenses: Evolution, Designs, Complications, and Pathology. Baltimore, Williams & Wilkins, 1989. 5. Pollack FM: Pseudophakic corneal edema—an l 1-year study of its development, incidence, and treatment. Cornea 8:306, 1989. 6. Brady SE, Rapuano C J, Arentsen JJ et al: Clinical indications for and procedures associated with penetrating keratoplasty, 1983-1988. Am J Ophthalmol 108:118, 1989. 7. Solomon KD, Apple DJ, Mamalis N et al: Complications of intraocular lenses with special reference to an analysis of 2500 explanted intraocular lenses (IOLs). Eur J Implant Refract Surg 3:195, 1991. 8. Lim ES, Apple DJ, Tsai JC et al: An analysis of flexible anterior chamber lenses with special reference to the normalized rate of lens explantation. Ophthalmology 98:243, 1991. 9. Trimarchi F, Stringa M, Vellani G et al: Scleral fixation of an intraocular lens in the absence of capsular support. J Cataract Refract Surg 23(5):795-97, 1997.

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10. Menezo JL, Martinez MC, Cisneros AL: Iris-fixated Worst claw versus sulcus-fixated posterior chamber lenses in the abdsence of capsular support. J Cataract Refract Surg 22(10):1476-84, 1996. 11. Davison JA: A short haptic diameter modified J-loop intraocular lens for improve capsular bag performance. J Cataract Refract Surg 14(2):161-66, 1988. 12. Davis RM, Campbell DM, Jacoby BG: Ciliary sulcus anatomical dimensions. Cornea 10(3):224-28, 1991. 13. Apple DJ, Mamalis N, Brady SE et al: Biocompatibility of implant materials—a review and electron microscopic study. Am Intraocular Implant Soc J 10:53, 1984. 14. Stark WJ, Goodman G, Goodman D et al: Posterior chamber intraocular lens implantation in the absence of posterior capsular support. Ophthalmic Surg 19:240, 1988. 15. Vajpayee RB, Angra SK, Sandramaouli S et al: Direct scleral fixation of posterior chamber intraocular lenses using a special needle-holder. Ophthalmic Surgery 23, 1992. 16. Hahn TW, Kim MS, Kim JH: Secondary intraocular lens implantation in aphakia. J Catarct Refract Surg 18: 174-79, 1992. 17. Rehany U, Rumelt S: A Transcorneal modification for scleral fixation of posterior chamber intraocular lenses. Ophthalmic Surgery 24(2):113-16, 1993. 18. Santos RWL, Neostein I, Agmont W et al: Nova técnica de fixação de LIO de câmara posterior—descrição de 22 casos. Arq Bras Oftal 53(5): 236-40, 1990. 19. Uram M: Combined phacoemulsification, endoscopic ciliary process photocoagulation, and intraocular lens implantation in glaucoma management. Ophthalmic Surg 26:346-52, 1995. 20. Carvalho DM, Paranhos FRL: Implante Secundário de LIO da Câmara Anterior: Fixação Escleral. Revista Brasileira de Oftalmologia 52:17-21, 1993. 21. Malbran ES, Malbran E Jr, Negri L: Lens guide suture for transport and fixation in secondary IOL implantation after intracapsular extraction. Int Ophthalmol Clin 9:151, 1986. 22. Hu BV, Shin SH, Gibbs KA, et al: Implantation of posterior chamber lens in the absence of capsular and zonular support. Arch Ophthalmol 106:416, 1988. 23. Lewis JS: Sulcus fixation without flaps. Ophthalmology 100:1346, 1993. 24. Eifrig DE: Two principles for repositioning intraocular lenses. Ophthalmic Surg 17:486, 1986. 25. Dahan E, Salmenson BD, Levin J: Ciliary sulcus reconstruction for posterior implantation in the absence of an intact posterior capsule. Ophthalmic Surg 20:776, 1989. 26. Girard LJ: Pars plana phacoprosthesis (aphakic intraocular implant)—a preliminary report. Ophthalmic Surg 12:19, 1981. 27. Dahan E: Implantation in the posterior chamber without capsular support. J Cataract Refract Surg 15:339, 1989. 28. Stark WJ, Gottsch JD, Goodman DF et al: Posterior chamber intraocular lens implantation in the absence of capsular support. Arch Ophthalmol 107:1078, 1989. 29. Lindquist TD, Agapitos PJ, Lindstrom RL et al: Transscleral fixation of posterior chamber intraocular lenses in the absence of capsular support. Ophthalmic Surg 20:766, 1989. 30. Shapiro A, Leen MM: External transscleral posterior chamber lens fixation. Arch Ophthalmol 109:1759, 1991. 31. Heilskov T, Joondeph BC, Olsen KR et al: Late endophthalmitis after transscleral fixation of a posterior chamber intraocular lens. Arch Ophthalmol 107: 1427, 1989. 32. Lewis JS: Sulcus fixation without flaps. Ophthalmology 100:1346, 1993. 33. Richard JD, Edward JH, Peter JA et al: Anatomic study of transscleral sutured intraocular lens implantation Am J of Ophthalmology 108:300-09, 1989. 34. Yusuke Oshima, Hitoshi Oida, Kazuyuki Emi: Transscleral fixation of acrylic intraocular lenses in the absence of capsular support through 3.5 mm self-sealing incisions. J Cataract Refract Surg 24, 1998. 35. Anthony JL, Edward JH,Woodford SVM et al: Histologic study of eyes with transsclerally sutured posterior chamber intraocular lenses. Am J of ophthalmology 110:237-43, 1990. 36. Althus C, Sundmacher R: Intraoperative intraocular endoscopy in transscleral suture fixation of posterior chamber lenses—consequences for suture technique, implantation procedure,and choice of PCL design Refract Corneal Surg 9(5):333-39, 1993. 37. Leatherbarrow B, Trevett A, Tullo AB: Secondary lens implantation—incidence, indications and complications. Eye 2:370-75, 1988. 38. Hayward JM, Noble BA, George N: Secondary intraocular lens implantation—eight-year experience. Eye 4:548-56, 1990. 39. Adam R, Bohnke M, Korner F: Results of posterior chamber lens implantation with trans-scleral sulcus suture fixation. Klin Monatsbl Augenheilkd 206(5): 286-91, 1995. 40. Kooner KS, Dulaney DD, Zimmerman TJ: Intraocular pressure following secondary anterior chamber lens implantation. Ophthalmic Surg 19:274, 1988.

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Amar Agarwal Athiya Agarwal Sunita Agarwal

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INTRODUCTION Since Charles Kelman started phacoemulsification, various new modalities have developed which have made this technique more refined. One problem still persists which is the size of the incision. The normal size of the incision is 3.2 mm. With time and more advances in phaco machines and phaco tips this reduced to 2.8 mm and then to 2.6 mm. Today certain phaco machines like the Alcon’s Legacy and the STAAR phaco machine have produced a 1.9-mm phaco probe. In other words cataract surgery has now commenced utilizing a sub 2-mm incision. The author (Sunita Agarwal) worked on laser cataract surgery and have achieved cataract removal through an incision below 2.00 mm (1.8-mm) using laser phaco energy coupled with high aspiration. But the problem of the incision still remained and the 1-mm barrier could not be broken. Today, the authors have started a new technique called PHAKONIT in which the size of the incision is below 1 mm. In other words the size of the incision through which the cataract is removed is 0.9 mm. The author (Amar Agarwal) performed this technique for the first time in the world on August 15th 1998. It was performed without any anesthesia. No anesthetic drops were instilled in the eye nor was any anesthetic given intracamerally. The first live surgery in the world of Phakonit was performed on August 22nd 1998 at Pune, India by the author (Amar Agarwal) at the Phako and Refractive Surgery conference. This was done in front of 350 ophthalmologists. This technique will revolutionize cataract surgery because now the foldable intraocular lenses which pass into the eye through an incision size of sub 2 mm (1.8 mm) will have to pass through a sub 1 mm incision.1 They will have to pass through a 0.9-mm incision.

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On April 10th 1999, a live surgical demonstration was done from Bangalore (India) which was telecast to the American Society of Cataract and Refractive Surgery (ASCRS) conference at Seattle (USA). In this 5 live surgeries were performed by the authors demonstrating Phakonit, Laser Phakonit and No Anesthesia Cataract Surgery. Principle The problem in phacoemulsification is that we are not able to go below an incision of 1.9 mm. The reason is because of the infusion sleeve. The infusion sleeve takes up a lot of space. The titanium tip of the phaco handpiece has a diameter of 0.9 mm. This is surrounded by the infusion sleeve which allows fluid to pass into the eye. It also cools the handpiece tip so that a corneal burn will not occur.2 The authors separated the phaco tip from the infusion sleeve. In other words, the infusion sleeve was taken out. The tip was passed inside the eye and as there was no infusion sleeve present, the size of the incision was 0.9 mm. In the left hand an irrigating chopper was held which had fluid passing inside the eye. The left hand was in the same position where the chopper is normally held, i.e. the side port incision. The assistant injects fluid (BSS) continuously at the site of the incision to cool the phaco tip. Thus the cataract is removed through a 0.9 mm opening. Phakonit to Correct Refractive Errors The same technique can be used to remove clear lenses when trying to correct refractive errors. If the patient is a high myopia, then instead of LASIK one can perform Phakonit. In these cases, one does not need an irrigating chopper also because the nucleus is very soft. In such cases an irrigating rod is used in the left (nondominant) hand. Once the soft nucleus is removed, bimanual cortical aspiration is done. An IOL is not implanted if the myopia is very high (depending upon the biometry). Thus the chances of creating astigmatism is very less. Terminology The name PHAKONIT has been given because it shows phaco (PHAKO) being done with a needle (N) opening via an incision (I) and with the phaco tip (T). Technique of Phakonit Anesthesia All the cases done by the authors have been done without any anesthesia. In these cases neither were anesthetic drops instilled in the eye nor was any intracameral anesthetic injected inside the eye. The authors have analyzed that there is no difference between topical anesthesia cataract surgery and no anesthesia cataract surgery. They have stopped using anesthetic drops totally in both their hospitals in India (Bangalore and Chennai).

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Incision In the first step a needle with viscoelastic is taken and pierced in the eye in the area where the side port has to be made. The viscoelastic is then injected inside the eye. This will distend the eye so that the clear-corneal incision can be made. Now a temporal clear-corneal incision is made. The problem here is that the diamond knives are all 2.6 mm or larger. Since our aim is to make only a 0.9-mm opening the diamond knives are not sufficient. So a microvitreoretinal (MVR) blade is used. This creates an opening of 0.9 mm. With time when companies start manufacturing diamond knives to create a 0.9-mm opening, one can start using them. When this incision is made it should be done in such a fashion that a clear-corneal valve is made. The authors have devised a keratome of 0.9 mm which they now use (Fig. 40.1). This keratome creates a good valve.

Fig. 40.1: Keratome to create a valve of 0.9 mm

Rhexis The rrhexis is then performed. This is done with a needle. In the left hand a straight rod is held to stabilize the eye. The advantage of this is that the movements of the eye can get controlled as one is working without any anesthesia. Hydrodissection Hydrodissection is performed and the fluid wave passing under the nucleus checked. Check for rotation of the nucleus. Phakonit The phaco tip without the infusion sleeve is kept in the right hand. In the left hand an irrigating chopper of 18 gauge is taken. The irrigating chopper is then

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passed through the side port into the eye. This is connected to the phaco machine. When the foot switch is in position 1 fluid passes into the eye and the eye gets distended. Now the phaco tip is passed into the eye. This is passed through the 0.9-mm incision. Remember the phaco needle has no infusion sleeve. The foot switch is pressed for phacoemulsification. Karate chopping is done with the left hand (Fig. 40.2) and the nucleus removed. The assistant injects fluid over the phaco tip at the area of the clear-corneal incision to prevent thermal burns of the eye.

Fig. 40.2: Phakonit being performed. Note the crack created by karate chopping. The assistant continuously irrigates the phaco probe area from outside to prevent corneal burns

CORTICAL WASHING, FOLDABLE IOL IMPLANTATION AND STROMAL HYDRATION Cortical washing is done with the bimanual irrigation-aspiration technique (Fig. 40.3). Note in Figure 40.3 the nucleus has been removed but there are no corneal burns. The irrigating probe is a blunt probe. This is like the irrigating chopper but does not have the chopper in it. The advantage of this is that as the chopper is not present the posterior capsule will not be cut accidentally. One can also use the bimanual irrigation/aspiration probes. If one wants they can also use the aspiration probe of the phaco machine but take out the sleeve of the probe. In cases of small pupil irrigation aspiration is difficult with this set-up so the authors devised an irrigating probe with a fork at the tip. The advantage of the fork is that it can push the iris with the left hand and the right hand with the aspirating probe can go under the rhexis and remove the trapped cortex. Figure 40.4 shows all three instruments, which can be, used in the left hand—the irrigating probe with a fork, the irrigating chopper and the blunt irrigating probe.

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Fig. 40.3: Bimanual irrigation aspiration. Note the clear corneal wound does not have any corneal burns

Fig. 40.4: Irrigating probe with a fork, irrigating chopper and irrigating probe. One can use either of these instruments in the left (nondominant hand)

Then the foldable IOL is implanted depending upon the biometry. If the case is of a cataract with high myopia and an IOL is not necessary then no lens is implanted. At present, the lowest available is the STAAR sub 2-mm foldable IOL’s so one has to increase the size of the incision from 0.9 mm to 2 mm. With time the foldable IOLs will come to less than 1 mm and the size of the incision will not have to be increased. The authors prefer the STAAR plate haptic foldable IOLs with large fenestrations. Finally the viscoelastic is removed with the bimanual

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irrigation aspiration technique and stromal hydration done. Injecting fluid into the sides of the clear corneal incisions induces stromal hydration. No subconjunctival injections or pad are applied in the eye. The patient walks out of the operation theater and is seen the next day. The next follow-up is after a month and suitable glasses prescribed if necessary. DISCUSSION This technique of Phakonit can change various concepts of cataract surgery. One of the main bugbears of cataract surgery was to break the 1-mm barrier. With Phakonit the barrier is broken. There are various questions, which come to one’s mind on this technique, and these will have to be answered with time as this procedure is so new. The first is of the left hand. The amount of fluid flowing into the eye normally in phaco is about 40 ml/minute. If we have a 20-gauge cannula in our left hand enough fluid does not flow inside the eye. So one has to use an 18-gauge irrigating chopper, otherwise when doing phacoemulsification the anterior chamber will collapse as the amount of fluid passing into the eye is very less compared to the suction. This problem can be solved with the use of an anterior chamber maintainer. The next problem is of the foldable IOL. At present the lowest one can go to 1.9 mm. Remember phaco came before the foldable IOL’s. So obviously once Phakonit catches on, the companies will have to manufacture foldable IOLs which pass through an incision of less than 1 mm. Another solution to solve the thermal burn could be to paint the tip of the phaco needle to insulate it from heating any structures. The solution of the problems of Phakonit could be the surgery of a three-port phakectomy in which an anterior chamber maintainer could be like the infusion cannula, an irrigating chopper could be the second port, and the phaco needle the third port just akin to a three-port vitrectomy. Another modification of Phakonit is the technique of Laser Phakonit. In this the laser probe is passed into the phaco probe so that one can use a two-port technique. LASER PHAKONIT Laser Phakonit uses laser energy (coupled with ultrasound energy in hard nuclei) to remove the nucleus. This technique was started first time in the world by the authors (Sunita Agarwal). The laser machine used is the Paradigm Laser Photon. In these cases, two ports are used. One port has fluid (BSS) flowing through an irrigating chopper of 20 gauge and in the other hand is the phaco probe without a sleeve. The laser probe is passed in the center of the phaco probe. The diameter of the phaco probe is 900 microns. The laser probe reduces the orifice opening to 550 microns. Thus the nucleus can be removed through a very small 0.9 mm opening.

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SUMMARY There are various problems, which are encountered, in any new technique and so also with Phakonit. With time these will have to be solved. The important point is that today we have broken the 1 mm barrier for cataract removals. This can be done easily by separating the phaco needle from the infusion sleeve. To reparaphrase the quotation from Robert Frost “We have miles to go before we can sleep”. R E F E R E N C ES 1. Sunita Agarwal, Athiya Agarwal, Mahipal S Sachdev, Keiki R Mehta, I Howard Fine, Amar Agarwal: Phacoemulsification, Laser Cataract Surgery and Foldable IOLs Jaypee Brothers: New Delhi, 1998. 2. Laura J Ronge: Clinical Update: Five Ways to avoid Phaco Burns February 1999.

Keiki R Mehta T P Lahane

Pharmacology of Intraocular Solutions and Drugs Used in Phacoemulsification

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INTRODUCTION Every cataract surgeon needs to use fairly large amount of pharmacological material at the time of surgery. If one needs to consider that each of the drugs must be perfectly balanced to be inimical to the eye, it is surprising the problems do not occur more often than they do. At virtually every stage of the cataract surgery extreme care has to be taken. The problems do not inadvertently arise due to an improper dosage or even a wrong application of an accepted drug. The potential for injury is much greater when solutions are used intraocular rather than applied from outside because the concentration to which the sensitive eye tissues are exposed is much higher. It is therefore important that extreme care has to be exercised in all stages. ANTISEPTIC SOLUTIONS Routine cleaning of the perioperative skin with antiseptic scrub solution in preparing the eye for cataract surgery is an effective technique. The concept is to reduce risk of bacterial contamination. This technique also helps in sterilizing the area immediately around the eye which is prone to be awash with irrigating solutions. Betadine 5% (povidone-iodine) has proven over time to be the most effective solution for this purpose. Hibiclens (chlorhexidine gluconate 4%) was popularly utilized in the early days. However a fair number of problems have resulted from its application which has led to its disuse. Phinney (1988) reported on five patients recently exposed to the solution who presented with symptoms of decreased vision and severe pain.

