A PRACTICAL MANUAL OF Diabetic Retinopathy Management A01a.qxd 12/29/08 14:07 Page i A Practical Manual of Diabetic Retinopathy Management. P. H. Scanlon, C. P. Wilkinson, S. J. Aldington and D. R. Matthews © 2009 by Peter H. Scanlon, Charles P. Wilkinson, Stephen J. Aldington and David R. Matthews ISBN: 978-1-405-17035-2 A John Wiley & Sons, Ltd., Publication A PRACTICAL MANUAL OF Diabetic Retinopathy Management Peter H. Scanlon MD, MRCOphth, DCH, FRCP Consultant Ophthalmologist, Gloucestershire and Oxford Eye Units Lecturer, Harris Manchester College University of Oxford Oxford, UK Charles P. Wilkinson MD Chairman, Department of Ophthalmology, Greater Baltimore Medical Center Professor of Ophthalmology, Johns Hopkins University Baltimore, USA Stephen J. Aldington DMS, FBIPP Gloucestershire Education and Research Development Manager, Cheltenham, UK David R. Matthews MA (Oxon), DPhil, BM, BCh, FRCP Professor of Diabetic Medicine, University of Oxford Chairman, Oxford Centre for Diabetes, Endocrinology & Metabolism Oxford, UK A01a.qxd 12/29/08 14:07 Page iii This edition first published 2009, © 2009 by Peter H. Scanlon, Charles P. Wilkinson, Stephen J. Aldington and David R. Matthews Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientific, Technical and Medical business to form Wiley-Blackwell. 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No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom. Library of Congress Cataloging-in-Publication Data A practical manual of diabetic retinopathy management / Peter H. Scanlon . . . [et al.]. p. ; cm. Includes bibliographical references and index. ISBN 978-1-4051-7035-2 1. Diabetic retinopathy—Diagnosis—Handbooks, manuals, etc. 2. Diabetic retinopathy—Treatment—Handbooks, manuals, etc. I. Scanlon, Peter H. [DNLM: 1. Diabetic Retinopathy—diagnosis. 2. Diabetic Retinopathy—therapy. WK 835 P895 2009] RE661.D5P73 2009 617.7′35—dc22 2008026360 ISBN: 978-1-4051-7035-2 A catalogue record for this book is available from the British Library. Set in 9.25/11.5pt Minion by Graphicraft Limited, Hong Kong Printed and bound in Singapore by Fabulous Printers Pte Ltd. 1 2009 A01a.qxd 12/29/08 14:07 Page iv Contents Acknowledgements, vii Prologue, ix Peter H. Scanlon 1 Introduction, 1 Peter H. Scanlon 2 Diabetes, 17 David R. Matthews & Peter H. Scanlon 3 Lesions and classifications of diabetic retinopathy, 30 Peter H. Scanlon 4 Screening for diabetic retinopathy, 46 Peter H. Scanlon 5 Stage R0: the normal eye, 58 Stephen J. Aldington 6 Stage M1: maculopathy, 70 Peter H. Scanlon 7 Stage R1: mild non-proliferative diabetic retinopathy (background diabetic retinopathy), 99 Peter H. Scanlon 8 Stage R2: moderate and severe non-proliferative diabetic retinopathy (preproliferative diabetic retinopathy), 104 Peter H. Scanlon 9 Stage R3: proliferative diabetic retinopathy and advanced diabetic retinopathy, 109 Peter H. Scanlon 10 Stage R3 with M1: proliferative diabetic retinopathy with maculopathy, 133 Peter H. Scanlon 11 The stable treated eye, 137 Peter H. Scanlon v A01b.qxd 12/29/08 14:09 Page v 12 The surgical approach to the diabetic eye, 144 Charles P. Wilkinson 13 Pregnancy and the diabetic eye, 151 Peter H. Scanlon 14 Low vision and blindness from diabetic retinopathy, 160 Peter H. Scanlon 15 Future advances in the management of diabetic retinopathy, 171 Peter H. Scanlon 16 Other retinal conditions that are more frequent in diabetes, 178 Stephen J. Aldington & Peter H. Scanlon 17 Conditions with appearances similar to diabetic retinopathy, 194 Stephen J. Aldington & Peter H. Scanlon Glossary, 203 Index, 207 vi Contents A01b.qxd 12/29/08 14:09 Page vi I am grateful to my colleagues in Gloucestershire who have provided very useful examples of conditions that have enhanced the quality of this book and also provided some text where their knowledge was superior to my own. I am particularly grateful for the contributions from the following people: • Lisa Collins (Lead Optometrist) was of great assistance in the sections about ultrasound B scan and perimetry. • Rob Johnston (Consultant Ophthalmologist) for provid- ing examples from his patients and writing a paragraph on electronic patient records and ocular anaesthesia. • Quresh Mohammed (Consultant Ophthalmologist) for providing expertise and ocular coherence tomography (OCT) images of patients with diabetic retinopathy. • Susan Carter (Senior Optometrist) for writing a section on low vision rehabilitation. • Mark Histed (Gloucestershire