Textbook of Ophthalmology Textbook of Ophthalmology 5th Edition HV Nema Former Professor and Head Department of Ophthalmology Institute of Medical Sciences Banaras Hindu University Varanasi India Nitin Nema MS Dip NB Assistant Professor Department of Ophthalmology Sri Aurobindo Institute of Medical Sciences Indore India ® JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD. New Delhi • Ahmedabad • Bengaluru • Chennai Hyderabad • Kochi • Kolkata • Lucknow • Mumbai • Nagpur Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd B-3 EMCA House, 23/23B Ansari Road, Daryaganj, New Delhi 110 002 I ndia Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021, +91-11-23245672 Rel: +91-11-32558559 Fax: +91-11-23276490 +91-11-23245683 e-mail: [email protected], Visit our website: www.jaypeebrothers.com Branches 2/B, Akruti Society, Jodhpur Gam Road Satellite Ahmedabad 380 015, Phones: +91-79-26926233, Rel: +91-79-32988717 Fax: +91-79-26927094, e-mail: [email protected] 202 Batavia Chambers, 8 Kumara Krupa Road, Kumara Park East Bengaluru 560 001, Phones: +91-80-22285971, +91-80-22382956, 91-80-22372664 Rel: +91-80-32714073, Fax: +91-80-22281761 e-mail: [email protected] 282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza, Pantheon Road Chennai 600 008, Phones: +91-44-28193265, +91-44-28194897 Rel: +91-44-32972089, Fax: +91-44-28193231, e-mail: [email protected] 4-2-1067/1-3, 1st Floor, Balaji Building, Ramkote Cross Road Hyderabad 500 095, Phones: +91-40-66610020, +91-40-24758498 Rel:+91-40-32940929 Fax:+91-40-24758499, e-mail: [email protected] No. 41/3098, B & B1, Kuruvi Building, St. Vincent Road Kochi 682 018, Kerala, Phones: +91-484-4036109, +91-484-2395739 +91-484-2395740 e-mail: [email protected] 1-A Indian Mirror Street, Wellington Square Kolkata 700 013, Phones: +91-33-22651926, +91-33-22276404, +91-33-22276415 Rel: +91-33-32901926, Fax: +91-33-22656075, e-mail: [email protected] Lekhraj Market III, B-2, Sector-4, Faizabad Road, Indira Nagar Lucknow 226 016 Phones: +91-522-3040553, +91-522-3040554 e-mail: [email protected] 106 Amit Industrial Estate, 61 Dr SS Rao Road, Near MGM Hospital, Parel Mumbai 400 012, Phones: +91-22-24124863, +91-22-24104532 Rel: +91-22-32926896, Fax: +91-22-24160828, e-mail: [email protected] “KAMALPUSHPA” 38, Reshimbag, Opp. Mohota Science College, Umred Road Nagpur 440 009 (MS), Phone: Rel: +91-712-3245220, Fax: +91-712-2704275 e-mail: [email protected] Textbook of Ophthalmology © 2008 HV Nema, Nitin Nema All rights reserved. No part of this publication and DVD RO M 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 permissio n of the authors and the publisher. This book has been published in good faith that the materials provided by authors is original. Every effort is made to ensure accuracy of material, but the publisher, printer and authors will not be held responsible for any inadvertent error(s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only. First Edition: 1987 Second Edition: 1991 Reprint: 1993 Third Edition: 1998 Fourth Edition: 2002 Fifth Edition: 2008 ISBN 978-81-8448-307-9 Typeset at JPBMP typesetting unit Printed at Ajanta Press To Pratibha and Sandeep Preface to the Fifth Edition More than twenty years have passed since the textbook of ophthalmology was first published. During the last twenty years, ophthalmology has undergone a phenomenal growth. Successive editions of the textbook have reflected some of the advances made in ophthalmic sciences. In the present fifth edition, all chapters have been updated, and revised or rewritten. The general format of the book is not changed although the clinical presentation has become more colorful. Almost every chapter is liberally illustrated with colored clinical photographs and drawings. Additional material is added to cover newer clinical entities, diagnostic procedures and therapeutic or surgical modalities of treatment of eye diseases. However, no attempt has been made to present an exhaustive text and the book has retained its original virtues of accuracy, clarity, comprehensiveness and consistency of style. An appendix is included in this edition of the book. It contains drawing, description and uses of ophthalmic instruments. Surgical steps of common eye surgeries are demonstrated with the help of video clips. Observation of these video clips will certainly help students to understand and learn basic operative procedures. It will indeed enhance the interest of students in fascinating ophthalmic surgery. At the end of each chapter, a