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Examination had revealed corneal epithelial defect with stromal edema and vascularization progressing over 2 to 10 weeks. Two patients had developed irreversible bullous keratopathy and required penetrating keratoplasty. In the remaining three patients the edema had cleared in six to seven months leading to a reduced endothelial cell density and mild stromal scarring. Hamed (1987) reported stromal thinning and ectasia with persistent epithelial defects in two cases. In both of them, dense irreversible corneal scarring resulted. On the other hand, Shore (1987) reported two cases which are limited purely to an epithelial involvement and recovered fairly rapidly. He felt that the benign course was due to a routine irrigation of the conjunctival sac with BSS prior commencing the surgery. Since most surgeons tend to wash out the conjunctival sac prior commencing surgery, the effect on the cornea and surrounding tissue is limited to the exposure time. It must be appreciated that whatever agent is used on the cornea, it should be free of surfactant, or detergent. Both the agents tend to lead to epithelial breakdown with perfusion in the eye leading to corneal stromal edema and endothelial cell damage. MacRae 1984 showed similar damage in rabbits with HibiClens, tincture of iodine, 3% hexachlorophene with detergent( pHisoHex) and 7.5% povidone-iodine with detergent (Betadine scrub). On the other hand, even 10% Betadine without detergent, led to no problems in the cornea. It would seem that corneal toxicity from antiseptic solutions is a potential problem but which can be diminished by not using detergents and preferably utilizing a non-toxic antiseptic like to 5% povidone-iodine. IRRIGATING SOLUTIONS Any intraocular surgical procedure requires copious irrigating solutions. It is the irrigating solution which while inflating the globe, maintains a proper pressure/ volume relationship during surgery, keeps the chamber properly deep and by aspiration of the same fluid, permits the debris to be flushed out. The potential for damage to the corneal endothelium is related to the chemical composition, its pH and osmolarity of the solution which bathes the tissues. Till the early sixties the common irrigating solution was normal saline. It took the work of Merrill, Fleming and Gerard in 1960 to show that its acidic pH of 6.8 and incomplete electrolyte balance was toxic to intraocular tissues. Balanced Salt Solution (BSS) subsequently developed by Merrill, has a stable but non-physiologic citrate acetate buffer, a pH of 7.5 to 8.2, and contains sodium, potassium, calcium, magnesium and chloride, a composition closely approximating aqueous humor. Till the 1970s the quantum which was required was so small that it used to be supplied in small squeeze bottles (15 ml). However with the advent of extracapsular cataract surgery, requirements of the solution went up (and so, unfortunately, did the cost) with the result that surgeon’s began looking out for alternate cheaper solutions. Dikstein and Morris in 1972 used modified bicarbonate Ringer’s solution containing glutathione, adenosine and glucose, and showed conclusively that it would preserve

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the corneal endothelium function. However commercial formulation of a glutathione bicarbonate Ringer (GBR for short ) solution was difficult because of the inherent instability of reduced glutathione, adenosine and bicarbonate. Alcon laboratories made BSS Plus to be as similar to GBR and be effective while maintaining pharmacologic sterility, stability and shelf-life. BSS Plus is a two-component bicarbonate buffered, electrolyte solution containing oxidized glutathione and glucose but no adenosine. Once reconstituted the solution will maintain a physiological pH for up to 24 hours. Laboratory Studies Edelhauser et al (I978) had shown on laboratory studies of isolated perfused human cornea’s that BSS Plus maintains virtually normal cornea thickness. BSS Plus causes human perfused cornea stored at 4°C to deturgesce as the temperatures is increased to 37 degree centigrade. The endothelial metabolic pumps become functional and the endothelial ultrastructure is maintained, with the use of BSS Plus while the use of lactated Ringer, plain BSS and Hartmann’s lactated Ringer did not do so. Surprisingly enough, the use of BSS or Ringer’s, leads to corneal swelling which is seen to compromise endothelial barrier function. Increased permeability is consistent with the disruption of intraendothelial cellular junctions observed in scanning and transmission electron micrographs of corneal endothelium after perfusion both with Ringer is as well as with BSS (Nuyts and Edelhauser, 1995). Another interesting finding was by Glasser (1985,1988) that, in vivo anterior chamber perfusion in monkeys have shown that both BSS plain, Hartmann’s SMA-2 and Ringer lactate can irreversibly stress the endothelium inducing corneal swelling after one hour and significant abnormal endothelial cell morphology after, as little as 15 minutes of irrigation. BSS Plus prevented changes in endothelial cell morphology and corneal swelling after irrigation lasting almost two hours. In a more recent study by Nuyts (1995) to evaluate HLR (Hartmann’s lactated Ringer solution) the use of HLR showed that it caused corneal swelling, endothelial cell ultra structure changes (endothelial cell edema and cytoplasmic vacuolization). Interestingly enough, Nuyts (1995) also commented that the use of BSS Plus can reverse the corneal swelling induced by HLR. In the clinical studies comparing BSS to BSS Plus, Kline at el in 1983 found significantly less endothelial cell loss will BSS Plus (15.4%) than with BSS (22.7%) in other patients after ECCE and was the resemblance implant performed without a visco-elastic. Benson 1981 in a well-designed prospective study found significantly less corneal edema on the first day after Whitaker with BSS Plus than with lactated ringer. There is a paucity of studies comparing BSS with BSS Plus. Kline (1982) showed that there was significantly less loss of endothelial cells using BSS Plus (15.4%)as compared to BSS (22.7%). Despite many studies which show that the endothelial cell count is different, one has to clearly appreciate that simple endothelial cell loss does not demonstrate the subtle changes associated within the irrigating solution which can be depicted in the early postoperative period. We know that endothelial

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cell loss continues throughout life and the cornea remains clear by virtue of the endothelial cell reserve which with its vital function maintains deturgescence. Any surgical or non-surgical insult tends to shift the endothelial cell loss curve towards progressive decompensation (Mishima, 1982). Thus even a slight increase in the rate of endothelial cell loss can significantly reduce the clarity about lifespan of the corneal endothelium. Patients with low endothelial cell densities of the endothelium (diabetics) are known to be more susceptible to surgical stress. Even stresses such as contact lens wear, persistent iritis or glaucoma can lead to corneal decompensation. In cases where the endothelial cells has already compromised it would therefore make sense that the most physiological, non-traumatic, endothelial cell viable, irrigating solution should be utilized to give the endothelial cells the maximum chances to survive. The question often asked is why does BSS Plus maintain better structure and functional integrity of intraocular tissues as compared to ordinary BSS or Ringer lactate. This question had been answered by Winkler (1977) who felt that the difference was essentially in the buffer. Bicarbonate in BSS Plus is the major buffer present in aqueous and effective in the physiological pH range of 6.00 to 8.00. Bicarbonate is also important for normal retinal function (Moorhead, 1979). The citrate-acetate in BSS is effective only at non-physiologic pH levels of 3.6 to 6.2. Citrate may also chelate calcium which would disrupt endothelial cell functions and barrier function (Stern, 1981). On the other hand, Ringer lactate lacks a buffer alltogether. Other chemical differences between the solutions to play an important role. Glutathione is needed for maintenance of endothelial cell junctions and barrier function and also plays an essential role in endothelial fluid transport (Whikehart DR, 1978). Glucose is an essential energy source for maintenance of aerobic metabolism. It is also used for ATP production for the Na/K pump and NADPH production to reduce glutathione and prevent oxidative damage to endothelial cells. Another factor which is offen not taken into account is the time the solution stays in contact with the endothelium. Often one seems to consider the contact time is only the surgery time, thinking erroneously, that aqueous replenishes itself virtually immediately. McDermott and Edelhauser in 1988 calculated that it takes over four hours for the aqueous to replace the fluid left in the antierior chamber at the end of surgery. However an important consideration also is that the aqueous fluid production is nearly always reduced by surgery with a 50% reduction being otter, thus creating solution would remain in the postoperative eye for almost 8 hours. Another important consideration when the solution is utilized with phacoemulsification is the temperature of the solution. Although 37 degree centigrade is considered physiological it would seem more likely that the temperature would be much higher than that especially since the irrigating solution is also utilized to cool the phacoemulsification tip. Accelerated metabolic activity with increased glucose/oxygen consumption and even denaturation of some proteins may occur if the temperature rises just a few degrees about 37 degrees centigrade (Edelhauser, 1987). It is for this reason that the use of cooling solutions has been recommended, by running the tube through an icy bath. Reduced temperatures would reduce the rate of

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biochemical reactions and reduce inflammation and in addition reduce the risk of a scleral burn from the hot phaco needle, especially when hard cataracts are being tackled by phacoemulsification. Contamination of Irrigating Solution Poor packaging and poor manufacture have led to the bane of contaminated irrigating solution inducing multiple epidemics all over the world. In 1980 Pettit reported 13 cases of fungal endophthalmitis following cataract surgery. The responsible organism being Paecilomyces lilacinus which was traced to a contaminated lot of sodium bicarbonate used to neutralize IOL sterilizing solutions. Fortunately these methods are no longer used. The filamentous fungus a Cladosporium, and Ulocladium were isolated in 1984 from separate lots of 15 ml BSS in plastic squeeze bottles (O’Day and Summers 1987). The largest epidemics was caused by Candida parapsilosis reported by the Stern and Googe (1984 and 1985). Regrettably the time of onset of symptoms to initiation of antifungal treatment ranged from one week to over four weeks, and the final visual outcome was counting fingers or less in one-quarter of the patients. India regrettably has had a spate of infections all over. There have been a number of reasons why in camps literally hundreds of eyes have been lost due to improper packaging and transport of solutions.There have been innumerable cases reported in India where the improper irrigating substances have led to corneal decompensation problems. Perhaps the most notorious was reported in 1995 with aqueous solution termed as Irrigasol, where 106 corneas were lost due to an admixture, of chlorhexidine into the irrigating solution. The quantity was such that in 24 hours the corneas became opaque. Regrettably the laboratories in India could not isolate the contaminant. It required with good offices of Professor John J Alpar in USA to evaluate the solutions and with rabbit experiments to isolate the contaminant which precipitated the problem. Subsequently this solution was taken off the market. The standards applied for the manufacture of irrigating solution are inadequate to maintain sterility with over political support which has led to a large number of lost eyes. Of the various solutions BSS has been perhaps, surprisingly, the worst offenders. The reason is not far to see. The lot is made in a single batch and subsequently not repeated for many months as the offtake of the solutions is very low due to its high cost. Since BSS has no preservative innate over a period of time problems tend to end seem again due to the improper packaging. Till the present moment excepting for one imported BSS solution (Alcon), no other manufacture has made its high quality BSS available. Regrettably the cost of the solution exceeds the cost of 10 cataract surgeries put together and therefore is very rarely utilized. Reuse Irrigating solutions are essentially single use solutions and hence should never be reused. As far as possible unit containers should be utilized so that in cases the solution is contaminated the infection would not spread to another case.

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VISCOELASTIC SUBSTANCES Viscoelastic substances are used to protect the corneal endothelium during cataract surgery and at the same time permit more space in the anterior chamber. They are also utilized to move tissues which a delicate, to separate layers, an all in all literally work like a third instrument in the eyes. They are also used to facilitate intraocular insertion of lenses either directly or via an injector. The commonly used solutions are sodium hyaluronate (Healon Amvisc), chondroitin sulfate/’sodium hyaluronate (Viscoat)’, hydroxypropylmethylcellulose (HPMC) (OcuCoat, Visilon, Hyprosol, Moisol). All these viscoelastic substances though effective in an identical manner vary significantly with respect to their tendency to remain in the anterior chamber during surgery. Healon has the highest viscosity and therefore has the best ability to maintain space and thereby manipulate tissue. However it is not very effective in phacoemulsification, as it tends to come out very easily. This problem with Healon has now been dispelled with the new Healon 5, which has the ability to remain in the chamber for a prolonged period of time. Viscoat (Alcon) and HPMC remain in the anterior chamber in large quantities during phacoemulsification and during mediation, and thereby protect the endothelium during the procedure. In an effort to protect the endothelium more and more stress is placed on viscoelastic which would stay in the chamber for a prolonged period of time, however this very advantage may prove to be a problem as retained viscoelastic traps air-bubbles, lenses fragments, has the potential for reduced visibility, and require more thorough aspiration for removal. If the viscoelastic is not perfectly balanced and manufactured this very protection may enhance the risk of later corneal decompensation. Viscoelastic substances are difficult to make, as they need to be filtered using a compressed filtration technique. In an effort to side step this important procedure, many laboratories have put out solutions and the Indian market which have proven deleterious to the eye. Numerous smaller outbreaks have resulted from improper viscoelastic solution, literally too many to even recount. Thus it becomes imperative that no matter who makes the viscoelastic and as to how well it is preserved, it is advisable to individually check each syringe or lot under the operating microscope prior usage to assure clarity and container integrity. In addition, during surgery, an effort should be made towards removal of every single bit of the solution prior closing the eye. It would perhaps be wise to autoclave all solutions prior usage. ANTIBIOTICS Prophylactic antibiotic usage and cataract surgery are based on the fact that the risks of endophthalmitis and its complications are far greater than the risk of inducing an endothelial toxicity. The source of infection can be from anywhere, contamination of solutions, instruments, immediate environment, cross-contamination of the surgeon’s hands, and even infection from periocular structures. In the United States, the incidence of endophthalmitis after cataract surgery has been reported to be between 0.71% and 3.05%. However the incidence of postoperative endophthalmitis

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diminished to 0.056 to 0.11% when the operating antibiotics were employed: (Starr 1983, Kattan 1991). Timing and the route of administration are the two most important considerations in the use of prophylactic antibiotics. Topical antibiotics must be administered for at least 24 hours prior surgery to effectively decrease bacterial counts in the conjunctival sac. On the other hand, topical therapy for more than one week or ten days postoperatively, is neither effective nor necessary since the wound is sealed with an epithelial plug by three to five days. Prolonged topical therapy of antibiotic invariably contributes to epithelial toxicity and promotes the development of resistant strains. The use of subconjunctival injections following surgery was extremely useful, as it permitted high levels of antibiotics to the site of potential infection. However with the advent of topical anesthesia, the use of subconjunctival injections as a means of antibiotic delivery has now fallen into disrepute. A number of authors, Howard Fine, Gimbel et al have shown that the incidence of endophthalmitis has significantly decreased with the usage of antibiotics added to the irrigating solution. Gritz 1996, on the contrary has shown that the exposure to antibiotics for a short period of time during the intraocular surgery has no effect on the organisms commonly responsible for endophthalmitis. However the usage of vancomycin in the intraocular drip seems to have diminished significantly endophthalmitis especially propionibacteria. It must however be clearly noted that there is no way in which the surgical field can ever be made totally sterile and despite the usage of antibiotics, topical, in the irrigating solution, or even intraocularly, the best prevention is an exacting technique with exceptional, sterile precautions. ANTIINFLAMMATORY AGENTS Topical antiinflammatory agents are typically used to control postoperative inflammation. Corticosteroids are the mainstay of therapy. Prednisolone phosphate or acetate 1%, dexamethasone sodium phosphate 0.1% or fluorometholone 0.05% drops are commonly administered three to four times a day subsequently tapering with diminishing degree of inflammation. These drugs have the potential for increasing IOP although they do reduce significantly the inflammatory response, on the other hand, they also reduce the wound healing and diminish local immune competence.Topical NSAIDs have been shown to reduce inflammation after cataract surgery however they do not seem to have the same capabilities. They could be used in combination with steroid, though at present there is no properly controlled studies to either discard to or obviate that concept. There has been reports to commence diclofenac eye drops three days prior cataract surgery in an effort to reduce the risk of cystoid macular edema. ALTERNATE ADDITIVES Various agents or drugs like glucose, Heparin, tissue plasminogen activator, thrombin, glucose may have a role with the concept that it would improve postoperative

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inflammation and diminish possibilities of iritis. However it must be clearly appreciated that the use of an additive alters the formulation stability pH of the irrigating solution and even its osmolarity with results which can often be problematic. It must be clearly appreciated that additives should only be used for specific indications and never routinely. The only approval application of additives would be the use of glucose in diabetic patients (Haimann 1982, 1984) where it can prevent intraoperative posterior supcapsular opacification during vitrectomy. The glucose is taken as 3.00 ml of 50% dextrose (in sterile water with no preservatives) and added to a 500 ml bottle of BSS Plus. This increases the osmolarity to 330 mOsm, which restores the equilibrium. The rationale would seem to be that diabetics have polyols trapped within the lens, which causes the lens itself to become hyperosmotic and thus opacify (KInoshta, 1986). MYDRIATICS AND MIOTICS Pupil dilatation is extremely important in phacoemulsification. Customarily pupil is dilated with easier combination of topical anticholinergic agents (tropicacyl 1%, cyclopentolate 1%, homatropine 2%,), and sympathetic agonists (phenylephrine 2.5% to 10% solution). The dark brown iris requires much more dilating solution than the light gray or blue iris as is customarily seen in Europe, Scandinavia or America. Not only they need to be out more frequently but also for longer duration to achieve the same level of mydriasis. Caution has to be taken with topical phenylephrine of higher in patients with hypertension. Occluding the punctum with a cotton swab prior to instilling the drops will prevent the rise. Care must also be taken not to dilate the pupils a day prior surgery as this exhausts them and they will not dilate to the same degree at the time of surgery. Many authors have reported that adding topical NSAIDs such as indomethacin 1%, flurbiprofen 0.03% , diclofenac 1% help to maintain mydriasis during cataract surgery. Presumably this is a result of prostaglandin synthesis inhibition. However Well (1989) notes that intraocular epinephrine is a much more potent mydriatic than any NSAID, and Bito (in 1990) points out that no known prostaglandin is sufficiently effective in humans to account for surgical miosis. Utilising repeated application of topical epinephrine may result corneal epithelial sloughing, drug-induced stromal edema, and endothelial toxicity of preparations containing a non-physiological Barford weaker and what is much worse benzalkonium chloride. The use of epinephrine has an additive effect to irrigating solution and has been the choice of most ophthalmologists over the years. Reports of corneal edema after its use in 1982 let studies of the effective commercially available epinephrine preparations on the corneal endothelial develop further (Dohlman 1972, Edelhauser 1982). The toxicity was due to the presence of sodium bisulfite, a preservative/ antioxidant. However the usage of half ml on one and thousand of epinephrine added to 500 ml of BSS Plus apparently gives no problems.

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FURTHER READING 1. Phinney RB, Mondino BJ, Hofbauer JD et al: Corneal edema related to accidental Hibiclens exposure. Am J Ophthalmol 106: 210-15, 1988. 2. Hamed LM, Ellis FD, Boudreault G et al: Hibiclens keratitis. Am J Ophthalmol 104: 50-56, 1987. 3. MacRae SM, Brown B, Edelhauser HF: The corneal toxicity of presurgical skin antiseptics. Am J Ophthalmol. 97: 221-32, 1984. 4. Merrill DL, Fleming TC, Girard LJ: The effects of physiologic balanced salt solutions and normal saline on intraocular and extraocular tissues. Am J Ophthalmol 49: 895-98, 1960. 5. Dikstein S, Maurice DM: The metabolic basis to the fluid pump in the cornea. J Physiol 221: 29-41, 1972. 6. Edelhauser HF, Gonnering R, Van Horn DL: Intraocular irrigating solutions—a comparative study of BSS Plus and lactated Ringer’s solutions. Arch Ophthalmol 96: 516-20, 1978. 7. Edelhauser HF, Van Horn DL, Schultz RO et al: Comparative toxicity of intraocular irrigating solutions on the corneal endothelium. Am J Ophthalmol 81: 473-81, 1976. 8. Edelhauser HF, Van Horn DL, Hynduiuk RA et al: Intraocular irrigating solutions—their effect on the corneal endothelium. Arch Ophthalmol 93: 648-57, 1975. 9. Edelhauser HF, Rosenfeld SI, Waltman SR et al: Discussion of comparison of intraocular irrigating solutions in pars plana vitrectomy. Ophthalmology 93: 114-15, 1986. 10 Edelhauser HF: Intraocular irrigating solutions. In: Lamberts DW, Potter DE (Eds): Clinical Ophthalmic Pharmacology. Little Brown and Co: Boston, 431-44, 1987. 11. Nuyts RMMA, Edelhauser HF, Holley GP: Intraocular irrigating olutions—a comparison of Hartmann’s lactated Ringer’s solution, BSS and BSS Plus. Graefes Arch Clin Exp Ophthalmol 233:655-11, 1995. 12. Kline OR (Jr), Symes DJ, Lorenzetti, OJ et al: Effect of BSS plus on the corneal endothelium with intraocular lens implantation. J Toxicol. Cut & Ocular Toxicol 2(4-5): 243-247, 1983. 13. Mishima S: Clinical investigations on the corneal endothelium, XXXVIII Edward Jackson Memorial Lecture. Am J Ophthalmol 93: 1-29, 1982. 14. Winkler BS, Simson V, Benner J: Importance of bicarbonate in retinal function. Invest Ophthalmol Vis Sci 167: 766-68, 1977. 15. Moorhead LC, Redburn DA, Merritt J et al: The effects of intravitreal irrigation during vitrectomy on the electroretinogram. Am J Ophthalmol 88: 239-45, 1979. 16. McDermott ML, Edelhauser HF, Hack HM et al: Ophthalmic irrigants—a current review and update. Ophthalmic Surg 19: 724-33, 1988. 17. Pettit TH, Olson RJ, Foos RY et al: Fungal endophthalmitis following intraocular implantation—a surgical epidemic. Arch Ophthalmol 98: 1025-39, 1980. 18. O’Day DM, Sommer A: Clinical Alert 1/1. American Academy of Ophthalmology, October 18, 1984. 19. Stern ME, Edelhauser HF, Pederson HJ et al: Effects of ionophores X537A and A23187 and calciumfree medium on corneal endothelial morphology. Invest Ophthalmol Vis Sci 20: 497-507, 1981. 20. Stern WH, Tamura E, Jacobs RA et al: Epidemic postsurgical Candida parapsilosis endophthalmitis— clinical findings and management of 15 consecutive cases. Ophthalmiology 92: 1701-09, 1985. 21. Kattan HM, Flynn HW, Pflugfelder SC et al: Nosocomial endophthalmitis survey—current incidence of infection after intraocular surgery. Ophthalmology 98: 227-38, 1991. 22. Starr MB: Prophylactic antibiotics for ophthalmic surgery. Suru Ophthalmol 27: 353-73, 1983. 23. Gimbel HV: Nucleofractis through a small pupil. Can J Ophthal 27: 115-19, 1992. 24. Gimbel H, Neuhann T: Development, advantages, and methods of the continuous circular capsulorrhexis technique. J Cataract Refract Surg 16: 31-37, 1990. 25. Mehta KR: When not to do an anterior chamber implant. All India Ophthl Soc Proc 164-65,1986. 26. Mehta KR, Sathe SM, Karyekar SD: Intraocular lens manufacturing quality assessment, Xth Congress APAO Soc Proc 1:419-20,1985. 27. Mehta KR, Sathe SM, Karyekar SD: New soft posterior chamber implant. Xth Congress APAO Soc Proc 1:421-23, 1985. 28. Mehta KR: The new colver leaf stabiliser (CLS) for the safe and effective insertion of posterior chamber IOL over a broken capsular face. All India Ophthl Soc Proc 251-53,1995. 29. Mehta KR: Hema intracameral Hood—corneal turbulence control in phaco. All India Ophthl Soc Proc (Chandigarh) 1996. 30. Mehta KR: Methylcellulose induced sterile endophthalmitis following phacoemulsification. Proc of SAARC Conference, Nepal, 1994. 31. Mehta KR: Effective endothelial cell protection during phacoemulsification with Hema intracameral contact lens (HICL). Proc of SAARC Conference, Nepal, 1994.