Screening Programme Manager) for taking numerous photographs for the book and assisting in obtaining some of the old photographs from our archive files. • David Mordant (Research Fellow in Ophthalmology) and Professor Andrew McNaught (Consultant Ophthal- mologist) for writing a section on oximetry. • Nigel Kirkpatrick (Consultant Ophthalmologist) for allowing me to use examples of his patients. • Dr Janet Ropner (Consultant Haematologist, Gloucester- shire Royal Hospital) for providing some haematology images. • Jenny Sykes (researcher), Liz Dawes and Alex Purcell (Clinical Audit) for tirelessly working on the provision of background research, patient histories, patient con- sent forms and information in support of the writing of this book. I am grateful to Dr Bahram Jafar-Mohammadi from the Oxford Centre for Diabetes, Endocrinology and Metabolism for providing a case history of a patient with HNF-1α MODY and my brother Dr John Scanlon, a Consultant Paediatrician at Worcestershire Royal Hospital, for his advice on a paediatric case history. I am also grateful to Dr Brendan McDonald, Consultant Ocular Pathologist at the John Radcliffe Hospital in Oxford, for providing pathology images. I would like to acknowledge my appreciation of Martin Joyce (Consultant Ophthalmologist) who taught me in the early stages of my ophthalmology career and has pro- vided images for this book and Tim Hart (Consultant Ophthalmologist) who was a great support and encour- aged me to use one of the early digital fundus fluorescein cameras. I would like to acknowledge the support of the Gloucestershire Eye Therapy Trust, who generously pro- vided the first digital fundus fluorescein camera, the first screening cameras and the first OCT equipment for the Gloucestershire Eye Unit, which has enabled the depart- ment to be at the forefront of modern ophthalmic imaging. We thank the editors for their support. We are very grateful to all the patients who have allowed photographs of their eyes and some case histories to be included in this book. We are grateful to our wives and partners for their patience and understanding and I am particularly grateful to my wife Sally for her support. Peter H. Scanlon Acknowledgements vii A01c.qxd 12/29/08 14:09 Page vii THE SCOPE OF THE PROBLEM OF THE EPIDEMIC OF DIABETES In 1997, Amos1 estimated that 124 million people world- wide have diabetes, 97% non-insulin-dependent diabetes mellitus (NIDDM), and that by 2010 the total number with diabetes is projected to reach 221 million. The regions with the greatest potential increases are Asia and Africa, where diabetes rates could rise to 2 or 3 times those experienced in 1997. In 2000, Sorensen2 reported that the World Health Organization has recognized that there is a ‘global epi- demic of obesity’ and the prevalence of type 2 diabetes is rising in parallel. The International Diabetes Federation have estimated the prevalence of diabetes in 2003 in the 20–79 age groups and projected this to an estimate in 2025. This is shown in Fig. 1. North America Reports from the USA and Canada have shown the fol- lowing rises. 1 In 2000, Burrows3 reported that the number of native Americans and Alaska natives with diagnosed diabetes increased by 29% from 43,262 to 64,474 individuals between 1990 and 1997. By 1997, the prevalence was 5.4%, and the age-adjusted prevalence was 8.0%. 2 In 2000, Mokdad4,5 reported the results of the Beha- vioral Risk Factor Surveillance System in the USA 1990–98. The prevalence of diabetes rose from 4.9% in 1990 to 6.5% in 1998 and to 6.9% in 1999. The pre- valence of diabetes was highly correlated with the prevalence of obesity (r = 0.64, p < 0.001). 3 In 2001, Boyle6 estimated that the number of Americans with diagnosed diabetes is projected to increase 165%, from 11 million in 2000 (prevalence of 4.0%) to 29 million in 2050 (prevalence of 7.2%). 4 In 2007, Lipscombe7 reported the prevalence of diabetes in Ontario, Canada to have increased substan- tially during the past 10 years, and by 2005 to have already exceeded the global rate that was predicted for 2030. Using population-based data from the province of Ontario, Canada, age-adjusted and sex-adjusted dia- betes prevalence increased from 5.2% of the population in 1995 to 6.9% in 2000 and to 8.8% of the population in 2005. The UK Reports from the UK have shown the following rises. 1 In 2000, Ehtisham8 reported type 2 diabetes emerging in UK children. 