Pseudophakic Monovision E-Book

Fuxiang Zhang

• Herausgeber: Thieme Medical Publishers
• Kategorie: Fachliteratur
• Sprache: Englisch

Veröffentlichungsjahr: 2019

Beschreibung

A state-of-the-art resource on successful management of intraocular lens monovision

Pseudophakic Monovision: A Clinical Guide by renowned ophthalmologic surgery experts Fuxiang Zhang, Alan Sugar, and Graham Barrett reflects decades of robust academic research, with comprehensive discussion of the pseudophakic lens. Pseudophakic monovision is frequently used as a strategy for presbyopia correction in cataract surgery patients, with high satisfaction rates. The authors address the advantages and drawbacks to this approach, with topics ranging from the optics and neurophysiology of monovision to preoperative vision testing and counseling. The book fills a gap in the literature on this essential yet relatively neglected topic.

In the current era of an ever-expanding array of intraocular lenses inserted in cataract surgery, monovision correction is emerging as an efficacious, far less expensive method for managing presbyopia than multifocal lenses. One eye is corrected for optimal distance vision and the other for optimal near vision, thereby avoiding both the expense of multifocal lenses and inconvenience of wearing glasses and/or contact lenses. Emerging adjustable IOLs address eye dominance issues, enabling patients to attain excellent distance acuity in one eye, then select the amount of myopia that works best in the second eye.

Key Features

• Guidelines on basic calculations, optics, and techniques
• Various practical considerations, such as patient selection, incorporating IOL monovision into practice, essential preoperative tests, nighttime driving, and limitations
• Optics, neurophysiology, and graphic illustrations enhance understanding of the basics of IOL monovision including mini, moderate, and full monovision, as well as the concept of the not-sharply focused-zone
• Ocular as well as systemic contraindications, and how to use extra tests to detect subtle contr

Leseprobe

Pseudophakic Monovision

A Clinical Guide

Fuxiang Zhang, MDMedical DirectorDownriver Optimeyes Supervision CenterSenior StaffDepartment of OphthalmologyHenry Ford Health SystemTaylor, Michigan

Alan Sugar, MDProfessorVice ChairOphthalmology and Visual SciencesKellogg Eye CenterUniversity of MichiganAnn Arbor, Michigan

Graham D. Barrett, MB, BCh, SAf, FRACO, FRACSClinical ProfessorThe University of Western AustraliaPerth, AustraliaConsultant Ophthalmic SurgeonLions Eye InstituteConsultant Ophthalmic SurgeonSir Charles Gardiner HospitalNedlands, Australia

49 illustrations

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Library of Congress Cataloging-in-Publication Data

Names: Zhang, Fuxiang, MD, author. | Sugar, Alan, author. |

Barrett, Graham, (Ophthalmologist), author.

Title: Pseudophakic monovision / Fuxiang Zhang, Alan Sugar, Graham Barrett.

Description: New York : Thieme, [2019] |

Identifiers: LCCN 2018005469 (print) | LCCN 2018006724 (ebook) | ISBN 9781626238947 (e-book) | ISBN 9781626238930 (print)

Subjects: | MESH: Lens Implantation, Intraocular | Visual Acuity–physiology | Presbyopia–surgery | Pseudophakia–surgery

Classification: LCC RE938.5 (ebook) | LCC RE938.5 (print) | NLM WW 260 | DDC 617.7/55–dc23

LC record available at https://lccn.loc.gov/2018005469

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ISBN 978-1-62623-893-0

Also available as an e-book:eISBN 978-1-62623-894-7

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Contents

Foreword

Acknowledgments

1 Introduction

2 Optics and Neurophysiology of Pseudophakic Monovision

3 Non-Pseudophakic Monovision

4 Pseudophakic Monovision

5 Ocular Comorbidities and Pseudophakic Monovision

6 Special Situations

7 Limitations of Pseudophakic Monovision

Index

Foreword

Innumerable presbyopes hoping to minimize spectacle wear employ monovision with contact lenses or leave one eye myopic following LASIK. Likewise, pseudophakic monovision is frequently used as a strategy for presbyopia correction among cataract surgical patients with high satisfaction rates. Recent annual American Society of Cataract and Refractive Surgery (ASCRS) Clinical Surveys suggest that this is a significantly more popular strategy than multifocal IOLs, despite the premium fees associated with the latter. With these facts in mind, it is striking how little print or podium education is devoted to pseudophakic monovision—particularly for cataract and refractive surgeons.