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Emilio Balestrazzi Leopoldo Spadea Luigi Mosca

Triple Procedure with Phacoemulsification before Trephination

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INTRODUCTION The triple procedure consists in the combined surgery of penetrating keratoplasty (PK) associated with the cataract extraction and the implantation of intraocular lens (IOL). In 1966, Katzin and Meltzer have reported combined cataract extraction and penetrating keratoplasty.1 Then, in 1976, IOL implantation was added to this technique,2 using first iris-fixated lenses and then posterior chamber lenses,3 improving the results of the triple procedure. Compared with the two-step surgery, the triple procedure allows faster visual rehabilitation without compromising graft survival, lowering cost of surgery.4 Indications for the triple procedure are all those cases in which coexist a corneal pathology and an opacity of the lens. This association of pathologies is referred in Literature in the case of Fuchs’ corneal dystrophy (from 30 to 45.5%),4-7 infectious keratitis (from 20 to 26%),5, 7 corneal scaring (10%),6 ReisBuckler dystrophy,7 graft failure,8 keratoconus (3%),6, 9 and in the case of systemic disease as in Down’s syndrome.10 In the triple procedure, the cataract extraction phase could be performed as extracapsular (ECCE)7, 9, 11 or phacoemulsification (PHACO).2, 12-14 On the contrary, the corneal and the cataract surgery could be performed in two different steps, first the PK and, in a second time, ECCE + IOL or PHACO + IOL.4, 10 The triple procedure presents a lot of advantages: first of all in a single surgery time both the pathologies can be resolved, reaching a more rapid functional recovery with less trauma on the transplanted graft and less endothelial cells loss.7 Moreover a lot of patients submitted to PK after some years show an evolution of the cataract.15 In 1994 Dangel compared 51 eyes submitted to triple procedure (PK + ECCE +

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IOL) and 279 eyes submitted to simple cataract extraction and insertion of IOL in posterior chamber (ECCE or PHACO + IOL in PC) and showed that the incidence of posterior capsular opacity (PCO) was, respectively, of 9.8% and 36.2%. Therefore this less incidence of PCO shows that the triple procedure is to be preferred.15 The triple procedure PK + PHACO + IOL offers some advantages: possibility to work with a closed globe during all the cataract and IOL phases (phacoemulsification, aspiration of cortex, IOL implantation) and the following PK can be performed with a small pupil.2, 12-14 On the contrary PK + ECCE + IOL open sky procedure is faster and with an optimal visibility of the surgery field.9 Both the techniques, however, show some disadvantages. With the open sky ECCE an increased risk of choroidal effusion after corneal trephination is present, with high risk of vitreal loss in case of discontinuity of the capsulorrhexsis, that has to be very large.12 Other complications with this technique are the incomplete aspiration of cortex, anomalous positioning of the IOL, choroidal hemorrhage13 and a higher postoperative astigmatism, with a slower functional recovery time. The disadvantages of the PK + PHACO + IOL technique are limited to the length of the procedure and to the difficulty of technical execution, especially in the presence of corneal opacities that limit the view of the surgical field. In case of two different surgical procedures: [(i) PK, and (ii) ECCE + IOL or PHACO + IOL] there are a lot of advantages. The postoperative refractive error is lower comparing to the triple procedure; in fact it is possible to perform a more precise axial length measurement with an exact IOL power calculation, because the evaluation is carried out not on presumed parameters but on real ones.16, 17 The postoperative astigmatism results are also better. In fact, the tunnel of the PHACO can be performed on the steepest corneal meridian to flatten it. In addition a corneal refractive surgery can be performed to correct residual astigmatism after PK.18 Another advantage is that both procedures can be performed in local anesthesia, with better compliance for the patient. However, some disadvantages are present too. The patient is submitted to a greater surgical stress, with a higher risk of damaging the graft. Our Personal Technique of Triple Procedure We prefer the technique of phacoemulsification with implantation of IOL in CP before trephination, performed in general anesthesia. To calculate the IOL power to be inserted a keratometric value of 43D was considered. Surgical Technique Marking the center of the host cornea with a surgical pen. Performing of a clear cornea tunnel with a crescent blade knife and opening of the anterior chamber (AC) with 3.2 mm calibrated knife. Introduction of viscoelastic substance in AC and performing a circular continuous capsulorrhexsis (Fig. 42.1). Hydrodissection, hydrodelineation and phacoemulsification of the cataractous nucleus with a divide and conquer or a stop and chop technique (Fig. 42.2). Cortex aspiration with a two-way I/A system. Introduction of viscoelastic substance and IOL implantation

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Fig. 42.1: Circular continuous capsulorrhexis

Fig. 42.3: IOL implantation in the capsular bag

Fig. 42.2: Phacoemulsification

Fig. 42.4: Suction and trephination of the host cornea

in the capsular bag (Fig. 42.3). Introduction of acetylcholine in AC to get a miotic pupil. Suture of the corneal tunnel with a single 10/0 nylon stitch. The system for cutting donor buttons was that the Hanna Suction Punch Block (Moria-Dugast, Paris, France)19 that consists of a concave Teflon well in which the donor corneo scleral shell is secured by gentle suction. A cylindrical guide ensures that the disposable razor blade trephine is centered and is perpendicular during punching from the endothelium side. Donor corneas were preserved in Optisol medium (Chiron Oph.,

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Figs 42.5 and 6: Completion of the incision with surgical knife and scissors

Fig. 42.7: Cardinal sutures (6-, 12-, 9- and 3- O’ clock position)

Fig. 42.8

Irvine - Ca, USA). Alignment of the Hanna trephine over the cornea (Fig. 42.4), suction and trephination of the host cornea till aqueous loss and completion of the incision with surgical knife and scissors (Figs 42.5 and 6). The corneal button diameter was 0.25 mm bigger than the recipient bed. In all patients the corneal button was secured in the recipient bed with four 8/0 silk cardinal sutures (6-, 12-, 9- and 3-O’clock position) (Fig. 42.7). Performing of a double running antitorque 12 + 12 bites 10/0 nylon suture. The four cardinal sutures were removed

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Figs 42.8 and 9: Double running antitorque 12 +12 bites 10/0 nylon suture

Fig. 42.11: Clinical image of a transplanted eye with a mixed (single running 12 bites + 8 single stitch) 10-0 nylon suture, with a 1 O’clock corneal phaco tunnel sutured with a single 10-0 nylon stitch

Fig. 42.10: Clinical image of a transplanted eye with a double running anti-torque 12 + 12 bites 100 nylon suture, with a 12 O’clock corneal phaco tunnel sutured with a single 10/0 nylon stitch

Fig. 42.12: Particular of a one-stitch clear corneal phaco tunnel

before the two running sutures were tightened (Figs 42.8 and 9). Evaluation of corneal sphericity was made using the handle Karickhoff keratoscope (Surgidev Corp, Goleta —Ca, USA). The cones were cauterized before trephination. Postoperative Therapy All patients received gentamicin sulfate 20 mg IM, methylprednisolone 30 mg IM and ofloxacin 0.3% drops at the end of surgery. All the eyes were patched until corneal epithelial defects were healed, and then steroid drops (fluorometholone 0.1%) were given every 6 hours, and gradually tapered, usually for less than 6 months.

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Fig. 42.13: Postoperative clinical image of an eye, submitted to triple procedure, after suture removal

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In 1998 we presented a study evaluating the effectiveness of our surgical technique (Indian Academy of Ophthalmology International Congress (Eye advance 1998) in Mumbai, 17-20 September 1998). We prospectively studied a group of 16 eyes of 16 patients who underwent triple procedure with phacoemulsification before trephination, between September 1996 and July 1997. Patients who had shown any sign of rejection were excluded from the study. Seven eyes were affected by keratoconus, two by endothelial dystrophy, and seven

Fig. 42.14: Computerized corneal topography after 2 months from the triple procedure (normalized scale, left tangential map, right axial map)

by central corneal scar. The data were compared with a group of patients submitted to triple procedure of PK + ECCE + IOL (Fig. 42.13) and with a group of PK alone. Visual acuity measurements and refractions were performed by masked residents at approximately 1, 3, 6, 9, 12, 18, and 22 months postoperatively. Corneal topography was analyzed (Figs 42.14 to 16) by a single observer in each examination using a computerized videokeratoscopy (Corneal Analysis System, EyeSys Laboratories, Houston-Texas, USA). Four keratoscopic images were obtained from each eye, and the best image was chosen. The data listed as the keratometric difference at 3 mm was considered the computerized topographic astigmatism. The final measurements of all data were done after that the sutures were removed. Statistical analysis was performed using the Student’s t-test. Follow-up ranged between 12 and 22 months (mean 17.5 +/- 4.73 SD). The mean preoperative visual acuity was 20/200 +/- 0.06 SD, while the mean postoperative visual acuity was 20/32 +/- 0.12 SD (range from 20/50 to 20/25). The preoperative refractive error in spherical equivalent (SE) ranged from -26D to +1D (mean -8.25D +/- 10.94 SD) and the refractive outcome was

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Fig. 42.15: Computerized corneal topography after 5 months from the triple procedure (normalized scale, left tangential map, right axial map)

Fig. 42.16: Computerized corneal topography after suture removal (normalized scale, left tangential map, right axial map)

emmetropia (+/- 1.50D) for 80% of patients and myopia for the rest. The final refractive cylinder measurements ranged from +1.75D to -2D (mean +0.10D +/- 1.74 SD). The final computerized topographic keratometric measurements ranged from 36.48D to 44.06D (mean 40.24D +/- 2.31 SD). Mean postoperative computerized topography astigmatism was 2.96D +/- 1.39 SD. These data were not statistically significantly different with respect to the PK group (3.6D +/- 1.7 SD; p = 0.233), but were statistically

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Fig. 42.17: Graphic comparing the astigmatic outcomes of triple procedure, simple keratoplasty and two-step procedure

different with respect to the PK + ECCE + IOL group (4.9D +/- 2.3 SD; p = 0.004). Regarding the better corneal astigmatism in PHACO group versus ECCE group (2.96D +/- 1.39 SD Vs 4.90D +/- 2.30 SD) (Fig. 42.17), one could consider that after the open sky cataract extraction the globe gets partly deformed due to mechanical solicitations, with greater difficulty for the surgeon during the suture phase. No capsular dehiscence or vitreous loss was noted during operation. No patient had postoperative glaucoma and no wound dehiscence was noted during the followup. In conclusion, we think that the surgical technique must be always personalized to the operator, who, on the basis of his or her own experiences, will choose the best solution for each single case. REFERENCES 1. Katzin HM, Meltzer JF: Combined surgery for corneal transplantation and cataract extraction. Am J Ophthalmol 62: 560, 1966. 2. Groden LR: Continuous tear capsulotomy and phacoemulsification cataract extraction combined with penetrating keratoplasty. Refract Corneal Surg 6(6): 458-59, 1990. 3. Brady SE, Rapuano CJ, Arentsen JJ et al: Clinical indication for and procedures associated with penetrating keratoplasty, 1983-1988. Am J Ophthalmol 108: 118-22, 1989. 4. Pineros OE, Cohen EJ, Rapuano CJ et al: Triple vs nonsimultaneous procedures in Fuchs’ dystrophy and cataract. Arch Ophthalmol 14(5): 525-28, 1996. 5. Borderie V, Touzeau O, Laroche L: Value of implantation in the capsular bag during combined operation of penetrating keratoplasty and cataract surgery. J Fr Ophtalmol 20 (3): 200-06, 1997. 6. Djalilian AR, Geoge JE, Doughman DJ et al: Comparison between the refractive results of combined penetrating keratoplasty/transsclerally sutured posterior chamber lens implantation and the triple procedure. Cornea 16 (3): 319-21, 1997.

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7. Geerards Aj, Hassmann E, Beekuis WH et al: Triple procedure; analysis of outcome, refraction, and intraocular lens power calculation. Br J Ophthalmol 81 (9): 774-77, 1997. 8. Erb C, Zimermann-Burg B, Steuhl KP et al: Retrospective long-term follow-up of the triple procedure (combined keratoplasty and cataract surgery). Folia Med (Plovdiv) 38 (2): 19-25, 1996. 9. Sanford DK, Klesges LM, Wood TO: Simultaneous penetrating keratoplasty, extracapsular cataract extraction and intraocular lens implantation. J Cataract Refract Surg 7 (6):824-29, 1991. 10. Goto S, Minoda S, Suzuki S: Penetrating keratoplasty for keratoconus in a case of Down’s Syndrome. Nippon Ganka Gakkai Zasshi (2): 173-77, 1995. 11. Baca LS, Epstein RJ: Closed-chamber capsulorrhexis for cataract combined with penetrating keratoplasty. J Cataract Refract Surg 24 (5): 581-84, 1998. 12. Menapace R: M-procedure: modified corneal triple procedure using a temporary keratoprosthesis for small-incision cataract surgery in a close system. Eur J Implant Refract Surg 3(3): 207-13, 1991. 13. Malbran ES, Malbran E, Buonsanti J et al: Closed-system phacoemulsification and posterior chamber implant combined with penetrating keratoplasty. Ophthalmic Surg 24(6): 403-06, 1993. 14. Lindquist TD: Open-sky phacoemulsification during corneal transplantation. Ophthalmic Surg 25(10): 734-36, 1994. 15. Dangel ME, Kirkham SM, Phipps MJ: Posterior capsule opacification in extracapsular cataract extraction and triple procedure—a comparative study. Ophthalmic Surg 25(2): 82-7, 1994. 16. Binder PS: The triple procedure—refractive results. 1985 update. Ophthalmology 93(12): 1482-88, 1986. 17. Musch DC, Meyer RF: Prospective evaluation of a regression-determined formula for use in triple procedure surgery. Ophthalmology 95 (1): 79-85, 1988. 18. Troutman RC, Gaster RN: Relaxing incision for control of postoperative astigmatism following keratoplasty. Ophthalmic Surg 11: 117-20, 1980. 19. Spadea L, Bianco G, Mastrofini MC et al: PK with donor and recipient corneas of the same diameter. Ophthalmic Surg 27 (6): 425-30, 1996.

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Keiki R Mehta

Multiport Phaco Tip: A Safer and More Effective Training Device for Phacoemulsification

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INTRODUCTION Phacoemulsification is a superb technique and is now a well-recognized procedure. However like all good surgical techniques, despite theoretical teaching and subsequently practical instruction on animal eyes, the finer points can only be taught, hands-on, on patients. Phacoemulsification has also its complications if inappropriately done; the problem has always been how to teach phacoemulsification without leaving complications. Even in the best hospitals in the world, the teaching curve of residents will always leave behind a trail of broken capsules and even an occasional dropped nucleus. A decade ago, when phacoemulsification, was still rising out of the dark ages, at most major meetings, worldwide, the teaching curve of this procedure was always alluded to as overly extended. A popular saying was “ The road to phacoemulsification is slippery with vitreous” and “Dropped nuclei are the milestones in the path of phacoemulsification”. Fortunately, these days have long gone. Still complications do occur. Any new technique that could reduce this problem is always useful. To obviate the major risk in phacoemulsification, namely the broken capsule and its following train of complications, a multiport phaco tip has been designed which would seem to work very well. However to really appreciate how this tip works one needs to know a little more about the functions and the drawbacks of the phaco tip.

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THE FUNCTIONS OF A PHACO TIP The phacoemulsification handpiece generates ultrasound energy, which it uses for cutting and emulsifying power, while at the same time providing irrigation and aspiration. The Phaco tip has three major functions: • The primary function of the phaco tip is to convey the generated ultrasound energy to the nucleus, to be used for cutting and emulsification of the nucleus. • The secondary function, which is very important, is to hold and stabilize the nucleus for phaco maneuvers and to act as an additional pivot and fulcrum point. It is this secondary function, which is so vital for good phacoemulsification. • The tertiary function is to provide a pathway for the outflow of irrigating solution, nucleus fragments, cortical remnants and other debris, while at the same time permitting an irrigation inflow via the silicone sleeve that sheaths the tip. It also prevents turbulence and cavitations via the newer phaco tips and silicone sleeves. BASIC PROBLEMS WITH A PHACO TIP The present day phaco tips, for all their sophistication have two major problems. Inadvertent Capsular Contact Inadvertent capsular contact can occur fairly easily as the tip is the part, which is closest to the capsule, and since the entire aspiration of cortical and nuclear debris is limited to the tip only. Present day requirements of high suction to hold the nucleus for chopping obviate the safety measure of keeping far away from the capsule, as the tip has to penetrate deep in the nucleus to hold it. The possibilities of surge when the tip suddenly releases hold may lead to inadvertent capsule break, with catastrophic results. Blockage of the Bore of the Tip Naturally any device that uses vacuum to suck up bits and particles is liable to get blocked some time or the other. The ultrasound phaco tip normally does not get blocked because the ultrasound energy clears the throat of the tip and keeps it open. However when handling hard cataracts or using inadequate ultrasound energy, the tip may get blocked. There are two problems with the blockage of the tip, which need to be considered in detail. Sudden Collapse of the Anterior Chamber due to Surge Surge is the development of sudden high suction that develops when a blocked tip suddenly opens up. There are various devices designed to eliminate or control surge.