2 In 2001, Farouhi9 constructed an epidemiological model by applying age-, sex-, and ethnic-specific prevalence rates to resident populations of England at national, regional and PCT level. The estimated pre- valence of total diabetes for all people in England was 4.41% in 2001 equating to 2.168 million people. Type 2 92.3% and type 1 7.7% (166,000 people). 3 In 2002, Feltbower10 reported an increasing incidence of type 1 diabetes in south Asians in Bradford. 4 In 2006, the latest data11 in England for people diag- nosed with diabetes have shown a national prevalence of diabetes of 3.35%. 5 In 2007, Evans12 reported that a diabetes clinical infor- mation system in Tayside, Scotland, showed a doubling in incidence and prevalence of type 2 diabetes between 1993 and 2004, with statistically significant increasing trends of 6.3 and 6.7% per year respectively. Worldwide reports 1 In 2000, Sidibe13 reported that the rise in complications of diabetes mellitus in Africa has gone hand in hand with the growing disease prevalence. 2 In 2001, Zimmet14 reviewed the global and societal implications of the diabetes epidemic. Prologue Peter H. Scanlon A01d.qxd 12/29/08 14:10 Page ix North America 2003 2025 23.02 36.18 7.9% 9.7% South and Central America 2003 2025 14.16 26.16 5.6% 7.2% Africa 2003 2025 7.07 15.04 2.4% 2.8% South-East Asia 2003 2025 39.3 81.57 5.6% 7.5% Western Pacific 2003 2025 43.02 75.76 3.1% 4.3% Europe 2003 2025 48.38 58.64 7.8% 9.1% Fig. 1 World map and table showing the International Diabetes Federation prevalence estimates of diabetes in 2003 and 2025 in 20–79 age group. Region Year Number with diabetes (millions) % of population with diabetes Africa 2003 7.07 2.4% 2025 15.04 2.8% Eastern Mediterranean and Middle East region 2003 19.24 7% 2025 39.41 8% Europe 2003 48.38 7.8% 2025 58.64 9.1% North America 2003 23.02 7.9% 2025 36.18 9.7% South and Central American region 2003 14.16 5.6% 2025 26.16 7.2% South-East Asian region 2003 39.3 5.6% 2025 81.57 7.5% Western Pacific region 2003 43.02 3.1% 2025 75.76 4.3% 3 In 2001, Aspray15 reported that the prevalence of dia- betes in sub-Saharan Africa varied from 1% of the rural population to 5.3% of the urban population. 4 In 2004, Wild16 reported the prevalence of diabetes for all age groups worldwide was estimated to be 2.8% in 2000 and 4.4% in 2030. The total number of people with diabetes is projected to rise from 171 million in 2000 to 366 million in 2030. x Prologue The prevalence of diabetes is higher in men than in women, but there are more women with diabetes than men. The urban population in developing countries is projected to double between 2000 and 2030. The most important demographic change to diabetes prevalence across the world appears to be the increase in the propor- tion of people over 65 years of age. These findings indicate that the ‘diabetes epidemic’ will A01d.qxd 12/29/08 14:10 Page x USA Ethiopia DR PDR China DR PDR 27.3% 7.8% Australia DR PDR 21.9% 2.1% UK DR PDR DR PDR type 1 45.7% type 1 3.7% type 2 25.3% type 2 0.5% 37.8% 1.7% DR PDR 40.3% 2.73% Fig. 2 World map and table showing the reported prevalence of diabetic retinopathy (DR) and proliferative DR. USA Prevalence of DR 40.3% Prevalence of proliferative DR 2.73% UK Prevalence of DR in type 1 45.7% Prevalence of proliferative DR in type 1 3.7% Prevalence of DR in type 2 25.3% Prevalence of proliferative DR in type 2 0.5% India Prevalence of DR 13. 4% Prevalence of proliferative DR 1.9% Ethiopia Prevalence of DR 37.8% Prevalence of proliferative DR 1.7% China Prevalence of DR 27.3% Prevalence of proliferative DR 7.8% Oman Prevalence of DR 14.4% Prevalence of proliferative DR 2.7% Australia Prevalence of DR 21.9% Prevalence of proliferative DR 2.1% Variations in screening methodology may explain some of these differences. Prologue xi continue even if levels of obesity remain constant. Given the increasing prevalence of obesity, it is likely that these figures provide an underestimate of future diabetes prevalence. In 2006 Cugati17 reported data from the Blue Moun- tains Eye Study (BMES) in Australia that examined 3654 residents (82.4% response) aged over 49 years in BMES I (1992–1994). Survivors (n = 2335) and newly eligible residents (n = 1174) were examined in BMES II (1997– 2000). Diabetes was defined by history or fasting plasma glucose ≥7.0 mmol/L. The overall diabetes prevalence increased from 7.8 to 9.9% (p = 0.002). THE PREVALENCE OF SIGHT- THREATENING DIABETIC RETINOPATHY WORLDWIDE See Fig. 2. A01d.qxd 12/29/08 14:10 Page xi