Pseudophakic Monovision: A Clinical Guide is a much-needed comprehensive review of this important, but often omitted, topic. Chief authors Fuxiang Zhang, Alan Sugar, and Graham Barrett are each an authority in this field who combine their vast clinical experience and passion for teaching into a very practical and scientific textbook. In addressing the advantages and drawbacks to this approach, they cover topics ranging from the optics and neurophysiology of monovision to preoperative testing and counseling.

As a topic, pseudophakic monofocal monovision will never have the glamour and sizzle of the next new presbyopia-correcting IOL. Yet, despite how much has been written and discussed about accommodating, multifocal, and extended depth-of-focus (EDOF) IOLs, there is a glaring paucity of clinical studies comparing outcomes and patient satisfaction with these expensive technologies to monofocal monovision. Indeed, ophthalmologists would often select monofocal monovision for their own cataract surgery, according to many informal surveys, in order to avoid compromising quality of vision, particularly at night.

The popularity of pseudophakic monovision is about to change. The FDA recently approved the first adjustable IOL—RxSight’s light adjustable IOL. I believe that adjustable IOL technology will disrupt the refractive IOL industry for several reasons. In addition to improving our surgical refractive accuracy, it will allow patients to try out different refractive targets postoperatively in the pseudophakic state, before deciding on their preference prior to the adjustment. Imagine if you could guarantee excellent distance acuity in one eye, and then let the patient test and choose the amount of myopia that works best for their second eye. The pseudophakic patient could even use a soft contact lens trial to experiment with different eye dominance and with different amounts of anisometropia. This would shift the bulk of refractive counseling from pre-op to post-op, and it could be delegated to an optometrist. Most importantly, it would spare patients the confusing and stressful process of deciding what refractive system or outcome they want preoperatively without any ability to try it out. Finally, the refractive IOL adjustment would command a patient premium for postoperative refractive services that are clearly separate from the cataract operation. For all of these reasons, I believe that adjustable IOLs will elevate the popularity of monofocal monovision to new heights.

Lacking industry marketing or sponsored education about monovision, refractive and cataract surgeons will welcome this timely and practical textbook about an essential but relatively neglected topic. It will become a valuable resource as we incorporate new adjustable and EDOF IOL technology into our practices.

David F. Chang, MD

Acknowledgments

This work would not have been possible without my two coauthors. I ran into my teacher and mentor, Alan Sugar, in Cincinnati in 2005 when we were sitting in a classroom for Alcon ReStor certification. We were wondering if the ReStor IOL would be any better than pseudophakic monovision from a patient satisfaction and spectacle independence perspective. Since then, we together started our IOL monovision and refractive cataract surgery research. He has been actively providing me with the protected academic time for all of my research works. I have learned so much from him, not only clinical research skills, but also how to make one’s work the highest quality possible. I have had very high respect for Graham Barrett for his leadership in the field of refractive cataract surgery. I truly appreciate his insight and contributions to this book in the last few years. I also want to thank him for his tips and pearls to sharpen my skills in astigmatism management and for sharing his outstanding IOL formulas. I am very fortunate to have these two ophthalmologist giants to work with and to learn from.

I would especially like to thank Warren Hill, David Chang, and Lisa Arbisser for their generous support for allowing me to use their special case reports of IOL monovision contraindications in this book. I am sincerely grateful for their decades-long generous grants of their expertise and advice for my refractive cataract surgery skills. I have learned a lot from them.

Paul Edwards, MD, Chairman of the Department of Ophthalmology at Henry Ford Health System, clearly sees the unique value of IOL monovision in the field of refractive cataract surgery. Without his consistent and strong support, my IOL monovision research projects as well as this book would be impossible. I am very grateful to all of those with whom I have had the pleasure to work at the department of ophthalmology, Henry Ford Health System, in the last 19 years. I would especially like to thank Bithika Kheterpal and Robert Levine, who provided their invaluable feedback from cataract surgeon perspectives before we finalized our last version of the manuscript. Harmonious professional work with my optometry colleagues at Henry Ford Optimeyes has provided me with very strong support for my practice.