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Enhanced Irrigation Input The simplest way is to have the third port, i.e. a third line at the 6 O’clock position through a side tube (Blumenthal) attached to a drip stand. The moment suction breaks, an increased quantum of inflow via the side port will stabilize the chamber and control the surge. Another simple way is to increase the inflow via the irrigation line by having a double drip stand connected with stiff, wide-bore TUR tubing (Mehta, 1997). Urogenital surgeons use it for prostatic transurethral resection. This wide bore tube commercially available, sterile disposable tubing enhances the flow when a sudden break occurs. A similar system using conjoint tubing has also been described as the Bangkok system. The Ocusystem IIart utilizes the double bottle set-up for the surge prevention fluid venting system. Usage of a computerized pump slowdown The newer computerized units like the Alcon Legacy, the Allergan Prestige and Sovereign, and the Storz Millennium, use a computer-controlled program. The moment the vacuum breaks in the tip, to prevent surge development and the computer immediately slowing down the peristaltic pump (Alcon and Allergan) , or the rotor ( Storz) for a few seconds, which compensates perfectly, automatically decreases chamber collapse, the vacuum. It is this “fluidic control” that makes all the difference in a dangerous situation. The use of diaphragm drum The Opticon Pulsar and the Mentor SIS system use a diaphragm drum. The sudden development of surge is partially damped down by the diaphragmatic membrane movement. Surgin Co in USA, has also taken out small flexible round thin walled sump, which can be fitted at the end of the phaco handpiece and which would thus work with any instrument. Corneal/Scleral Burns The phacoemulsification tip remains cool by the irrigation inflow passing over the surface of the phaco tip conducted via the silicone sleeve, and partially, by the continuous outflow of the aspirate fluid (with nuclear, cortical and capsular debris). The silicone sleeve goes through the corneal opening and is likely to get occasionally kinked or even compressed if the opening is not exact and perfect. When the flow of the irrigation is slowed down or stopped, and ultrasound energy is turned on, corneal /sclera burns due to the overheated phaco tip, can easily occur. The scleral is a little resistant to burns but the cornea, unfortunately is not. Once the burn in the cornea occurs, the cornea remains open like a cantilevered bridge and will not seal necessitating a suture at the end of surgery and subsequently inducing astigmatism. WHERE LIES THE ANSWER TO THESE PROBLEMS? Preventing burns is fairly easy by modifying the tip as has been done by the Storz Microseal handpiece which utilizes a dual infusion sleeve, the inner rigid sleeve in between the silicone sleeve and the ultrasound titanium tip. The Ocusystem IIart uses rigid clear polysulfone sleeves, which negate chances of a corneal burn. The

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Surgin tip has a dual ply mesh material in the sleeve that prevents occlusion and is virtually impossible to pinch off the flow and produce a burn. The problem of surge control is, however a different matter. The obvious answer is to modify the phaco tip to obviate the problem of a pure tip-based suction and aspiration of the emulsified debris. If the tip can be altered so that it maintains the ability to hold and cut, while minimizing sudden surge, then the risk of capsular break can be significantly reduced, if not eliminated. THE MULTIPORT PHACO TIP: ITS DESIGN The salient features are two side ports 0.50 mm behind the apex of the 15-degree phaco tip (Fig. 43.1). The side ports, each with a width of 0.3 mm are beveled inwards, at 30-degree angle, to prevent any capsular catch (Fig. 43.2). The phaco tip is also beveled inwards, which improves its cutting and holding ability.

Fig. 43.1: Showing the side ports

Fig. 43.2: An other view of side ports

How does the New Multiport Phaco Tip Function? • The suction, at the tip, which though required for the aspiration of the emulsified matter, is responsible for the capsular damage in phaco. The suction is now divided between the tip and the side ports. The area of the side port almost equals the area of the tip, hence tip suction is markedly minimized. The capsular hold can only take place when all the three ports are occluded simultaneously. • The side ports are only 0.5 mm away from the tip. Thus when it is required to hold a nucleus to chop it or to maneuver it, one needs to only bury the tip beyond the side ports, i.e. 0.8 mm (Fig. 43.3). This entry of less than a millimeter is more than adequate to occlude all the three ports, thus generating suction for holding the nucleus in a manner similar to a standard single port tip. • Since there are three ports, and since most blockages of the phaco tip only occur at the tip, surge is very unlikely to develop, with its risks of chamber collapse and capsular tears. • The presence of the three ports diminishes the tip suction, but at the same time gives three ports for the aspirants, thus cleaning the peripheral cortex simultaneously. As a matter of fact with this divided suction, if the phaco suction

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Fig. 43.3: Phaco tip being impacted into lens prior chopping

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Fig. 43.4: Chopping proceeding on impacted tip

is turned down to 60 mm vacuum, one can almost use it as an irrigation/ aspiration device. At this pressure rating the tip can be moved over the capsule without occluding and breaking it. • The novice, or, for that matter, even the seasoned practitioner, when he or she accidentally goes through a nucleus, is likely to break the posterior capsule, almost immediately. The advantages of using this tip as a “trainer” tip for newcomers to phaco thus become obvious. Training residents become far easier. Rather than restricting the student to only specific phaco techniques, he or she can practice all the techniques with a reasonable modicum of safety. The multiport phaco tip thus functions like a safety net, and most important of all, the patient does not have to suffer for the student’s error. Advantages of the New Multiport Phaco Tip The new multiport phaco tip works like a regular 15-degree phaco tip. It holds the nucleus identically to a regular tip, permitting stop and chop, phaco chop, tangential chop and any variant of these techniques (Figs 43.4 to 6). It aspirates the emulsified debris much faster than the normal, unventilated phaco tip. Even

Fig. 43.5: Hard nuclear fragment being phacoemulsified

Fig. 43.6: Final fragments being fed into tip

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deliberate touch on the capsule, with the ultrasound on, does not break the capsule. Therefore there is a significantly enhanced safety with the chop procedure with no risk of capsular break in sudden fluid pressure imbalances. It is thus ideal for the novice, and even the, occasionally distracted, experienced, phaco surgeon. It is possible to remove the nuclear girdle very easily and even a fair quantum of cortical debris. The Multiport Phaco Tip: A New Teaching Tool The greatest problem with phaco is the inordinate complications with accelerated teaching methods. The most common point of rupture of the posterior capsule is during grooving, especially the deeper part of the nucleus, or when entering the nucleus to hold it for chop procedures. A novice, rather than making a single ultrasound burst to penetrate and thus hold the nucleus preparatory to chopping it, makes a timid entry which only makes a small hole, inadequate to hold the nucleus. He or she then makes another timid entry, again inadequate, but which makes the hole in the nucleus deeper and broader. Despairing, he or she gets bold, enters via the same small hole, turns on the U/ S and promptly goes through the nucleus itself. With this tip, even if he goes through the nucleus, provided he had hydrodissected it well, there is no risk of capsular damage. The Multiport phaco tip permits all the standard phaco maneuvers like, rotating the nucleus with the phaco tip in the eye, flipping a lens over in the penultimate phaco flip, perfectly safe, provided the student exercises a modicum of care and restraint. The latent problems when one has to teach a student or a novice the art of phacoemulsification. The tutor has to first demonstrate the surgery to the student, make sure he or she knows the concepts well, and has seen enough phaco surgery on a video to at least know the facts and how to manage a problem if it occurs. He or she should also have spent time with the actual machine on pig’s or goat’s eye so that before he or she touches human eye he or she is as well trained as is possible. The tutor then has to, literally, hand-hold the pupil till his or her natural, sometimes deeply latent, abilities take over. It is a fact that no matter how many cases are seen prior learning phaco, there is no substitute to actual practice. The only way to teach phaco is with the phaco handpiece in the student’s hand. No matter how good the tutor, and no matter how careful he or she is, complications will occur. The question is to anticipate them and to minimize them. The new Multiport Phaco Tip is thus a God-send, and will minimize complications very significantly. Any procedure, which can assist easier learning, which is safe for the patient, will make a world of difference. Thus this Multiport Phaco tip which has inherent safety features is very important, not only from the learners view point, not only from the tutors but most important from the patients. The only disadvantage, if it can be called that, is that it slows down the Phacoemulsification procedure a bit, which is an advantage as far as the learner is concerned.

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How does this Tip Differ from Other Multiport Tips? Alcon for its Legacy Unit, makes a tip with an opening almost 14 mm back from the tip, with the idea that when the tip obstructs, rather than the full suction being applied to the tip, part of the vacuum is diluted by by passing the blocked tip via the fine 0.1 mm opening. A good concept, a wrong application. It has no function, as the surge is already compensated by the superb fluidics of the Alcon Legacy and by itself the tip is useless to use as a trainer tip. My original paper on the multiport tip had been presented at the All India Ophthalmological Society conference in January 1997, a little more than 3 years ago. At that time I had thought it was a good idea to cut down on accidental capsular breaks, but had not considered it as a “trainer” phaco tip till I discovered the benefits almost a year down the line. A few months later another paper had been presented at the ESCRS meeting, by a French author, along the same lines. This tip, had a single port almost 3.5 mm away from the tip and on the upper surface of the tip termed as a ‘magic hole’. This modification again does not in any way work as a trainer tip. Availability of the Phaco “Trainer” Tips The phaco trainer tips can be made on any tip, for any emulsifier. At present it works on both the author’s Opticon Pulsar as well as the Alcon Legacy. The tips at present are being ground by “Ingenious Medical Devices “ in India. You need to send your phaco tips, which are modified and shipped, back to you, but they can be made by any competent workshop anywhere in the world. Though the author has patented the Multiport Phaco tip, anyone is free to make and use the tip. CONCLUSION Phaco is, undoubtedly the cataract surgery of the new millennium. Surgeons as well as patients demand it. Even the rural patients have tasted its benefit and ask for it by name, and literally, clamor for it. The results once experienced are difficult to equal by any other method. This new phaco tip seems to be the answer to most of the vexing problems of training a legion of new surgeons, the art of Phacoemulsification. The new tip has made this already superb procedure, better, highly predictable, and most important of all, safe. The important factor of the learning curve with its attendant problems can be offset by the use of this simple, yet beautifully functional, and efficient multiport trainer phaco tip. FURTHER READING 1. Mehta KR: Pitfalls encountered in 1500 consecutive posterior chamber implant. All India Ophthl Soc Proc 165-66,1986. 2. Mehta KR: Shelve and shear phacoemulsification. All India Ophthl Soc Proc (Mumbai) 1995. 3. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997.

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4. Mehta KR: Intralenticular phacoemulsification—a new technique. Proc of SAARC Conference, Nepal, 1994. 5. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 6. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994. 7. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification poster presentation at the ASCRS Conference, Seattle, 1999. 8. Mehta KR: The new multiport phaco tip, Proc All India Ophthalmological Society, Cochin, 1999 (In print).

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John J Alpar

Intraocular Lenses Dislocated into the Vitreous

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Intraocular lenses (IOLs) of different designs may dislocate into the vitreous. Smiddy and Flynn placed the incidence of this complication between 0.2 percent and 1.2 percent and stated that dislocation may occur at the time of the surgery to many months after surgery, especially after trauma.1 Two of their reported cases were discovered 66 months after surgery. All articles consulted listed the possibility of leaving the IOL in the vitreous cavity, correcting the optically aphakic condition with an anterior chamber (AC) angle fixed IOL or with a contact lens.1-10 The difficulty of late removal of the dislocated IOL in the presence of an AC fixed IOL was discussed by Williams DF, et al.7 Repositioning of the dislocated IOL and suturing it to the iris with a modified McCannel suture to the sclera were reported by Smiddy WE and Flynn HW Jr,1 Sternberg P Jr and Michels RG,5 Stark WJ, Michels RG and Bruner WE9 or to the sclera as reported by Smiddy WE,8 Lewis ML, Gass DM and Spencer WH,12 and Croxatto JO, Galentine P, Cupples HP, et al.13 Although today’s vitreoretinal instrumentation and surgical techniques have reached a level that removal of the IOL prevents relatively low incidence of complications, still hemorrhage, retinal detachment (RD), even sympathetic ophthalmia11 (albeit in very few cases 0.06 to 0.1%14) may occur. Gass in 1980 reported “a recent survey of 23 departments of ophthalmology showed that 10 of the 48 histologically confirmed cases of sympathetic ophthalmia that developed in the last five years occurred after vitrectomy,” quoted by Croxatto JO, Galentine P, Cupples HP et al.13 Jacobi and Krey2 in 1983, stated that “the dislocated IOL may be well tolerated although optically useless.” Brockman et al3 describe a case of a posterior chamber

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intraocular lens (PC IOL) dislocating on the table and a second sulcus-fixated PC IOL implanted immediately, leaving first in the vitreous. “The dislocated IOL appeared to cause no problems, except of occasionally creating a relative field defect in the left eye when the patient was lying down.” Balent et al4 surrounded the dislocated IOL with retinal photocoagulation and implanted a second AC IOL. “No adverse reaction to the dislocated implant was noted.” Sternberg et al5 stated that “one approach is to leave the dislocated IOL in the vitreous cavity. Optical correction can be provided by a contact lens or by placement of a second IOL in the anterior chamber...though we have not yet seen serious complications from a dislocated IOL, it seems likely that a mobile* IOL might cause retinal...damage.” Flynn et al6 stated that “dislocated IOLs may be well tolerated in the vitreous cavity for extended periods,” and that “the indication for surgical management of subluxated or partially dislocated IOLs is controversial.” Williams et al7 recently said that “if* the dislocated lens is in stable position outside the visual axis and unaccompanied with other complications, it may be well tolerated in the vitreous cavity for an extended period.” A CASE REPORT* Historically, she had poor postoperative vision since first postoperative visit. The author saw her seven months postoperatively with a retinal detachment. A 57-year-old woman had uneventful phacoemulsification and implantation of a Pharmacia and Upjohn +23.5D C loop foldable PC IOL, Model 912. At the end of the surgery the lens was well-centered and in the capsular bag. The next day the lens was still in the same position. The day after, the patient called complaining of seeing a line in the field of vision. Examination with dilated pupil showed the IOL being dislocated into the vitreous. There was no history of trauma. The patient was advised of this finding and was told of the following options: • There was no urgency in doing anything except watching the situation carefully while the postoperative reaction cleared up on topical medications. • Once the eye quiets down she can have the lens removed the replaced with an anterior chamber angle lens, or the posterior chamber lens can be sutured to the sclera. • The original lens can be retrieved from the vitreous in a closed system and repositioned and sutured to the iris with a McCannel suture. • If there is no significant visual disturbance, the IOL may be left alone in the vitreous and the patient fitted with a contact lens. • The lens can be left in the vitreous and a secondary implantation of an anterior chamber angle fixated lens can be done. Again, the patient was advised that, although close observation is a must and in case of worsening of the condition (such as decreased vision, flashing lights, visually disturbing lines, floaters, increased inflammation of glaucoma, etc) surgical intervention may become necessary, a dislocation alone does not require emergency surgery. * Emphasis added by author

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The patient chose to go to another ophthalmologist who told her that “the removal of a dislocated IOL was a surgical emergency” and sent the patient off 120 miles to a retinal surgeon with a request that the patient should be sent back after the lens has been removed so that the referring doctor could put in an anterior chamber angle fixated lens. The handling of this case initiated a search of the literature and a consultation with 30 very experienced and well-known anterior segment and retinal surgeons from different countries and a review of the office records between 1973 and 1998. The questions put to the consultants were: Should, in your opinion, posterior chamber lenses which dislocated into the vitreous cavity be: • Removed? • Repositioned and sutured to the sclera? • Repositioned and sutured to the iris: • Removed, but replaced with an anterior chamber lens? • Left in the vitreous and use another type of lens (iris claw, chamber angle, etc.)? and • How urgent is such an operation in the absence of any movement of the lens, any retinal irritation, any vitritis, or any macular problem? Of the 30 consultants, 25 were anterior segment surgeons and 5 were retinal surgeons. 17 were American, 2 were German, 1 was South African, 5 were from Great Britain, 2 were Canadian, 1 was Japanese, 1 was Indian, and 1 was from The Netherlands. With the exception of one Japanese colleague, no consultant felt that the removal of the IOL was urgent. One American retinal surgeon went as far as to say that the urgency of the operation depends on how hungry the retinal surgeon is and how many children he has. One American anterior segment surgeon said that all such lenses should eventually be removed, and one said he has several retinal surgeons in his group so the lenses might just as well be removed. PERSONAL EXPERIENCE Between 1973 and 1998 28 patients were seen by the author with intraocular lens dislocations into the vitreous. 8 patients were originally operated by the author and twenty came from the practice of other ophthalmic surgeons. The lens styles were: Binkhorst’s four loop lens Medallion two loop lens Choyce Mark VIII lens (all following intracapsular surgery) Posterior chamber silicon three piece lens PMMA three piece J loop lens PMMA three piece C loop lens PMMA one piece C loop lens For a total of

2 1 1 2 9 11 2 28

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Time of the diagnosis of dislocation was: On the table: PMMA three piece 1 Next day: PMMA three piece 1 Ten postoperative days: PMMA three piece (one trauma) 3 Six weeks postoperatively: PC lens 2 Six months postoperatively: PC lens (trauma) 1 Not sure of the time (other surgeon’s patients) 20 (Of the 20 patients, one had a retinal detachment (3 piece PMMA two loop lens) The treatment approaches chosen were as follows: • Binkhorst’s four loop lens ICCE repositioned in closed system. Anterior loop sutured to iris: 2 • Medallion two loop lens ICCE repositioned in closed sytem. Loops sutured to iris, McCannel suture: 1 • Choyce Mark VIII lens ICCE left in vitreous. Another Choyce Mark VIII lens implanted: 1 • PMMA three piece lens moving in vitreous: J loop—4 C loop—3 • IOL removed and replaced with anterior chamber angle fixed lens: J loop—4 J loop—6 • Sutured to the sclera: C loop: 1 • PMMA C loop, retinal detachment present, removed not replaced: 1 • Lenses were left in vitreous and anterior chamber angle fixed lens implanted: PMMA—7 PC—2 • Lenses were repositioned in closed sytem. There was PMMA J loop—1 enough capsular support present, but the lenses were C loop—2 sutured to the iris with McCannel sutures. Four PMMA three piece lenses were stable in the vitreous. They were left in situ. Optical correction was achieved with contact lens. The time between the original surgery and IOL implantation and the second surgery (if any) was six weeks to twelve years, mean four years. The complications after the first surgery cataract extraction included: Lens flopping in the vitreous: CME: Visual symptoms (lines, floaters): Retinal detachment:

7 2 4 1

Complications after the second surgery lens repositioned with replacement were: RD two weeks after scleral suture and transient CME: 3

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Visual acuity • One year postoperatively, lens in situ in vitreous, contact lens: 20/40—3 20/20—1 • PMMA three piece C loop lens, RD present, IOL removed not replaced-finger count • Flopping IOL removed, replaced with anterior chamber: 20/40 to 20/30J loop—6 • Repositioned in sulcus, McCannel suture. Transient CME (end vision): 20/50 to 20/30J loop—4 • Lens sutured to sclera, RD after all surgeries: 20/80J loop—1 • Choyce Mark VIII lens left in vitreous, anterior chamber lens implanted: 20/40+-1 • PC lens left in vitreous with anterior chamber lens implanted: 20/40 to 20/30-9 Of course the review of the quoted literature, as well as the consultants, also emphasize that complications (mainly CME, retinal breaks and RD) might occur and that uncorrectable and intolerable visual problems, in addition to aphakia, can be present. Therefore, one cannot emphasize enough that not all cases are acceptable for leaving the IOL in the vitreous, whether one corrects the aphakia with contact lens or with secondary implant. The author’s experience, as well as the experience of the consultants and the described or implied literature by the articles quoted, suggest the following caveats: • The patient must be fully informed of the condition, the possible complications and their symptoms, the treatment options and their possible consequences. Only the patient can make the ultimate decision what therapeutic course should be taken. • The patient must be reliable to report any changes in his/her visual condition, appearance of the eye, sensitivity to light, pain, discomfort, etc. however mild, immediately to the surgeon. • The patient must be in good health, should not have high blood pressure which might be aggravated by anxiety, should not have diabetic eye disease, lattice degeneration of the retina, large macular drusens, etc. • It is preferred that the vitreous should be quite formed, not liquid, and that the lens cannot flop around. • The patient should be willing and able to be followed very closely every month at the beginning and later every six months, at least, with the pupil dilated to monitor and document the position of the IOL, the condition of the vitreous and of the retina. • The surgeon should have fluorescein angiography and fundus photography capabilities to follow even subtle changes of lens position and of the retina. • The surgeon should have skill in vitrectomy techniques (almost all manipulations of the dislocated lens require vitrectomy) or have a close working relationship with a retinal surgeon.

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• The patient must not have glaucoma or uveitis and must be checked on every visit for possible development of such conditions. • If a retinal surgeon (as it is preferred) removed the dislocated IOL, it should be him/her who inserts the secondary implant. To send the patient back to the anterior segment surgeon is to expose the patient to a third operation and to all its possible dangers. Unlike a dropped nucleus during phacoemulsification which should be removed within a week or so, removing (and especially repositioning) the dislocated IOL from the vitreous cavity is not an urgent matter. Smiddy and Flynn1 “found that waiting at least two weeks after the cataract surgery allowed for capsular fibrosis which was beneficial for providing IOL support.” CONCLUSION Undoubtedly, vitrectomy surgery and instrumentation have progressed during the past ten or so years to a level where the removal of an IOL dislocated into the vitreous is much safer and has fewer serious complications than before. IOL technology has also improved making the IOLs lighter and more biocompatible than in the past. Hence, in carefully selected cases, leaving an IOL in the vitreous is a very viable treatment option. Optical correction of the resulting aphakia can be achieved with a contact lens or with a secondary IOL implant of the proper style that would remain stable in the visual axis. (The Artisan® lens, formerly known as an “iris claw” lens, seems to be an excellent choice for secondary implants). If the choice is to remove the dislocated IOL, the surgery is almost never urgent. The reposition or extraction of the dislocated IOL always requires vitreous surgery. If this is performed by a vitreo-retinal surgeon, he/she should be the person to implant the secondary lens, thus saving the patient the expense and the risk of yet another (third) surgery. REFERENCES 1. Smiddy WE, Flynn HW Jr: Management of dislocated posterior chamber intraocular lenses. Ophthalmology 98: 889-94, 1991. 2. Jacobi KW, Krey H: Surgical management of intraocular lens dislocation into the vitreous: Case report. Am Intra-Ocular Implant Soc J 9: 58-59, 1983. 3. Brockman EB, Franklin RM, Kaufman HE: Visual disability resulting from a dislocated intraocular lens. J Cataract Refract Surg 19: 312-13, 1993. 4. Balent A, Civerchia L: The double implant: Alternative management for intraocular lens dislocation. J Cataract Refract Surg 12: 79-80, 1986. 5. Sternberg P Jr, Michels RG: Treatment of dislocated posterior chamber intraocular lenses. Arch Ophthalmol 104: 1391-93, 1986. 6. Flynn HW Jr, Buus D, Culbertson WW: Management of subluxated and posteriorly dislocated intraocular lenses using pars plana vitrectomy instrumentation. J Cataract Refract Surg 16: 51-56, 1990. 7. Williams DF, Del Piero EJ, Ferrone PH et al: Management of complications in eyes containing two intraocular lenses. Ophthalmology 105: 2017-22, 1998. 8. Smiddy WE: Dislocated posterior chamber intraocular lens: a new technique of management. Arch Ophthalmol 107: 1678-80, 1989. 9. Stark WJ, Michels RG, Bruner WE: management of posteriorly dislocated intraocular lenses: Ophthalmic Surgery 11: 495-97, 1980.

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10. Johnson MW: Dislocated PMMA, silicone IOLs need careful management. Ophthalmology Times 24: 28, 1999. 11. Lakhanpal V, Dogra MR, Jacobson M: Sympathetic ophthalmia associated with anterior chamber intraocular lens implantation. Ann Ophthalmol 23: 139-43, 1991. 12. Lewis ML, Gass DM, Spencer WH: Arch Ophthalmol 96: 263-67, 1978. 13. Croxatto JO, Galentine P, Cupples HP et al: Sympathetic Ophthalmia after pars plana vitrectomy-lensectomy for endogenous bacterial endophthalmitis. Am J Ophthalmol 91: 342-46, 1981. 14. Complications of ocular surgery. International Ophthalmology Clinics Boston Fall: Little Brown and Co 32: 210, 1992.

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Amar Agarwal

FAVIT: A New Technique to Manage Dropped Nuclei

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INTRODUCTION Phacoemulsification has changed cataract surgery. Today the trend is to move into smaller and smaller incisions. Laser cataract surgery has made the incision from the 2.6 mm of phaco incision to 1.8 mm. Phakonit has even reduced it further to 0.9 mm. Not only have the incisions reduced, eye surgeons have moved from peribulbar to parabulbar and topical anesthesia cataract surgery. Today with the latest No Anesthesia Cataract Surgery, cataract removal has really reached a new dimension. With all these new developments occurring another problem is also occurring and that is a nucleus drop. Just as a rose plant has a beautiful rose with the thorns so also phaco has this real bugbear. The solution to this problem is to manage this complication well. Various techniques have been used to remove dropped lenses like usage of perfluorocarbon liquids or the use of a needle. The author has removed dropped nuclei by all these techniques. He has then devised his own technique of removing dropped nuclei, which is a totally new concept. He has named this technique as FAVIT. FAVIT—A NEW METHOD TO REMOVE DROPPED NUCLEI Basics Before we move into the technique of FAVIT, let us remember that phaco should not be done in the presence of vitreous. The reason is that if the vitreous fibrils get sucked into the phaco probe it will also tug on the retina, which can lead to a tear in the retina and retinal detachment.

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Peristaltic Vs Venturi Pump Normally, when we perform three port vitrectomy for macular holes or any other vitreoretinal pathology we use the vitrectomy machine, which has a venturi pump. In this one hand holds the endoilluminator and the other the vitrectomy probe. This vitrectomy probe can do two functions—first of cutting and the second of aspiration. The third port has an infusion cannula through which BSS (fluid) flows continuously. If we use the same technique when we are managing dropped nuclei we have a problem. We have to make another port—in other words a third port for the fluid to pass through with the infusion cannula. The problem is that we perform clear lens incisions under topical anesthesia. These cases will have to undergo a conjunctival cut and a sclerotomy to fix the infusion cannula. All this will have to be done under a peribulbar block. To solve this problem we decided to use the peristaltic pump in our FAVIT technique. In this the advantage is that the vitrectomy probe has three functions— first of cutting, second of aspiration and the third of infusion. In other words, there is an infusion sleeve present which allows fluid to pass through. Another advantage is that every phaco machine (e.g. Alcon) also has a vitrectomy set-up. If one is an anterior segment surgeon, he or she does not have to buy a separate vitrectomy machine. A peristaltic vitrectomy machine comes with the phaco machine. The disadvantage of the peristaltic pump while performing vitrectomy is that if you take your foot of the pedal while aspirating it will still aspirate for some time. Whereas in a venturi system, the moment you take your foot of the pedal the suction immediately stops. The point is that if you are doing vitrectomy with the peristaltic pump you should be careful that you do not create a retinotomy. In the Storz Machine, Both Virectomy and Phaco are in the Venturi System so There is no Problem Favit Technique Let us now look at the technique of FAVIT. If you are doing phacoemulsification, you are either doing a clear corneal incision or a scleral incision. In Fig. 45.1: Dropped nucleus. Nucleus lying on the the left hand you have a chopper or a retina due to a posterior capsular rupture straight rod. If during surgery, there is a posterior capsular rupture and the nucleus drops into the vitreous, this nucleus will generally go and lie on the retina over the disc and macula (Fig. 45.1). First of all, go in with an irrigating aspirating probe and remove the cortex. Do this first, otherwise when you perform vitrectomy your visualization will get hampered with the cortex.

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Then immediately convert to a vitrectomy set-up. Ask the assistant to fix the vitrectomy probe to your phaco machine set-up. In other words you will be using a vitrectomy probe with a peristaltic pump. Now, pass the vitrectomy probe through the clear corneal incision or through the scleral tunnel incision you had made. This probe will pass into the anterior chamber and then pass through the posterior capsular rupture into the vitreous cavity. In the other hand hold Fig. 45.2: FAVIT technique. Note the endoilluminator and the vitrectomy probe with infusion sleeve are an endoilluminator and pass it through passed through the corneal incisions into the vitreous the side port opening. This will also go cavity through the posterior capsular rupture through the posterior capsular rupture into the vitreous cavity (Fig. 45.2). Start the anterior vitrectomy. This can be done with the aid of the operating microscope light. Once the anterior vitrectomy is done, move downwards to perform a mid vitrectomy. For this off the microscope light and use the light of the endoilluminator. At this time ask your assistant to place a contact lens on the cornea. Any contact lens can be used which is normally used for three port vitrectomy. The assistant should be Fig. 45.3: Vitrectomy is done so that the vitreous is careful while holding the lens because converted to fluid (BSS). Vitrectomy contact lens is the vitrectomy is being done through a placed on the cornea clear corneal approach. The problem is that your vitrectomy and endoilluminator will be occupying a little bit of space of the cornea. So the assistant should push against your hands otherwise the visualization will be very bad. Once a midvitrectomy has been done, proceed to do a posterior vitrectomy. Clear all the vitreous fibrils around the nucleus. Watch the nucleus. There should be no vitreous fibrils around it. Another point one should note is to check the movement of the nucleus. When vitreous is around it the nucleus will not move much. When the vitreous gets cleard, the nucleus will start moving around a lot. This indicates that the nucleus is free of vitreous attachments (Fig. 45.3). Once the nucleus is free of vitreous attachments, bring the vitrectomy probe out. Then shift to a phaco probe (Fig. 45.4). Once again in a phaco probe fluid will also pass through it. So, pass the phaco probe through the clear corneal incision and pass the endoilluminator through the side port. Keep the settings as 50% phaco power, 50 mm of Hg suction and 18 ml/minute flow rate.

FAVIT: A NEW TECHNIQUE Once the phaco probe is over the nucleus apply only suction. The nucleus will then come towards the phaco tip. At that stage, when the nucleus touches the phaco tip apply a very small burst of phaco power which will embed the nucleus into the phaco tip (Fig. 45.5). This is just akin to doing a phaco chop when you embed the nucleus in the phaco tip. Once the nucleus gets embedded, it has been impaled. Lift the phaco probe anteriorly. The nucleus will also get lifted (Fig. 45.6). Bring the nucleus anteriorly above the iris. The nucleus will not fall back as it has been impaled in the phaco tip. All this time, keep your foot pedal in position 2. Position 3 is used only at one time for a fraction of a second when you are impaling the phaco tip into the 4 nucleus. When the nucleus is brought anteriorly, use the left hand with the endoilluminator to guide the nucleus above the iris (Fig. 45.7). At this stage, check the status of the nucleus. If the nucleus is not very hard, remove it with phaco in the anterior chamber. Do not use pulse mode and do not chop the nucleus. If you use pulse mode the nucleus might fall back, as there is a time in the pulse mode when ultrasound is not being used. Do not chop or divide the nucleus otherwise one-half might fall back into the vitreous cavity. Use continuous mode ultrasound and keep on nibbling the nucleus like a rat eating a piece of cheese. Start nibbling from one side till the whole nucleus is removed. If the

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Fig. 45.4: Phaco probe is now passed into the eye

Fig. 45.5: Phaco tip embeds the nucleus

Fig. 45.6: Nucleus is lifted up by the phaco probe

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nucleus is very hard, extend the incision and remove the nucleus manually. Once the nucleus has been removed, go in again for a vitrectomy to see if any cortex or small fragment is left behind. If it has been left behind, remove it. Perform an iridectomy with the vitrectomy probe. Then inject viscoelastics and implant a 6.5 mm non-foldable PC IOL in front of the rhexis. Apply suitable sutures.

Fig. 45.7: Nucleus is brought into the anterior chamber. It can be removed manually (If a hard cataract) or by phacoemulsification (If a soft cataract)

Anesthesia If you have done your phaco under peribulbar, there is no problem. The case can just be continued and the nucleus retrieved. If you have done the case under topical, one can perform the FAVIT technique under topical anesthesia also. If you are not very confident one can do a parabulbar anesthesia. In this just make a nick in the conjunctiva in the superior temporal quadrant. Take a syringe with xylocaine and a cannula. The cannula can be the one you are using for injecting viscoelastics. This cannula is then passed on the side of the globe till it reaches near the optic nerve. Inject one ml of Xylocaine. Wait for a couple of minutes and then start the vitrectomy. The patient will not have any pain. DISCUSSION Nucleus drop is a common complication occurring when surgeons learn phacoemulsification.8 The nucleus cannot be left in the vitreous cavity because it incites a chronic inflammatory reaction, glaucoma and subsequent drop in final visual acuity.3,4,810 Popular among the treatment modalities presently done is anterior floatation of the nucleus using perfluorocarbon liquids,1,2,11,12 especially in the management of hard nuclei. After a vitrectomy, perfluorocarbon liquids float the nucleus anteriorly because of their high specific gravity and retinal damage is minimal.2,12 Apart from the high cost, it necessitates a third port for infusion during vitrectomy and needs to be completely removed from the vitreous after the procedure, because it risks toxic effects on the retina, corneal decompensation and glaucoma. A vitrector3,5,8,10 is an effective method of removal of retained lens matter and is helpful in resolving chronic lens fragment induced persistent uveitis and glaucoma. This necessitates three ports of entry and is difficult in cases of hard nuclei and risks retinotomy.5 Fragmatome dissolution,6 another popular technique also requires three ports of entry and risks retinotomy, especially in cases of dense nuclear sclerosis. A three port vitrectomy combined midvitreous phacoemulsification,7,9,13 though safe to the cornea, risks ultrasound induced cystoid macular edema, retinal damage,12

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and surgical time is prolonged due to repeated nucleus fall back during the procedure.2,13 We believe FAVIT provides several advantages over currently used techniques. All the above mentioned techniques use a three port vitrectomy through the pars plana. Ours is a two port core vitrectomy using the existing ports (corneal/scleral tunnel and chopper side port) of the primary phaco procedure. So, in FAVIT, there is no separate conjunctival incision, sclerotomy and its complications like choroidal effusion. In addition, the surgery can be continued after the nucleus drop, as the changeover time is short. We could perform a two port vitrectomy because our vitrectomy probe was connected to a peristaltic pump. This probe served three functions: infusion (through the infusion sleeve around it), cutting and aspiration. Normally, when vitrectomy is performed, a vitrectomy machine with venturi pump will be used. In this, one hand holds the endoilluminator and the other, the vitrectomy probe. This vitrectomy probe with the venturi unit does only two functions: cutting and aspiration. A third port for an infusion cannula is needed. As phacoemulsification cannot normally be done in the vitreous cavity because of risk of vitreous incarceration4,6 we first converted the vitreous gel into fluid by performing the two port core vitrectomy. While impaling the nucleus with phaco, it was brought up to the port by suction and there was no thrust on the retina as it now was in a fluid-filled cavity. The chances of an accidental retinotomy were minimal because of the cushioning effect of the nucleus. As it was elevated in toto, there is no retinal risk associated with scattered nuclear fragments as in a fragmatome. The lens was brought anterior to the iris and was stabilized by the endoilluminator providing better control during subsequent phacoemulsification. This technique is fast even in dense nuclear sclerosis as the nucleus is elevated first in toto and subsequently taken out by enlarging the entry incision of the primary phacoemulsification procedure, minimizing the phaco energy used within the eye. Further, since most phacoemulsification machines are provided with a peristaltic pump, the change over is easy, and the need for a separate venturi unit is not there. This technique is cheap, and does risk any toxicity as in perfluorocarbon liquids. We find this technique safe and effective in our hands. The complication rate is extremely low and the postoperative vision is good. Only one of the eyes developed cystoid macular edema and the final BCVA was 20/40. The cornea decompensated in two eyes. A surgeon in his or her phacoemulsification learning curve performed the primary procedure in these cases and hence the decompensation could not be directly attributable to the FAVIT procedure. SUMMARY Whenever one discusses whether one can do phaco in the vitreous cavity, the answer is an absolute NO. The reason is that the vitreous fibrils get entangled in the phaco probe and as they are connected to the retina they pull on the retina producing a rhegmatogenous retinal detachment.

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What we are doing is different. We are first of all performing a vitrectomy. We have now converted the vitreous into saline or BSS depending on the irrigating fluid being used. The nucleus is now lying on the retina surrounded by fluid. In other words, the retina is akin to the posterior capsule. It is just like the nucleus lying on the posterior capsule surrounded by aqueous humor or fluid. Now, what we are doing is just taking of the nucleus like we would do it in the anterior chamber. We are using suction and then very little phaco power to embed the nucleus. The nucleus is brought anteriorly and then removed. The chances of tears occurring in the retina are not there because we have first converted the vitreous into fluid. Another point to note is since we are doing a two port vitrectomy we need not make the third port, which makes things messier. This is the reason why we use the peristaltic pump of the phaco machine and not a separate venturi vitrectomy machine. REFERENCES 1. Paris CL, Peyman GA, Blinder KJ et al: Surgical technique for managing rhegmatogenous retinal detachment following prosthokeratoplasty. Retina 11: 301-04, 1991. 2. Michael J Shapiro, Kenneth I Resnik et al: Management of the dislocated crystalline lens with a Perfluorocarbon liquid. Am J Ophthalmol 112: 401-05, 1991. 3. Lewis H, Blumenkranz MS, Change S: Treatment of dislocated crystalline lens and retinal detachment with Perfluorocarbon Liquids. Retina 12: 299-304, 1992. 4. Magherio RR, Magherio AR, Pendergast SD et al: Vitrectomy for retained lens fragments after phacoemulsification. Ophthalmology 104: 1426-32, 1997. 5. Fastenburg DM, Schwartz PL, Shakin JL et al: Management of dislocated nuclear fragments after phacoemulsification. Am J Ophthalmol 112: 535-39, 1991. 6. Borne MJ, Tasman W, Regillo C et al: Outcomes of vitrectomy for retained lens fragments. Ophthalmology 103: 971-76, 1996. 7. Lambrou FH (Jr), Stewart MW: Management of dislocated lens fragments during Phacoemulsification. Ophthalmology 99: 1260-62, 1992. 8. Kapsuta MA, Chen JC, Wai-Ching Lam: Outcomes of dropped nucleus during Phacoemulsification. Ophthalmology 103: 1184-87, 1996. 9. Gilland GD, Hutton WL, Fuller DG: Retained Intravitreal lens fragments after cataract surgery. Ophthalmology 99: 1263-69, 1992. 10. Topping TM: Retained intravitreal lens framgments after cataract surgery (Discussion). Ophthalmology 99: 1268, 1992. 11. Blodi BA, Flynn HW (Jr), Blodi CF et al: Retained nuclei after cataract surgery. Ophthalmology 99: 4144, 1992. 12. Rowson NJ, Bacon AS, Rosen PH: Perfluorocarbon heavy liquids in the management of posterior dislocation of the lens nucleus during phacoemulsification. Am J Ophthalmol 76: 169-70, 1992. 13. Movshovich A, Berrocal M, Change S: The protective properties of liquid perfluorocarbons in phacofragmentation of dislocated lenses. Retina 14: 457-62, 1994.

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Sunita Agarwal J Agarwal T Agarwal

Laser Phaco Cataract Surgery

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INTRODUCTION We are in the midst of a paradigm shift in cataract surgery today. We must either become a part of the shift or we will be blind-sided by it. Today, one of the latest developments in ophthalmology is the laser cataract surgical system. The laser cataract surgery system would entail less trauma and better rehabilitation of the patient. Pioneers For decades now we have known benefits of the ultrasound energy. Incorporated with Dr Kelman’s path breaking inroads of using this energy for the removal of cataracts has indeed reduced rehabilitation of the cataract patient. Four top opthalmologists1-7 have been working independently on the system of developing a laser to help in cataract removal. The first has been Dr Daniel Eichenbaum from USA. It has been basically due to Dr Daniel Eichenbaum and paradigm that the laser cataract removal system could be started. They have developed a machine called the laser photon. This laser photon uses the YAG laser for cataract removal. The second ophthalmologist Dr Jack Dodick introduced the use of the YAG: YLF laser for surgical cataract removal. A laser beam is a fiberoptically directed toward a titanium mirror target. The reflection produces waves of optical breakdown power, resulting in photoablation of the surface down to any depth desired. Succeeding generations of instrumentation for this technique have been modified and refined. The probes are getting thinner and thinner compared to a phacoemulsification tip.