My whole staff team at the Downriver Optimeyes Center deserves special thanks for their hard work and outstanding service for our patients and year-round refractive cataract surgery–oriented clinical research. I am especially indebted to the team leader, Lori Cooper, research assistant, Andrea Wood, and our former team members Melissa Collins, Lynn Carter, and Jessica Artico.

The Kellogg Eye Center of the University of Michigan is where I had my second round ofophthalmology residency training from 1994 to 1997. I am using this opportunity to express my gratitude to everyone who taught me and supported me throughout the whole residency training with the Michigan family. I am very thankful for the aspiring guidance, invaluably constructive criticism, and friendly advice during my 3 years there. I am extremely thankful to Paul Lichter, our then chairman, who set the role of model to be a professional, ethical, and caring physician and who was the first one to introduce me to the beauty of the contact lens–induced monovision concept. My deep appreciation goes to Dr. Terry Bergstrom, our then residency program director, who provided me extensive personal support and professional guidance throughout the whole residency. I would especially like to thank Dr. Jonathan Trobe, who taught me how to use a very meticulous and well-organized approach for patient care. I cannot thank Dr. Steve Archer enough for his teaching of optics during my residency. Dr. Archer also graciously reviewed the optical analysis of IOL monovision in Chapter 2 of this book and I am very grateful for this. Special thanks to my fellow residents at the Kellogg Eye Center, Jason Burgett, Stephen Fox, Andrew Hanzlik, Bithika Kheterpal, Michael Kipp, and Amy Neuhoff Robertson, for their inspiration and friendship.

Zhongshan Ophthalmic Center, Sun Yat-san University of Medical Science, Guan Zhou, China, is where I earned my masters degree of medical research in ophthalmic fields from 1985 to 1988. Special thanks go to my mentors, Dr. Eugene Chen, MD, and Professor Dezhen Wu, PhD. I am very thankful for what they taught me, the basic medical and clinical research skills.

The Ophthalmology Department, the School of Medicine, Southeast University, Nanjing, China, is where I received my medical school education and first ophthalmology residency training from 1977 to 1985. I am deeply indebted to the medical school where I learned medicine and became the first MD in my family. My special gratitude goes to the late Dr. Guofan Su and Dr. Qianjin Guan and other teachers and mentors who taught me all the basic ophthalmic knowledge and skills. It is a great pleasure and good fortune to keep a lifelong close relationship with many classmates, with whom I shared our 5-year unforgettable medical-student life.

Thieme is a great publisher to work with. The enthusiasm, trust, and support from the managing team are fantastic, especially from William Lamsback and Elizabeth Palumbo. Without that, it would not have been a seamless process.

Nobody has been more important to me in my professional as well as personal life than the members of my family. Most importantly, I want to sincerely thank my loving and supportive wife, Fenfen, and my two wonderful daughters, Carlen and Carol, and our son-in-law, Kiran, for their understanding and support. Thousands of hours were taken away from weekend and family holiday for my clinical research and in the pursuit of this book, which I deeply appreciate.

Fuxiang Zhang, MD

1 Introduction

AbstractPresbyopic patients spend money and time to have contact lens monovision or laser vision correction monovision. So why do we cataract surgeons not use intraocular lenses (IOLs) more often to create monovision? For a cataract patient with a desire for spectacle independence after surgery, there are different ways to create monovision. If it were like buying a car, where the prospective buyers can try different models before they make a choice, then IOL monovision might be favored by many more, if not the vast majority of patients, due to the quality of vision from monofocal lenses, low cost, convenience of back up of glasses if needed, and close to negligible downsides.Monovision as a method of prescribing optical aids was first proposed in 1958 by Richard West-smith. The first clinical report was from Fonda in 1966. The first known IOL monovision paper was published by Boerner and Thrasher in 1984. IOL monovision is now the most common surgical management of presbyopia for cataract patients. IOL monovision not only can meet patient needs for spectacle independence, but can also build up one’s surgical practice and lay a strong foundation for premium IOL refractive cataract surgery. Integrating IOL monovision into premium IOL practice is very helpful or even essential for successful premium refractive cataract surgery. Crossed IOL monovision can be used to rescue one’s outcome when the first eye refractive target is missed with accommodative and extended depth of focus IOLs.