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The third ophthalmologist is Dr Michael Colvard. The erbium (Er) laser is being used by Michael Colvard to ablate ocular tissue and its advantage is that it has maximal absorption in water. When properly directed and mirrored, as in Dodick’s approach, the laser beam is kept away from the posterior pole and the retina. Safety seems to be built into reflected laser ablation, allowing ablation without thermal injury. In Colvard’s technique, the laser beam is placed directly in contact with the nucleus of the cataract for nonpercussive cutting. By directing the beam much as one would use an eraser to wipe over the surface, the tip of the beam is directed over the ablation zone, causing optical breakdown just at the beam’s tip. The nuclear material is then removed with irrigation and an IOL is implanted. The fourth ophthalmologist is from India—Dr Sunita agarwal who has designed a new probe which incorporates laser and ultrasound in the same pico second. In 1995 we acquired our first laser machine for cataract surgery. Soon we realized the potential of capitalizing on both the energy sources together, something not thought of by any cataract surgeon at that time. And we developed a probe now capable of utilizing at the same pico second laser and ultrasound energies. Instrumentation An ordinary phaco unit would contain three functional elements, the phaco power delivered through a vibrating titanium needle of 900 microns diameter, aspiration through the needle, and irrigating fluid pump into the eye through a silicon sleeve. The laser unit consists of a key switch screwed into the laser head unit that allows the laser light to pass through a glass fibreoptic delivery and the aiming beam is also passed through the same system. This fibre is of 380 microns in diameter. The laser phaco probe developed by Dr Sunita Agarwal is patent pending as the idea of incorporating laser with ultrasound in the removal of cataracts was first developed by us and after going through many experimentations and variations we now plough the laser fiberoptic through the phaco probe making any phaco probe into a SA (Sunita Agarwal) laser phaco probe (Fig. 46.1). The instrumentation is thus in two parts: one is the phaco part that most of us are accustomed too, and the second is the laser part. These may come from the same machine or from two different machines. The Sunita Agarwal Laser Phaco Probe All probes used before this were thus designed that used laser or ultrasound in the innermost circumferential ring, with aspiration and irrigation flowing on the outer ring. This was modified by special intermediary equipment that would allow that phacoemulsification machine to still function with a laser fiberoptic delivery system in its midst. Around this is the ultrasound waves pounding along with irrigation and aspiration flowing on the outside. Thus the whole system consists of a four-function probe. The use and utilization of both energy sources makes it easier for the cataract to be blasted out of the eye in shorter time span, with less energy sources used in the eye The machine we used was the Laser Photon machine.

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Fig. 46.1: SA (Sunita Agarwal) laser phaco probe

Comparison Let us compare the phaco probe with the laser phaco probe. There is a slight embarrassment to outflow using the laser fiberoptic in comparision with a phaco probe. This is because the phaco probe is of 900 microns. The laser probe is 380 microns. This is placed inside the phaco probe, so we get only 520 microns of space left. Still the cataract is removed faster and much more safely. The laser has the capacity to photoablate 20 microns of tissue space in contact and another 200 microns is liquefied reducing the solid cataract into liquid and gas. The incision size is thus reduced as the phaco handpiece gets hot and can burn the corneal tissue. We are able to perfom laser phaco in an incision of 2 mm. The phaco incision in the cornea can get ragged with corneal burns. This rarely occurs in laser phaco as the phaco energy used is comparatively very small. As the needle held in the hand is not vibrating anymore it can reach further into the eye without any complications of iris capture or posterior capsule capture. Moreover, the laser is ineffective 500 microns away from the posterior capsule and can be used very close to the capsule. The laser used is an Nd: YAG with fibreoptic delivery and only the cataractous tissue needs to be removed thus leaving behind an epinucleus and cortex that can be easily aspirated.

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Table 46.1: Paradigm photon laser phaco system specifications Laser system

Specification

Type Wavelength Mode structure Pulse duration Burst mode Pulse interval Energy (Max) Energy selector Cone angle Aiming beam

Nd: YAG Q-Switched 1064 nanometers Fundamental temoo Less than 4 nanoseconds One, two, or three pulses per burst 20 microseconds 20 mJ per pulse 0.5 to 20 mJ variable 16 Degrees HeNe- Intensity variable to 5 mW

Table 46.2: Ultrasonic system specifications Ultrasonic system Ultrasonic capsule probe-frequency Ultrasonic phaco probe-frequency Ultrasonic phaco Probe-stroke

Specification 40 kHz 40 kHz 5-90 micron linear variable

Table 46.3: General system specifications General system

Specification

Fluidics

Peristaltic paraflow vacuum system smartpac resusable cassette system automated, programmable irrigation pole Pneumatic guillotine-50-70 cuts per minute On demand 100 surgeon case programs Video CRT and computer touch panel audio prompts for all surgical operations Air-Quiet laminar flow base 175 lbs (79.4 kg) 21W-26D-53H inches 100-240 VAC 20A 50/60 Hz

Vitrectomy cutter Bipolar diathermy Programmable Display and indicators Cooling Weight Overall diamensions Power requirements

Laser Photon In the laser photon pulsed laser energy is used to vaporize and aspirate the lens material out of the eye (Table 46.1). The most important feature of the Laser Photon is its containment of laser energy. The probe is so designed that energy used to emulsify the cataract is contained in a photovaporization chamber. The energy used to remove the cataract does not expose the contents of the eye to this energy. This gives the laser cataract removal system an advantage over conventional phacoemulsification systems (Tables 46.2 and 3), with which the ultrasonic energy can vibrate throughout the anterior chamber and involve other ocular tissues.

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The laser cataract surgery entails this specially designed probe that combines fluid handling and systems controls of ultrasonic cataract systems, now fortified with the laser energy from a solid-state pulsed laser. All three major features of the system—irrigation, aspiration and laser are simultaneously transmitted through a precise location in the eye through a single small incision. The laser is capable of ablating high water containing tissues without pigmented chromophore. This is done causing thermal injury. Its capability of performing these functions through smooth cutting makes ultilization inside the eye very favorable. Most ocular tissues are very high in their water content and the laser acts best in these surroundings. Also its high absorption by the cataractous lens makes its unwanted transmission and scatter of laser energy to adjacent and underlying tissues more controlled and precise. The laser energy is generated through a solid-state crystal and its care and service come down to a minimum. The laser is air cooled and does not require any special installation practices. Hence, it can be transported easily to the end user facility with no untoward engineering practices. In-Built The laser photon machine has in-built: • Laser • Phacoemulsification system • Vitrectomy system • Diathermy. Uses The laser cataract system is used for many purposes: • To do a capsulorrhexis This can be done with the help of the laser. One can get a neat round rhexis even in cases of mature cataracts. • To remove the nucleus A combination of laser and aspiration helps remove the nucleus. This is aided by the technique of nuclear chopping. If the cataract is very hard a combination of laser followed by emulsification can be done to make the cataract removal through a 3 mm incision. • To remove cyclitic membranes In such cases even a vitrectomy is difficult as the membrane does not get removed with the help of the vitrectomy probe. But with the help of the laser one can create a central opening in these membranes. • To create an opening in glaucoma cases This is less traumatizing than other routine antiglaucoma surgeries. • To make an inferior iridectomy in cases when vitrectomy is completed and one has to inject silicone oil. In such cases, we normally make the iridectomy with the vitrectomy probe which can by mistake convert a small iridectomy to a complete iridectomy. But with the laser photon one good controlled iridectomy can be created.

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Fig. 46.2: Plate haptic foldable IOL implanted

Surgical Procedure The technique is basically the same as in normal phacoemulsification procedures —the only difference being that here instead of ultrasound power one uses the laser energy and very rarely the ultrasound energy also. In the first step a needle with viscoelastic is injected inside the eye to distend the eye. Then a clear corneal incision is done with a diamond knife. The rhexis can be done with the laser also. We prefer to do it with a needle. After hydrodissection, the laser phaco probe is passed through the incision, with the phaco chopper in the other hand through the side port opening. The nucleus is split into small pie-shaped pieces and gradually aspirated out, followed by cortical aspiration, implantation of a foldable IOL (Fig. 46.2) and stromal hydration. In stromal hydration the BSS or saline is injected at the lips of the clear corneal wound hydrating the cornea and making it white. This helps make a better wound closure. Laser Phakonit In this we are removing the cataracts through a 0.9-mm incision using an irrigating chopper in the nondominant hand and the laser phaco probe without an infusion in the dominant hand.

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How Small will our Incisions Go Today, with more and more new technology, the laser photon will get better and better. It will make the incision size smaller and smaller so that the astigmatism amount becomes much less. By 2000 AD lasers will have become a major force in cataract removal. Foldable IOLs have definitely come to stay and they will improve day by day. Any ophthalmologist who wants to put large lenses in large incisions is bucking the tide of history. Small incisions offer the best chance for most rapid, stable visual rehabilitation of the cataract patient at the least cost, including time of impaired vision following surgery, the need for follow-up care, the attendance of relatives to take care of them to the doctor and the like. It is unclear as to how small will our incisions go. With Laser Phakonit we have broken the 1 mm barrier. Increasingly, sophisticated laser equipment is capable of giving us better utilization of energy. With the advent of the lasers, the size of the incisions will decrease. CONCLUSION Lasers would revolutionize cataract surgery. This is the modality by which one can go renal small in the incision. With this, new techniques and instruments will allow us to put IOLs through these small incisions. What the human mind can achieve as it marshals the basic and clinical sciences will continue to amaze us. Look how far we have come regarding IOLs and just imagine how far we will go and can go. REFERENCES 1. Thornton SP: IOLs, Knives and lasers—a new commitment to the cataract patient. Proceedings of Ocular Surgery News Sysmposium. 15:3, 1994. 2. Daniel Eichenbaum: Phaco is easier to do with the new laser system. Ophthalmology Times 19(13): 1994. 3. Daniel Eichenbaum: New laser phaco. Eye Care Technology 1994. 4. Jack M Dodick:L New laser phaco. Eye Care Technology 1994. 5. Vance M Thompson: A perspective on balancing the knife with the laser. Ocular Surgery News 11(13), 1993. 6. Daniel Eichenbaum: Laser probes for cataract surgery. Ophthalmology World News, 1995. 7. Daniel Eichenbaum: First computer-aided laser cataract removal system ready for clinical trials. Ocular Surgery News 13(9), 1995.

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Claude S Leon Joseph A Leon Danielle Aron Rosa

Endoscopy-Assisted Phacoemulsification

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INTRODUCTION (Figs 47.1A to C) Endoscopy is a new intraoperative method of observation useful in ocular microsurgery: it allows a sagittal or side-view and it is the only one to have such a possibility. Complementary to the operating microscope which gives only the frontal view, the endoscope brings the observation of the angle structures of the inner eye in all conditions, and mainly when opacities prevent the use of the operating microscope (for example corneal, edema, blood in the anterior segment).

Figs 47.1A to C: Endomicroscopic coupling device for endoscopy in microsurgery: Observation of the endoscopic images in the binocular of the operating microscope. (A) Operating microscope with the endomicroscope coupling device (International Patent Leon-K Storz Endoscopy). (B) Endoscopic images controlled in the operating microscope. (C) Endoscopy of the posterior chamber

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Material The endoscopic material includes the endoscopic probe (a rigid microfibroscope with an overall diameter of 20 G), its illumination system (a liquid light cable, and a 300 W Xenon cold light fountain), and a special coupling device “endoscope-operating microscope” exactly adapted for performing the endoscopy in ocular microsurgery (International patent Leon-K Storz Endoscopy). Called “Endomicroscopy”, this coupling device allows the viewing of the endoscopic images directly in the binocular of the operating microscope. The surgeon has a stereoscopic endoscopic view, avoiding the videoendoscopy on a video monitor which is not adapted for the microsurgery. The endomicroscopy is controlled with a foot pedal: the surgeon can choose the field of observation either of the operating microscope or of the endoscope. PHACOENDOSCOPY (Figs 47.2 and 3) We frequently use the ocular endoscopy during all stages of cataract surgery, during phacoemulsification and after it. Phacoemulsification under Endoscopic Control Thanks to the endoscope we have a perfect side-view of the intranuclear area. We observe the level of nucleofracture and what happens behind the iris concerning the statement of the posterior iris, the location of the ciliary crown, and the integrity of the equatorial capsular bag.

Fig. 47.2: Endoscopy during phacoemulsification . It allows to observe behind the iris: (1) Posterior iris, (2) Ciliary crown, (3) Equator of the capsular bag

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Endoscopy of the Posterior Implantation Without endoscopy, the surgeon is completely blind about the posterior chamber (location of the loops of the PC IOLs, equator of the bag, ciliary processes, zonule). The operating microscope brings only a frontal view of the operating field. It is not sufficient when we work out of the pupillary area, and when the loops of the PC IOL disappear out of the frontal observation. Where are the loops? The endoscopic investigations allow us to answer: Fig. 47.3: Endoscopic control of the location • “Out of the bag“, one or two loops have of the loop behind the iris, here in the ciliary slipped before the anterior capsulorrhexis sulcus (1) either in the ciliary sulcus or against the ciliary crown or more posteriorly There is always a direct uveal contact between the loops and the uvea. • “In the bag” for the two loops or for one only? The endoscopy confirms their exact location in the bag and it precises also and especially what are their location compared to the posterior iris, the ciliary sulcus, the uvea, the ciliary crown and the pars plana . More than 90% of the “in-the-bag” location does not avoid an indirect uveal contact it is a contact between a loop and a part of the anterior or intermediary uvea (iris, pars plicata, pars plana) through the interpolated equatorial capsular bag. Is it possible to ignore the retroiridal space during these intraoperative procedures? The problem is similar for the iridocorneal angle and the AC IOLs: thanks to our better knowledges of the angular anterior structures (gonioscopy), we perform better controlled anterior implantations. The intraoperative observations of the iridociliary angle (endoscopy) improve also our procedures in the posterior chamber (respect of the uvea, integrity of the zonule, adapted choice of the PC IOLs), and allow to understand and to foresee the postoperative period. ENDOSCOPIC SUTURE TECHNIQUES FOR PC-IOLs (Figs 47.4 and 5) In the absence of sufficient capsular support, the suture of a PC IOL in the iridociliary angle (retroiris location) is an interesting alternative instead of the fixation in the iridocorneal angle (preiris location) or on the iris (iris location). All the ab-externo or ab-interno non-endoscopic procedures are blind techniques.The ab-interno endoscopic techniques are able to give a permanent retroiridal control. When we perform a suture behind the iris, we must respect two main constraints: the first one is to have a permanent control of the posterior chamber, and the second one is to protect the tip of the needle when it passes through the anterior and posterior chambers.

ENDOSCOPY -A SSISTED P HACOEMULSIFICATION

Fig. 47.4: Endoscopic suture of PC IOL: Left— tip of the needle through the sclera (1), Right— iris (1), needle in the ciliary sulcus (2), ciliary crown (3)

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Fig. 47.5: Endoscopic suture of PC IOL: (1) iris, (2) ciliary sulcus, (3) ciliary crown, and (4) tip of the Leon’s cannula for PC IOL suture

Histopathological studies and ultrasound biomicroscopy confirm our opinion that we perform imprecise surgery behind the iris if we do not observe directly the posterior chamber during the sutures—the sutured loops are rarely in the ciliary sulcus (27%) and more frequently in a wrong location (73%) either on the iris root (19%) or on the ciliary processes or pars plana (54%). If we decide to suture a PC-IOL, the endoscopy avoids to performing blind actions in the aphakic posterior chamber. The aphakia involves an important capsulozonular collapse that we always observe with endoscopy—we call it the posterior athalamy (athalamic posterior chamber). Its consequences are—iridociliary joining and inaccessible ciliary sulcus. The ocular endoscopy brings a direct intraoperative control of the whole iridociliary angle. There are primary indications of sutured PC IOL in case of complicated cataract surgery with posterior capsular rupture, or secondary indications with or without penetrating keratoplasty. For this technique, we use: • A special endoscopic needle-holder—according to Leon—(for a one-hand and protected technique) • A straight needle of 16, 15 mm length and of 150 µ overall diameter, with a 20µ polypropylène blue monofilament (Alcon Inc., or Ethicon Inc.) • PC-IOLs with a 12,5 overall length because of the length of the ciliary sulcus less than 12 mm with a surface-modified PMMA to decrease the frequent postoperative inflammation (Heparin-Pharmacia or Fluor-Chiron surface modified PMMA), and • A high viscosity viscoelastic substance.

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Method Our endoscopic technique for suturing PC IOLs is called “ab-interno endoscopic and protected technique”. It is controlled inside-out method of the transscleral perforation . It is also a one-hand procedure: The endoscopic probe and the needle-holder are combined into one instrument. The surgeon holds with the same hand the whole instrumental functions. It allows to keep the endoscopic observation of the ciliary sulcus during the transscleral suture. The main point of this endoscopic observation is the entry site of the needle, exactly on the ciliary sulcus. It is a protected technique (needle-protected technique) because the tip of the needle is never free in the eye and completely located in a special needle-holder, coaxial and bounded to the endoscope—it eliminates all the risks of injuring the elements of the posterior chamber. It is only when the the tip of the needle-holder is positioned exactly on contact with the ciliary sulcus that the needle will be pushed out of the needle-holder thanks to a trigger, through the ciliary body (crossing the radial and longitudinal ciliary muscle fibers, avoiding the major arterial circle of the iris and the scleral spur), and then through the sclera (transcilioscleral perforating suture). Technique Step 1: anterior vitrectomy (with the help of endoscopy for the vitrectomy in the posterior chamber). Step 2: Viscoelastic filling of the anterior and posterior chambers. Step 3: Endoscopic location of the ciliary sulcus, locating of the pupillary border, posterior iris, ciliary crown and sulcus. Step 4: Transcilioscleral perforation. Then, we perform the external scleral sutures with or without scleral flap. Thanks to the intraocular endoscopic control we are sure of the exact position of the ciliary site of perforation (100%). COMBINED ENDOSCOPIC PROCEDURES DURING PHACOEMULSIFICATION Endoscopy-assisted Combined Glaucoma Cataract Surgery (Figs 47.6 and 7) During phacoemulsification, the endoscopy is useful in performing endoscopic cyclophotocoagulation (ECP) or endoscopic internal trabeculectomy (EIT). Instead of the standard ab-externo trabeculectomy, the ports are the same for endoscopy and phacoemulsification, corneal or corneoscleral.

Fig. 47.6: Endoscopic cyclophotocoagulation (ECP): Anterior approach for laser-cyclodestruction . The target tissue for an ab-interno endoscopic photocoagulation is the pigmented epithelium. Precise endoscopic control allows qualitative and quantitative actions

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Fig. 47.7: Endoscopic internal trabeculectomy (EIT): Removing of the trabecular meshwork with a special aspirating trabeculectome (according to Leon). Ab-interno endoscopic approach combined to phacoemulsification. ( Leon’s trabeculectome with incorporated aspiration)

Fig. 47.8: Endoscopic view of the pars plana route, here too anterior on the posterior border of the ciliary crown (hemorrhage)

For ECP, the wavelength of the laser beam for destruction of the ciliary processes in the iridociliary angle is either 532 nm (KTP) or 488-514 nm(Argon) or 810 nm (semiconductor). For EIT, we have a special cannula with a roughed tip for removing the trabecular meshwork in the irido corneal angle. In the two procedures, the endoscopy allows to control the tips of the laser beam or of the cannula at the bottom of the angles— it is a complete endoscopic goniosurgery. In the whole cases we perform at first phacoemulsification, then for ECP procedure the cyclophotocoagulation of the ciliary processes and at last the PC-IOL implantation, whereas for EIT we perform the posterior implantation before removing the trabecular meshwork.

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Endoscopy-assisted Vitrectomy for Complicated Phacoemulsification (Fig. 47.8) The endoscopy can be performed during vitrectomy for the managements of: • Dislocated PC-IOls • The vitreous consequences of a large capsular rupture • Severe posterior capsular opacification witout possibility of pupillary dilatation • Or for removing of an intravitreal hemorrhage • Or repairing a pseudophakic retinal detachment. For posterior endoscopy the standard vitrectomy technique is utilized with three sclerotomies. For example for a right eye the inferotemporal port is used for the cannula of irrigation,the superotemporal for the vitreotome (right handed) and the temporal for the endoscope (left handed). It is possible to change hands during the same procedure.The length of the scleral port for the endoscope is standard thanks to the thin overall diameter of the endoscopic probe (20 G). We do not use the light pipe because the endoillumination is already provided by the endoscopic light.The endoscope is introduced with its light off—we put the light on only when the endoscopic probe is in the vitreous cavity. The whole images coming from the operating microscope or from the endoscope are directly seen through the binoculars of the operating microscope. REFERENCES 1. Boscher CD, Lebuisson DA, Lean JS: Vitrectomy with endoscopy for management of retained lens fragments and/or posteriorly dislocated IOL. Graefe’s Arch Clin Exp Ophthalmol 236:115, 1998. 2. Danilov AV: Flexibles microendoscopes—Ophthalmoendoscopic techniques and case reports. Arch Ophthalmol 108:956-57, 1990. 3. Fisher Y, Slakter JS: A disposable ophthalmic endoscopic system. Arch Ophthalmol 112:984-86, 1994. 4. Jacobi PC, Dietlein CS, Krieglstein GK: Microendoscopic trabecular surgery in glaucoma management. Ophthalmology 106:538-44 ,1999. 5. Joos K, Alward WL, Folberg R: Experimental endoscopic goniotomy—a potential treatment for primary infantile glaucoma . Ophthalmology 100:1066-70, 1993. Koch F, Spitnas M: Videoendoscopic vitreous surgery. Ophthalmol Surg 2:71-78, 1990. 6. Leon C, Leon J: Microendoscopie appliquée à l’implantation posterieure in Implants et Implantation posterieure. Paris DGDL 255-58, 1986. 7. Leon C, Leon J: Microendoscopic ocular surgery—a new intraoperative diagnostic and therapeutic strategy: Preliminary results in cataract and glaucoma surgery. AmJ Cataract Refract Surg 17: 568-76, 1991. 8. Leon C, Leon J: Endoscopic photocoagulation—a new way for the endocular laser Lasers Lights Ophthalmol 34:209-12, 1992. 9. Leon C, Leon J, Aron-Rosa D: Endoscopy under operating microscope—a new device. Surgical Endoscopy 9:79-81, 1995. 10. Uram M: Laser endoscope helps management phakic, pseudophakic glaucomas. Ocul Surg News 12:1237, 1994.

PHACOEMULSIFICATION: THE EYE CAMP WAY

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Keiki R Mehta Kirit K Mody Ranjit H Maniar Cyres K Mehta Akhil Bharadwaj

Phacoemulsification: The Eye Camp Way

48

THE CONCEPT OF “EYE CAMPS” Eye Camp surgery was conceived in the early 1900s as a technique of taking surgery to the inner remote areas of the country not served by any basic means of transport. It was initially designed to function as the only source of eye care in a population which was not served by any ophthalmic service. The surgical team, after traveling into the interior, would need to stay, or hold “camp” at the site. Minimal equipment, easily transportable, would be utilized, consonant with the tenets of functional basic surgery with adequate sterility. COMPROMISES IN AN EYE CAMP An eye camp, by its very nature, is a collection of compromises. There are compromises in diagnostic equipment and as a corollary, in diagnosis, in patient evaluation and assessment. Since literally an entire hospital complex needs to be carved out of a set of rooms or a building which had never been designed for this usage, compromises in theater preparation, equipment, nursing personnel, have become inevitable. However where the compromises must end are in the quality of surgery, in the maintenance of absolute sterility, presurgical, during, and postsurgery, and in the type of postoperative care and postoperative assessment. Finally, maximum emphasis should be paid on prescribing as accurate a refraction as possible and the delivery of precisely correct spectacles, so that the final visual efficiency is exceptional. After all, from the patient’s point of view, a good eye camp is one which gives excellent visual acuity to the maximum number of patients in the minimum amount of time with preferably none or minimal complications.

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ORGANIZATION OF A PHACO EYE CAMP—HOW DOES ONE PROCEED A regular ECCE eye camp is very labor intensive and involves a fair bit of planning and implementation. On the other hand, a phaco camp is far easier. By and large the biggest advantage is that one need not arrange for all the cots, for the overnight accommodation toilet facilities and food for all the huge numbers. The usual arrangement is to prepare for 50 beds, with a rotation of the patients every hour. Food arrangements can be limited to tea and biscuits and light snacks. It makes sense to arrange for a transportation for the patients who are living in a 15 mile radius. They are bussed down, operated and a few hours later, dropped back to their village. Thus the only residential requirements are for the doctors and the eye camp personnel. This cuts the costing down very considerably. THE OPERATING ROOM SET-UP The ideal is to have three sets of operating facilities. Each facility to be completely self-contained. Each facility should have two tables. The minimum comfortable size for each facility is 25 feet by 15 feet. Anything smaller makes it too cramped for comfort. Fortunately this is the standard size of classrooms in India so that the size works well. Each facility has two additional smaller rooms for • Preparation of the instruments and a single small high speed portable (8 minute) autoclave (speed clave) • Patient preparation room, where the face is washed out with hot water and soap and antibiotic and dilating drops are put prior surgery. Each facility has two phacoemulsifier, (Experience in India has shown that the Alcon Universal, the Allergan Opsys, Storz Protégé, Opticon P4000 and Pulsar and the Indian made Appasamy unit are the most popular and all seem to work well and are very portable and economical to maintain with full reusable tubing’s. THE SURGEONS Regrettably the concept of success in an eye camp surgery was always devoted to the number of surgery done and not to the quality of results which would be obtained at the end of the surgery. Except for about a handful of high quality, mass-scale surgery institutions, the results of the other institutions have results ranging from poor to pathetic. Much needs to be done to improve them. It has also been a concept that Eye Camp surgery meant a training ground for novices learning surgery or for those who went to polish up their surgical skills. Nothing could be further from the truth, Eye Camp surgery is essentially done by the best surgeons available who can do a high quality work, hour by hour with consistently good results. It is best to have two tables together in one room as it makes it easier for a 5-member team of ward boys to place the patients on the table and to escort them off later and to clean the instruments.

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The other advantage of putting two surgeons together is that it is much more comfortable to have someone to talk to. Usually a very trained surgeon is coupled with one who may be equally good but lacks the ability to do sustained rapid surgery. STERILIZATION FACILITIES India has been plagued with camp after camp which has had massive infections due to an inadequate emphasis on sterility. I would once again emphasize that where mass work needs to be done, the emphasis on sterility has to be even more than that which would normally be used in a base hospital. All instruments need to be washed in boiled sterile water (a major outbreak of infection in the north India had taken place just 4 years ago due to washing the instruments in feces contaminated water. Though they were subsequently boiled, the boiling was inadequate to control the contamination. 362 eyes were lost due to pyocyaneous infection). The days of keeping boilers, and placing instruments in kitchen utensils should now be delegated to the dark ages. Portable flash sterilizers ( 8 minute cycle) are now freely available and are very effective. Virtually all India now has electricity and where it is not available, a brace of 5kVA portable Honda Generators work very well. PERSONNEL IN THE THEATER The ideal theater room composition should be a scrub nurse, who surgically assists the surgeon, and an assistant to her who remains unsterile and who rotates between two tables. The scrub nurse, does not change her gown but only her gloves with every case. For instrument preparation it has been found best to use two separate teams. Each team has a nurse and a ward boy. Once the case is finished, she will wash the instruments, place them into the sterilizing box and then put it herself into the autoclave. The ward boy keeps a look out for the sterilizing cycle and once it is complete will take the instruments out of the sterilizer and with the help of the nurse arrange them on a table and keep them ready for the next case. The instrument nurse then washes up again, dons a fresh set of gloves and commences preparing the table filling the syringes which are to be kept sterile on the instrument trolley. This technique has a big advantage that the instrument nurse knows all about the instruments, where they are placed and their functional status. The instruments do not get lost or broken. In addition it makes for far faster and, more efficient application. POWER GENERATORS In India, as with many developing countries, power outage is not uncommon. It is important when the eye camp is planned that one should compensate for this

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Fig. 48.1: Patients at computerized admission center

Fig. 48.2: Patient brought from mobile eye camp

PHACOEMULSIFICATION: THE EYE CAMP WAY

Fig. 48.3: Routine preoperative check-up

Fig. 48.4: Temporary wards in eye camp—each with 500 beds

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Fig. 48.5: Autoclave room

Fig. 48.6: Patients going to operation room in a row chanting hymns

PHACOEMULSIFICATION: THE EYE CAMP WAY

Fig. 48.7: A-scan recording

Fig. 48.8: Postoperative ward round

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Fig. 48.9: Postoperative ward round

Fig. 48.10: Patients having breakfast

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Fig. 48.11: Free spectacles distribution to postoperative patients

Fig. 48.12: Computerized pharmacy department

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Fig. 48.13: Patients ready to go back home, seeing the world better!

Fig. 48.14: Patients transferred from theatre to ward by stretcher

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Figs 48.15 and 16: General views of ward

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Fig. 48.17: Patients prepared for surgery, drapped and ready, so surgeon, microscope and phaco unit can roll to site

Fig. 48.18: Surgeons preparing for final surgery

PHACOEMULSIFICATION: THE EYE CAMP WAY

Fig. 48.19: Surgeons preparing for final surgery

Fig. 48.20: Final rounds before being sent home

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Fig. 48.21: The final departure

problem. Though it would be nice to have automatic switch-over power systems where the load is taken temporarily on batteries and then automatically shifted to the generated supply, it is a very costly system which is rarely used. Instead small power generators (Honda or Suzuki 5kVA portable generators running off kerosene or diesel) are utilized, adequate to run the theater lamps, general lighting and power the instrument including the phacoemulsifier and support systems. It is important that the wiring should be so organized that all that needs to be done, at a time of a power failure, is to turn over the switch and start the generator. The load on the generator should never exceed 75% of its rated output to prevent overload and tripping. The generators, which are usually run off petrol, kerosene or diesel, all have a few common features. They are all noisy, smelly and temperamental. Hence they need to be placed in a room with good ventilation, and isolated so that the sound and smell does not reach in the theater complex. They should be serviced regularly, and have personnel trained to start and run the units. PREOPERATIVE CARE AND EVALUATION Preoperative check-up consists of a routine evaluation done to exclude fever, severe cough, open sores around face. Routine urine checkup to exclude diabetes and a blood pressure check to exclude hypertension. A routine check of the chest should done to exclude any gross cause for exclusion.

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Since most of the cases are to be done with topical anesthesia, starving is unnecessary. The patients are told to have their meals as per their normal routine. Patients are called in shifts of two hours. Experience has shown that a moderately competent phaco surgeon can do, comfortably, without overextending himself, 6 cases per hour, and can work comfortably a four hour shift, when a mandatory one hour rest period is imposed. With 6 surgeons per shift, it works out to be about 145 cases approximately per four hour shift ( 24 cases per surgeon approx). Thus for a 8 hour shift per day, about 300 to 325 cases are completed which is the safe average. In practice, once the team settles down and gets into swing it is a bit faster. DURING SURGERY Semiscleral, corneal tunneled incisions are the best since a 5.00 mm phaco PMMA lens is usually implanted. Consistently rapid predictable surgery with minimal surgical steps should be planned for. No suturing required in most cases, though in an occasional use a single infinity stitch may be applied. Normally, hardly 2 to 4% of cases need a single stitch. However the surgeons must be aware that what we are looking for is exceptional results. Even in the event of vitreous break, thanks to the rhexis a PC IOL can still be safety implanted in the sulcus. Fortunately with phaco the risk of late postoperative infection is severely minimized as the eye is for practical purposes sealed following surgery. Hence there is no restriction placed on the patients postoperatively. Postoperative Advantages • Rapid rehabilitation, hence sleeping on floor mats under unhygienic conditions obviated. • Negligible astigmatism induced, hence the spectacles prescribed on the 7th day, are usually stable. • Chances of late complications like sutures unraveling, accidental wound dehiscence or secondary infection. are very remote • Preoperative medical requirements—negligible except for eyedrops. • Resumption of activity virtually immediately, with rural daily chores commenced the very next day. • Preoperative satisfaction high, hence greater village support for future eye camps, better support from health workers and local medical support teams. Better governmental support translates into logistical and financial assistance. FINANCIAL IMPLICATIONS OF A PHACO EYE CAMP VS ROUTINE ECCE EYE CAMP Let us assess the financial implications of an phaco eye camp, its visual results, complications and, most important of all, the financial implications, as compared to a routine ECCE eye camp, held prior at the same venue. It is often considered

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that a phaco eye camp would prove costlier. Nothing is further from the truth. Tables 48.1 to 10 show the pertinent data in a small eye camp done consecutively, in the same area 4 months apart. Phaco has proven to be very economical. In a county like India and for that matter any Third World or underdeveloped country, where there is acute financial stringency, the ability to do more cases for much less is a very important factor. Table 48.1: Phaco camp at Dhappandar village: Maharashtra • A controlled study utilizing a minimal team of 3 refractionists, 8 nursing technicians, and a single surgeon. • Total cases examined preoperative = 1865 • Refraction done on = 845 cases • Cataracts detected = 122 of which 107 elected for surgery. • Two surgical days, session 8.00 AM to 5 PM with breakfast, lunch and tea breaks. Most cases (84/107 = 91.3%) under topical.

Advantages of Phaco over ECCE as an Eye Camp Alternative The greatest advantage of phacoemulsification is the virtually negligible quantities of astigmatism it produces even if a 5.00 mm PC IOL is inserted via a sclerocorneal incision and tunnel. ECCE despite our best efforts has proven infructuous and has, in simple words proven to be inadequate to the task in hand. The other very big advantage is obviously the immediate rehabilitation with virtually negligible postoperative late complications (almost 17% with ECCE). And finally, it is much cheaper to do phaco as compared to ECCE. Final Analysis Phaco is literally 10 times cheaper than ECCE. PROBLEMS OF A PHACO EYE CAMP • Phaco instrument needs a stable power supply. Fortunately the Honda generators are available nowadays which function well. • Use of a good stereopticon microscope with adequate depth of field is essential. • Need of UPS (uninterrupted power supply on all phaco machines and on the A scan units • Need for a miniflash autoclaves since phaco probes cannot be boiled. • Well-trained phaco team to permit rapid turn-around of cases. • Well-trained phaco surgeon with experience in handling hard cataracts and managing complications HOW GOOD IS INDIA’S ATTEMPT AT CONTROL OF BLINDNESS FOLLOWING CATARACT SURGERY • The results from cataract surgery, in being able to achieve adequate vision in eye camps is so poor that one is constrained to say that while cataracts

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Table 48.2: Assessment of cataracts in phaco eye camp

• • • • •

Type

No

Hypermature Mature Virtually mature Postsubcapsular Indeterminate

22 71 14 6 9

TOTAL

107

Table 48.3: Visual acuity : following phaco camp

• • •

Acuity

3rd day No

PO (percentage)

7th day No

PO (percentage)

6/6-6/9 6/12-6/18 6/24-6/36

82 19 6

76.6 17.7 5.7

93 10 4

86.9 9.3 3.8

Table 48.4: Surgical complications: phaco eye camp (n = 107) • • • • • • • • •

Conjunctival bleed 8 Capsular break 3 PC IOL implanted 2 AC IOL implanted 1 Phaco iris erosion 9 Inadequate tunnel 6 Postoperative corneal striae > 2+ 4 IOL edge in pupil 4 Shallow chamber 5

7.4% 2.8% 1.8% 0.9% 8.4% 5.6% 3.7% 3.7% 4.7%

Table 48.5: Raw costing of a phaco eye camp • The costing is in Indian rupees. • • • •

Conversion rate at present US $ 1.00 UK Pound 1.00 German Mark 1.00 Swiss Franc 1.00

is = = = =

39.60 Rupees 74.5 Rupees 22.85 Rupees 27.80 Rupees

are the highest cause of blindness in India, the second highest cause of blindness after cataracts, is surprisingly, cataract surgery. • The success rates following cataracts surgery range from 30 to 50 percent success. The invariable cause of failure is inadequate visual correction, more often than not, due to excessive quantities of astigmatism. • The second biggest cause for failure is postoperative complications which were untended primarily, subsequently not noticed, improperly managed, or simply ignored (usually the latter).

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Table 48.6: Surgical expenses: phaco vs ECCE Item

No

Phaco (Cost in Rs.)

No

ECCE (Cost in Rs.)

Xylocaine (2%) Xylocaine (4%) Hylase Sutures — 8/0 — 10/0 — Viscoelastic Carpinol Inj.

2 14 -

20 140 -

25 4 13

245 40 208

4 52 8

600 2500 96

106 112 68 92

13250 16800 3264 1104

SUBTOTAL

3356

34911

Table 48.7: Surgical expenses: phaco vs ECCE Item

No

Phaco Cost

No

ECCE Cost

•Betadine soln •Disp syringes •Inj garamycin •Ringer lactate •Drip sets •Phaco needle

10 188 22 42 8 1

350 940 286 1470 200 2250

10 226 8 14 8 __

350 1130 104 490 200 __

SUBTOTAL SUBTOTAL (Prev slide)

__ 3356

3246

__

2274 34911

FINAL TOTAL

8852

37185

- 82.70

347.50

PER PATIENT (107)

Analysis It would seem obvious from the statistics that the sight restoration rate (Table 48.11) even with as broad a criteria as 6/60 ranges hardly from 28 to 39 percent. In essence virtually 7 out of 10 do not regain useful vision, certainly not anything to be proud about. POOR OUTCOMES IN CATARACT SURGERY Analysis of 4168 cataract surgeries meticulously followed showed • 37.8% good outcome—6/18 or better • 45.6% borderline outcome—6/24-6/60 • 16.6% poor outcome—<6/60 Limberg: Vaidyanathan, 1998 Where are the Answers? The obvious answer is • Improve drastically the quality and level of surgery. The results show that it is mandatory.

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Table 48.8: Nonsurgical expenses: phaco vs ECCE • Sleeping Arrangements Hire..Cot + mattress+2 sheets+pillow Transport Cot/mattresses pillow to site Cooking utensils/wood etc. (2 trucks)

Rs 3680 Rs. 8832 Rs. 4000

• Food Expenses 6 Tea, 6 Lunch/6 Dinners Crockery @Rs. 27.50 per meal (US $0.68 ) and Rs. 3.25 for tea with biscuits (US $0.08)

Rs. 17572

• Washing facility Soap/towel etc.

Rs. 1800

Table 48.9: Nonsurgical expenses: phaco vs ECCE • Lavatory Expenses Special lavatory facilities, dugout, maintain fill and re plant

Rs. 3800

• Electricity/Kerosene expenses Hire, transport of lamps, petromax bulbs plus generator run for night meals

Rs. 4000

•

Miscellaneous:

Water provision, ancillary expenses, running ancillary medical services, drugs etc. Rs. 5000

TOTAL EXPENSES (4 days)

Rs. 48680

Per patient cost = Rs. 455/

Table 48.10: Financial analysis: phaco vs ECCE Expenses

Phaco

ECCE

Rs. 8,852 Rs. 82.70

Rs. 37,185 Rs. 347.50}

nil nil

Rs. 48,680 Rs. 455}

TOTAL EXPENSES

Rs. 8,852

Rs. 85,865

PER PATIENT EXPENSES

Rs. 82.50

Rs. 802.5

Surgical Expenses Basic expenses {Per patient (107) Residential Expenses Expenses for total 4 days ) {Per patient cost =

• Prescribe perfect postoperative glasses. The heinous crime of giving standard “plus lens” should be discontinued forthwith if one is not to convert the “cataract blind” to “spectacle blind”. • Try and decrease astigmatism as far as possible. It will not only permit better postoperative vision but will need to have fewer refractive changes later. • Achieve a much higher level of accuracy in IOL power calculation . This also means far more accurate keratometry. • Common sense indicates that it is now time that ECCE gave way to phaco.