Keywords: IOL monovision, pseudophakic monovision, refractive cataract surgery, premium IOL and IOL monovision, clinical outcome of IOL monovision, nighttime driving and monovision, depth perception and monovision, patient satisfaction and monovision, pseudophakic monovision book, IOL monovision book

1.1 Introduction

Monovision is a term used when one eye is intentionally corrected for far and the fellow eye for near. Monovision is a misnomer. It gives the impression of using one eye only or that the two eyes do not work together. The name itself potentially can be a barrier, preventing some patients from considering it as a presbyopia management modality. Blended vision may be a better term. When both eyes work together, monovision provides increased depth of focus but maintains good binocular vision with decreased spectacle independence.

1.2 Why This Book Was Written?

1.2.1 Killing Two Birds with One Stone

People who do not want to wear reading glasses, or cannot wear bifocals, may intentionally use monovision with contact lenses, or may spend thousands of dollars to have laser corneal refractive surgery correction with monovision. Many studies in the literature have demonstrated its validation. Why then do we not use intraocular lenses (IOLs) more often for monovision, one stone killing two birds, when we do cataract surgery? That is the rationale for IOL monovision.

1.2.2 One of the Most Popularly Used Modalities

Increasingly, premium IOLs have become available in the last two decades with the same goal of increasing spectacle independence after cataract surgery, and most of them do well with high patient satisfaction. IOL monovision, however, still stands out with quality of vision, easy adaptation, fewer complications, and less out-of-pocket cost for patients. Modest monovision continues to be an attractive presbyopic solution and, in our opinion, should be considered a “premium” solution. It requires expert surgery, lens selection, and the utilization of toric implants or corneal incisions to reduce astigmatism. From a surgeon’s perspective, myopic defocus is one of the two bases of refractive cataract surgery, as expressed in the pyramid scheme in Fig. 1.1. From a patient perspective, choosing the type of IOL is not like buying a car, where one can try different models and then pick the best. No one will argue that monovision is perfect, with compromises such as fine stereovision, but the truth is that in real life, the negative impact is minimal. (See the section “What Benefits Can IOL Monovision Bring to Your Practice?”)

Before we have an ideal accommodating IOL, IOL monovision is still one of the best choices, if not the best, in the management of presbyopia among the cataract population. IOL monovision was the number one modality for the management of presbyopia in cataract surgery according to the 2013 ASCRS clinical survey.1 What is more, the trend of choosing IOL monovision increased between 2013 and 2014.2

Fig. 1.1 The two main components of refractive cataract surgery. (Courtesy of Alcon Laboratories, Inc., Fort Worth, TX, USA, 2016 AAO Meeting in Chicago, IL.)

1.2.3 Residency Education

Most ophthalmology residencies in the United States and the rest of world do not provide formal training for monovision. IOL monovision may not be easy to adopt if one never intentionally has tried it, even though he or she might be a very experienced cataract surgeon. The questions we sometimes get are “How do you know who are good candidates and who are not?” “How much anisometropia should I target?” “What are the contraindications?” From our own learning curve in the practice of IOL monovision, we wished there was a book available which could have provided us some suggestions, pearls, and pitfalls so that we did not have to learn many lessons the hard way.

1.2.4 Making One’s Surgical Practice Prosperous

A surgeon who does a large proportion of pseudophakic monovision in cataract surgery for those who desire glasses independence can be expected to have a busy and happy, no-advertisement-needed, prosperous practice, mainly from word of mouth of satisfied patients.

The above are the four main reasons why this book was written. To our knowledge, this is the first book exclusively designated to address IOL monovision.

1.3 A Brief History of Monovision

Monovision as a method of prescribing optical aids was first proposed in 1958 by Richard Westsmith, MD, of San Mateo, California, for presbyopic monocular contact lens wearers.3 In his paper, he revealed that he had a contact lens of + 1.50 D for his own left eye for reading. He did not need any correction for distance with a vision of 20/20 in each eye. He was unable to tolerate a bifocal for his office work. With monocular contact lens monovision, Westsmith experienced “I have had the contact lens about a month now and I find that I am able to wear it comfortably all day and I have complete clarity of near vision. I am undisturbed by the slight blur in my left eye at distance. With the corneal lens in place, my vision in the left eye is 20/50. However, with both eyes I am able to read J1 at 18 inches. There is no trouble with the ophthalmoscope, retinoscope, or slit lamp.”