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Table 48.11: Sight restoration rate in two units in Ludhiana Punjab Preoperative visual acuity Visual acuity Eye camps Ludhiana (persons) (‘95) (‘84-’93)

Ludhiana (‘94)

Postoperative visual acuity Eye camps Ludhiana Ludhiana (‘95) (‘84-’93) (‘94)

6/6 - 6/18 <6/18 - 6/60 <6/60 - 3/60 <3/60 - PL

57 28 41 93

4,429 5,971 2,815 10,106

618 1,226 509 1,183

145 67 7 0

8,665 12,633 935 1,088

1,530 1,813 79 114

TOTAL

219

23,321

3,536

219

23,321

3,536

Sight restoration rate (pre-op<3/60 - post-op>3/60) 43% 39% 30% Sight restoration rate (pre-op<3/60 - post-op>6/60) 39% 35% 28% The proportion of cataract operations with a visual outcome less than 6/60, by place and type of surgery Short term (4-6 week follow-up)

total eyes

VA<6/60

All eyes

4168

16.7%

Why not Small Incision ECCE Rather than Phaco. Is it a Viable Option? There has been a strong trend in utilising the small incision techniques like the Blumenthal technique and the sandwich technique, or for splitting the nuclei with various instruments in an effort to do the entire surgery through a 6.00 to 7.00 mm incision. The methods seem so easy and the results are commented upon at all major meetings as being just short of extraordinary that it is not surprising that there has been a trend to shift from regular ECCE to small incision ECCE. It would solve the problem of astigmatism, and would, to some extent even sort out the problem of late complication of ECCE and would not, in a good majority even need to be sutured, or if sutured a single mattress suture may prove adequate. The problems however slowly came to light. Gross endothelial cell decompensation. In an eye camp held in the periphery of Maharashtra where the authorities called its a “phaco style” surgery, the follow-up after 6 months showed almost 18% had hazy vision due to corneal decompensative changes. Obviously, unless the surgeons were superbly trained and used excellent microscopes, as an eye camp surgery, small incision ECCE was a catastrophe. One of us ( KRM) spoke about it at the state conference and labeled it as the “endothelial holocaust“. Its bad to leave astigmatism, but to leave decompensated corneas is criminal. Endothelial Holocaust More corneas have been ruined from trying to do an inadequate non-phaco small incision cataract surgery then all the transgressions,till date, combined. Why the Endothelial Holocaust • The corneal dome has inadequate space for gymnastics.

PHACOEMULSIFICATION: THE EYE CAMP WAY

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• The perception of depth is often inadequate unless exceptional microscopes are used. • Multiple entry in and out of the eye will invariably lead to inadvertent corneal touch with grave results. • A panicky surgeon leads to a lost eye. Nothing panics a surgeon as much as an uncooperative lens in a small incision surgery. • Subsequent often flat chambers due to traumatized wound entries lead to a further exacerbation of the problem Unfortunately it is the occasional surgeon, who tries his hand at small incision ECCE and rather than learn phaco, decides here is a simpler, cheaper way . The only advice one can give him is “Take it easy. If you really want to do small nonphaco techniques, learn from a master or take up Phaco. But please let the cornea survive.” Let us not wage a war against the poor unsuspecting, endothelium Let there be peace. PHACO VS ECCE EYE CAMP: THE FINAL WORD Undoubtedly, phaco eye camps are the way to go. The only barrier is the surgeon, as he or she has to be trained in the specialty, and must have the confidence to do so. Considering the virtually complication free status of phaco surgery, and the cost, literally 10 times cheaper than ECCE with results which are superb as compared to ECCE, one would feel that it is only a question in time when all eye camps, hopefully, and mercifully will be conducted ONLY by the phaco way. FURTHER READING 1. Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989. 2. Mehta KR: Clear corneal phaco with injectable silicone IOL proc. All India Ophthl Soc Proc (Mumbai) 1995. 3. Mehta KR: Mehta tangential chop (MTC) technique for phacoemulsification. All India Ophthl Soc Proc (Chandigarh) 1996. 4. Mehta KR: Combined astigmatic annular keratotomy and phaco—a corneal topographic analytical techniques. All India Ophthl Soc Proc (Chandigarh) 1996. 5. Mehta KR: Lollipop phaco cleavage—a new technique for hard cataracts. All India Ophthl Soc Proc (Bangalore) 1991. 6. Mehta KR: Phaco with flexible IOL—is it a step forward. All India Ophthl Soc Proc (Bangalore) 1991. 7. Mehta KR: Comparison of centration stability and capsular response to AcrySoft and silicone S130 lenses. All India Ophthl Soc Proc, 1998. 8. Mehta KR: Teaching standards in phacoemulsification—how realistic are they? All India Ophthl Soc Proc, 1998. 9. Mehta KR: Use of intracameral yellow (Kodak Wratten 59 Filter) fibreoptic light source for phacoemulsification in dense corneal opacities prior corneal transplantation. All India Ophthl Soc Proc, 1998. 10. Mehta KR: The tripod posterior chamber flexible acrylic implant—the answer to better stability.APIIA Conference, 1997. 11. Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997.

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12. Mehta KR: Astigmatic control using the new curved laminating keratotomy technique. APIIA Conference, 1997. 13. Mehta KR: Newer techniques for eye camp safe phaco techniques. APIIA Conference, 1997. 14. Mehta KR: The tripod posterior chamber foldable acrylic lens. Proc of SAARC Conference, Nepal, 1994. 15. Mehta KR: Phacoemulsification, the “roller-flip” way for suprahard cataracts—it works great. Proc of SAARC Conference, Nepal, 1994. 16. Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994. 17. Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994. 18. Mehta KR: Methylcellulose induced sterile endophthalmitis following phacoemulsification. Proc of SAARC Conference, Nepal, 1994. 19. Mehta KR: Double intraocular lens implantation for high ametropia and for correction of inadvertant remnant ametropia. Proc of SAARC Conference, Nepal, 1994. 20. Mehta KR: Comparison of scleral vs transiridial corneal suspended vs iridial suturing of PC IOL implants with inadequate capsular support. Proc of SAARC Conference, Nepal, 1994. 21. Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

INDEX

529

Index

A

C

Acrylic foldable IOL 268 explantation 277 implantation 269 two models 269 MA30BA 269 MA60BM 269 Agarwal chopper 83 Anesthesia 490 technique 187 Anterior capsulorrhexis 103 Anterior chamber managing the vitreous in 251 Aphakic eyes IOL scleral fixation in 422 indication for 423 Aspiration 246 basic parameters for 247 basic surgical principles 248 ideal circumstances for 248 pumps 22 system 21 Astigmatism excimer laser correction of 349 phacoemulsification in 344 surgical technique 350 Auto-tuning 34

B

Bausch and Lomb “Millennium” machine Brunescent and opalescent cataracts 302 anesthesia for 302 incision placement 303 surgical techniques 304 deshelling 304 pizza flop 306 saddle-hump 308 tangential chopping 310 vertical ‘Hubbing’ 311

44

Capsular bag 290 Capsular bag hyperdistention 101 Capsular cleaning 148 posterior capsulorrhexis 148 Capsular contraction syndrome 98 Capsular ring 385 Capsulorrhexis 94, 103, 178, 193, 238, 240, 382 advanced techniques 103 in special cases 109 physics of 103 principles 103 ripping technique 104 shearing technique 104 with ripping 105 with shearing 104 Capsulotomy 219 anterior 232 radiofrequency endodiathermy for 219 Cataracts suprahard 299 evaluation 299 management 299 phacoemulsification of 299 brunescent 299 opalescent 300 Cataract extraction 326 Cataract extraction and lens implantation aspiration of residual cortex 168 implosion technique 161 lens implantation 168 phacoemulsification of lens contents 164 surgical approach 162 capsulorrhexis 163 hydrodissection 164 reconstitution of AC 163 three different techniques chop 168 divide and conquer 165 implosion method 166

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Cataract surgery 493 laser phaco 493 Cavitating microbubbles 45 history 45 Cavitation bubbles 47 Chronic obstructive pulmonary disease phacoemulsification in 388 oxygen therapy 389 Cionni endocapsular ring 173 Clear corneal cataract surgery 86 Clear corneal incisions 87, 88 advantages 87 controversies 87 rationale of 91 strength of 88 techniques 89 new blade technologies 90 Cobra tip 34 Combined endoscopic procedures 504 Common phaco handpiece 19 mechanism of action 20 terminologies 19 actual 20 constant vs pulse 19 effective 20 frequency 19 linear vs panel 19 maximum 20 phaco power 19 stroke length 19 Compression of the inflow tubing 36 Continuous curvilinear capsulorrhexis (CCC) 94 advantages of 98 anatomy of lens capsule 94 complications of 98 instruments 95 posterior CCC 97 technique 95 terminology 94 two-staged CCC 96 Corneal astigmatism 91 topographic control of 91 Corneal endothelium evaluation of 365 importance 365 Corneal tunnel 86 Corneal tunnel incisions 88 classification of 88 Cortical aspiration tips for 221 Cortical washing 449

D

Diaphragm pump 24 advantages of 24

disadvantages of 25 Dropped nuclei 486 Drugs in phacoemulsification 453 alternate additives 459 antibiotics 458 antiinflammatory agents 459 antiseptic solutions 453 intraocular solutions 453 irrigating solutions 454 miotics Am 460 mydriatics 460 viscoelastic substances 458

E

Endomicroscopy 501 Endoscopic suture techniques 502 method 504 technique 504 Endoscopy 500 Endothelial cell analysis 376 areas 367 count 366 density 367 loss 367 why endothelial cell loss 369 protection 371 techniques in phacoemulsification 371 decrease fluid input with zero suction 371 Endothelial holocaust 526 Endothelial microscope 365 contact 366 non-contact 366 Epinucleus removal 147 Eye camps compromises in 507 concept of 507 financial implications of 521 organization of 508 operating room 508 personnel in the theater 509 power generators 509 sterilization facilities 509 surgeons 508 preoperative care and evaluation 520 problems of 522

F

FAVIT 486, 491 advantages 491 Fluidic balance 27 Foldable intraocular implants 253 Foldable IOL implantation 449 Foot pedal 28

INDEX G

Generic phacoemulsification machine Glaucoma 322 diagnosis of 322 in cataract patients 322 management of 322 uncontrolled glaucoma 326 Graefe section 86

H

32

High myopia 243 High-vacuum settings 34 Hydrodelamination 195 Hydrodelineation 383 decompression of the capsule bag 115 hydrofracture 116 Hydrodissection 136, 195, 220, 225, 234, 239,383 technique 112 Hydrodissection and hydrodelineation 180 Hyperproliferation 102

I

Incisions 178 capsulorrhexis 133 side port 132 temporal 132 Incision closure closing the self-sealing wound 153 suturing the wound 153 Incisional leakage 36 Initiation of capsulorrhexis 105 advantages of 108 difficulties rhexis escape 108 methods capsulostripsis 106 diathermy capsulotomy 106 forceps technique 106 needle technique 106 principles 107 Injection anesthesia 61 risks of 61 Innovative nucleotomy 204 Intracameral adrenaline 170 Intraocular lens implantation (IOL) general consideration 149 viscoelastic 149 wound sizing 150 implantation 150 instruments 150 technique 150 insertion 184 lens implant 150 Intraocular lens specifications 254

531

Intraocular lenses dislocated into the vitreous 479 a case report 480 diagnosis of dislocation 482 visual acuity 483 Intumescent cataract 97, 174 IOL material 99 role of 99 Iris hooks 171 protector ring 171 retractors 228 Irrigation 246 Irrigation system 21 Irrigation/aspiration 147

K

Kelman tip 34 Keyhole iridectomy 227 Kratz cannula 407 method of polishing the capsule Kuglein hook 233

407

L

Laser YAG: YLF 493 instrumentation 494 Sunita agarwal laser phaco probe photon 496 phakonit 451, 498 Lens acrylic 258 AcrySof 257 hydrogel 257 implantation 263 history of 263 Memory 257 Ridley 263 recent advances 266 subsequent modifications 264 Lens implantation tips for 222 Lens removal 37 control of flow 40 control of power 38 foot pedal “positions” 38 control of vacuum 40 principles of 37 chopping 37 sculpting 37 snapping 38 technique for soft nuclei 138

494

532

THE ART

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Limbal incision 64 clear corneal 65 advantages 65 evaluating limbal versus clear corneal 65 incision design 66 incision shape 66 Langerman hinge and Gills modification 67 posterior 64 scleral incisions 70 superolateral incisions 71 Limbus vs clear cornea 74 Agarwal karate chop technique 77 cortical washing 82 foldable IOL implantation 82 hydrodissection 79 incision 77 pad, S/C injections 83 pulse phaco 81 rhexis 78 stromal hydration 82 two halves 79 phaco chop technique 76 introduced by Dr Nagahara 76 Local anesthesia 51 agents 52 injectable 52 topical 52 alternative methods 55 peribulbar 56 retrobulbar 56 sub-Tenon’s 56 topical 56 mechanism of action 51 techniques 52 peribulbar injection 54 retrobulbar injection 53 Loop lenses 293 optical zones of 293

M

Magnetostrictive mechanism 32 Mature hard nucleus 236 Mature white cataract 237 Modified phacoemulsification in situ 204 Multiport phaco tip 471 a new teaching tool 476 advantages of 475 availability 477 design 474 function 474 functions of 472 problems with blockage of the bore 472 inadvertent capsular contact 472

N

Nagahara chopper 158 Nd: YAG laser 101 role of 101 Nuclei dense 182, 183 soft 181 Nucleus removal 139, 180, 220 combined glaucoma and cataract surgery 146 emulsification 140 enlargement of the pupil 145 small pupil 145 technique for hard nuclei 143 technique for medium hard nuclei 140

O

Operating room requirements and necessities 1 air-conditioning and ventilation autoclave 4 electrical power 3 footwear use 11 lighting 2 noise level 3 operating microscope 7 operating table 5 personnel 4 power generators 3 scrubbing facilities 4 surgical chair 6

P

Peribulbar anesthesia 131 Peristaltic 487 Peristaltic pump 22, 33 advantages of 22 disadvantages of 23 Petalloid phacoemulsification 209 technique 209 Phaco machines in use Alcon legacy 131 Allergan AMO prestige 131 Allergan AMO sovereign 131 tips and sleeves 132 Phaco needles 48 transient cavitation 48 Phaco slice and separate 154 method 155 hydrodissection 155 Phaco tip 17 phaco power settings 18 Phaco transducers 46 basics of 46

2

INDEX Phaco-trabeculectomy 327 Phacoemulsification 1, 223, 239, 240, 384, complications at various phases of 395 clear corneal incision 396 during capsulorrhexis 398 problem with side port incision 397 endoscopy-assisted 500 in difficult cases 223 in white cataracts 214 management 216 capsulotomy 217 surgical considerations 217 modern nucleofractis techniques 118 four-quadrant cracking 118 stop and chop 119 morphological classification 214 type A 214 type B 215 type C 215 prevention of complications 399 problems of the nucleus 402 problems with nucleofractis 402 rupture of the posterior capsule 400 with hydrodissection 399 preventive aspects 393 aspiration of excess fluid 395 checking the intraocular pressure 394 fresh air under the drapes 394 placement of the lid retractor 395 quadrantic cracking, chopping and stuffing technique 120 central debulking and pregrooving 120 cracking 124 epinucleus removal 128 preliminary steps 120 segment removal 124 reasons for 214 Phacoemulsification before trephination tripple procedure with 462 advantages 462 Phacoemulsification technique 196 Phacoendoscopy 501 Phacomachine 15, 29 auditory feedbacks cause 30 mode 30 sound 30 basic features irrigation handpiece 15 irrigation-aspiration handpiece 15 magnetorestrictive handpiece 17 ultrasonic handpiece 16 essential of 29

533

Phakonit 446 principle 447 technique 447 hydrodissection 448 incision 448 rhexis 448 terminology 447 Physical endothelial cell protection hema intracameral endothelial contact lens 373 design of the hema hood 374 insertion of the hood 374 material of the hema hood 374 phacoemulsification 375 preparation of the hood 374 removal of the hood 375 Physics of phaco 25 irrigation 26 pump flow 25 rise time 25 Piezoelectric effect 32 Plate lens accommodating 288 Chiron vision 4203 and C10 289 mini-loop 288 modified 288 STAAR surgical 404 288 Polishers diamond impregnated 408 ultrasound 408 vacuum capsule 408 Posterior capsular rupture 184, 249, 409 causes for 409 management 410 with hyaloid face rupture 411, 413 without hyaloid face rupture 410 recognition of 249 signs of 409 Posterior capsulorrhexis special techniques 110 diathermy capsulotomy 111 tryphan blue staining 110 Posterior capsulotomy 407 intraoperative primary 407 Posterior chamber IOL capture management of 415 surgical technique for 417 complications in the surgery 420 treatment of 417 types of 416 with posterior synechiae 416 without posterior synechiae 416 Posterior implantation 502 endoscopy of 502

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Postvitrectomy 173 Postvitrectomy patients 244 Preferred phacoemulsifier 189 Previously filtered eye bleb revision techniques external bleb revision 340 hypotony maculopathy 342 phacoemulsification in 329 postoperative considerations 337 preoperative considerations 332 special considerations 332 surgical approaches 331 Pseudoexfoliation 174 syndrome 240 technique 381 Pupil enlarging surgery 227 Pupil stretching devices 231 Pupil stretching techniques 231 Pupilloplasty 228 stretch 171, 314 technical tips 315

S

Scleral fixation 423, 428, 433, 436, 441, 443 complications in 443 corneal decompensation 444 cystoid macular edema 444 endophthalmitis 444 fixation of the root of the iris 444 glaucoma 443 hyphemas and vitreous hemorrhages 444 IOL tilt 443 retinal detachment 444 Flieringa ring in 428 incision in 433 limbal 434 tunnel 434 intraocular lenses adapted for 424 “J”-type 424 AcrySof lens 425 Durval’s IOL 424 with ring on the haptic 424 IOL placement in 436 monitoring of 436 positioning of 437 limbal incision suture 439 suture fixation 438 sutures used in 425 10-0 polypropylene 425 10-0 prolene 425 9-0 polypropylene 425 vitrectomy in 441 Scroll pump 33 Side port incisions 36

Silicone IOLs 256 two types of 256 one-piece plate design 256 three-piece open loop designs 256 Sinus fracture and intranuclear nucleotomy technique 211 Slit nucleotomy 213 Small pupil 170, 226 Small-incision cataract surgery 58 ocular anesthesia for 58 other methods 60 topical anesthesia 59 traditional methods 58 Snap and split phaco 154 Society of cataract and refractive surgery 49 Soft cataracts 84 Sphincterotomies 171 Stable intraocular environment 35 String of pearls 102 Stromal hydration 449 Subincisional cortex removal techniques for 250 bimanual technique 250 ice-cream scoop maneuver 250 Subluxated lens 172 Surge suppression system 9 Surgeon’s requirements during the procedure 33 Surgical design “Ocusystem” 36, 41 sophisticated foot pedals 41 sophisticated microprocessors 43 “Sovereign” machines 43 AMO “Diplomax” 43 Sutherland scissors 232

T

Tactile feedback 29 Topical anesthesia cataract surgery 84 Topical/intracameral anesthesia 61 advantages of 61 contraindications 61 Toric IOLs 257 Trabeculectomy instruments 146 technique 146 white cataracts 147 Transscleral needle pass 432 Traumatic cataract 242

U

Uveitis

V

172

Vacuum-based pumps 33 FAVIT technique 487 rotary vane 33

INDEX venturi 23, 33, 487 advantages of 24 disadvantages of 24 Vertical “hubbing” phacoemulsification 187, 200 indications 201 technique of 200 coring the nucleus 201 nuclear stabilization 201 pulse aspiration of the ring 201 snapping the periphery 201 Videoendoscopy 425

Viscoelastic 178 Viscoelastic removal instruments 152 technique 152 Viscohydrodissection 114 Vitrectomy 426, 488, 491, 506 endoscopy-assisted 506 surgical technique 426 two port 491 Vitrector 490 three port 490

535