The first clinical report was from Fonda in 1966 with 13 cases of monovision corrected by spectacles and contact lenses.4 He also described himself as a monovision user. “I have been wearing a + 3.00 D reading addition before my right eye, and a + 1.50 D reading addition before my left eye for two years. I adjusted immediately to this difference, which does not affect my reading comfort regardless of the circumstances or duration of reading. I can wear a + 2.50 reading addition before one eye and no addition before the other. I have worn a + 2.50 D reading addition before both my dominant left eye and nondominant right eye on different occasions which was accepted equally well. I was conscious of the new correction for less than four hours. I never experienced diplopia, and evidenced fusion by the four-dot test and the Wirt stereo-quantitative test.”

The first known pseudophakic monovision paper was published by Boerner and Thrasher in 1984.5 In that study, among the 100 IOL monovision patients, the need to have bifocals after the surgery decreased 50%. And IOL monovision is now the most common surgical management of presbyopia for cataract patients.1,2

For the last half century, monovision has been increasingly used for presbyopia management with an impressive success rate. There are different ways to provide monovision: spectacles, contact lenses, refractive lasers, intraocular implants, etc. This book concentrates on the discussion of IOL monovision, or pseudophakic monovision, but at the same time, other methods will be briefly discussed, since most of the monovision studies in the literature were with contact lens and laser vision correction. IOL monovision is barely discussed in the literature considering how widely it is used in our profession.

1.4 What Benefits Can Pseudophakic Monovision Bring to Your Practice?

1.4.1 To Meet Patients’ Needs

We used to be satisfied with regular telegraphy and then telephones, but now we are happier with smart phones and the internet. Science and technology will continue to advance. Cataract surgery was simply a vision rehabilitation procedure a few decades ago, but it is not so any more. Just from a spectacle independence point of view, our clinical survey (all the 441 cataract patients’ 697 eyes in 2016) noted that 44% of our cataract patients would like to have some level of freedom from glasses and nearly one-fourth would like to have complete glasses independence. If financial factors were not considered, these percentages would be expected to be much higher.

1.4.2 To Build Up Practice

About 10 years ago, one of my junior staff members called me (F. Z.) at home. He was wondering why his practice was not as busy since he had joined our health system a few years earlier and he wanted me to give him advice in terms of what made my practice very busy while we were in the same geographic area. My answer was “Do your best to satisfy your patients and do IOL monovision.” Our own comparative prospective studies proved slightly better overall performance and satisfaction in IOL monovision than multifocal IOL patients.6,7 When compared with premium IOLs, IOL monovision has a few obvious advantages:

1. High patient satisfaction. As mentioned below, our 10-year IOL monovision review with a de-identified survey noted 97% satisfaction. Anecdotal experience of IOL monovision success from Bill Maloney, one of the IOL monovision pioneers, was 99%.8

2. Use of monofocal IOLs with high vision quality. Many fewer complaints and very low IOL explantation rate. Downside in real life is negligible.

3. Back up glasses are very handy when the need arises to have full binocular vision.

4. Less or no direct patient cost.

These advantages are significant and word of mouth is the most powerful advertisement in the community. If one’s surgical complications are also very low, then one can expect a busy practice.

Overall, IOL monovision clinical outcomes can be excellent if we master all the key steps. We did a de-identified survey of all of our IOL monovision patients over 10 years. All 5,660 charts of consecutive cataract surgical cases performed by F. Z. from January 2005 to December 2014 were reviewed (followed up to August 2015). Among 359 qualified cases, 194 were enrolled, 30 had died, 48 declined participation, and the remaining 87 could not be contacted with at least three phone calls. Among the 48 who declined participation, the vast majority did not have regular postoperative follow-up.

The mean age was 72.5 years. The subjects were 135 females (69.6%) and 59 males (30.4%). Mean follow-up was nearly 3 years (35 months). Mean distance vision without correction for the distance eye was 20/24.7 and mean near vision without correction for the near eye was 20/28.1. Mean anisometropia was 1.30 D.

To ensure accountability and reliability, it was clearly described in the introduction of the survey letter to each patient that the surgeon is not going to have access to the survey and thus to kindly provide honest opinion. All the original data of the survey were handled by a research assistant, and the statistics were then performed by an independent statistician. The four brief outcomes of the survey are shown as follows (Fig. 1.2, Fig. 1.3, Fig. 1.4, Fig. 1.5).

Fig. 1.2 Spectacle independence, glasses use. (The number in parentheses is the patient number.)