few important references are given to enable the inquisitive student to gather more information on a particular topic of interest. Although the book is written mainly for the undergraduate medical students to grasp the basic ophthalmology, hopefully, it will be beneficial for the postgraduate students and residents in ophthalmology. The book will be useful for the practicing general ophthalmologists in their day-to- day care of patients. HV Nema Nitin Nema Preface to the First Edition In spite of introduction of modern audiovisual techniques: projection slides and television tapes, the bedrock of undergraduate education in ophthalmology remains the standard textbooks. The need for a new and updated textbook is strongly felt with rapid developments and advancements in the ophthalmic sciences. A thorough knowledge of ocular anatomy and physiology is essential for a proper understanding of ophthalmology. Hence, general anatomy and physiology of the eye and its individual structures are comprehensively dealt with. The reader may find the chapter on Examination of the Eye informative and interesting as all the routine advanced clinical methods with diagnostic techniques in ophthalmology are incorporated in brevity. To bring out a better understanding of ocular therapeutics, a separate chapter is included. Common diseases of the eye have been described in some detail and their salient clinical features are highlighted with the help of black and white and coloured photographs. Recent advances in the treatment of ophthalmic disorders have also been covered. The chapter on Operations upon the Eyeball and its Adnexa presents important surgical techniques in present day use. The emergence of community ophthalmology signifies a shift from curative to preventive approach in the speciality. The extensive use of tables and illustrations has been made in an effort to focus the attention of readers on easy differential diagnosis and better retention of facts. The present textbook is primarily written for undergraduate medical students. However, it is hoped that general practitioners and diploma students of ophthalmology would also find it useful in revision and updating of their basic knowledge on the subject. HV Nema Acknowledgements To write a textbook of this kind requires the cooperation and help from colleagues, students, friends and publishers. It is gratifying to mention that we received the help in plenty from all corners. The source of each illustration is acknowledged throughout the pages of the book. However, we would like to express our sincere indebtedness to following colleagues for their generosity in providing a large number of excellent colored photographs and/or video clips from their archives at a short notice. 1. Dr AK Grover, MD,FRCS, Head, Eye Department, Sir Ganga Ram Hospital, New Delhi 2. Professor YR Sharma, MD, Dr RP Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 3. Professor Anita Panda, MD, Dr RP Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 4. Professor MS Bajaj, MD, Dr RP Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 5. Dr Lingam Gopal, MS, FRCS, Director, Sankara Nethralaya, Chennai 6. Dr Jotirmay Biswas, MS, Head, Uveitis and Pathology Department, Sankara Nethralaya, Chennai 7. Dr G. Sitalaxmi, MS, Director, Cornea Service, Sankara Nethralaya, Chennai 8. Dr Virender Sangwan, MD, Director, Cornea Service, LV Prasad Eye Institute, Hyderabad 9. Dr SG Honavar, MD, Director Oculoplasty and Oncology, LV Prasad Eye Institute, Hyderabad 10. Dr Sangmitra Burman, MD, FRCS, Consultant, LV Prasad Eye Institute, Hyderabad 11. Dr Anil Mandal, MD, Consultant, LV Prasad Eye Institute, Hyderabad 12. Dr Usha Kim, MS, Director, Orbit and Oculoplasty, Aravind Eye Hospital, Madurai. 13. Dr D Ramamurthy, MD, Director, The Eye Foundation, Coimbatore 14. Professor KPS Malik, MS, Head, Department of Ophthalmology, Vardhman Medical College, New Delhi 15. Dr Ruchi Goyal, MS, Guru Nanak Eye Center, Maulana Azad Medical College, New Delhi 16. Professor Manoj Shukla, MS, Director, M.U. Institute of Ophthalmology, Aligarh 17. Professor S Kanagami, Tiekyo Medical College, Tokyo 18. Dr Devindra Sood, MD, Consultant, Glaucoma Imaging Center, New Delhi 19. Dr Vikas Mahatme, MD, Director, Mahatme Eye Bank and Hospital, Nagpur 20. Dr Arup Chakrabarti, MS, Director, Chakrabarti Eye Care Center, Trivandrum 21. Dr Cyres Mehta, MS, Consultant, Mehta Eye Hospital, Mumbai 22. Dr VP Singh, MS, Reader, Department of Ophthalmology, BHU, Varanasi 23. Dr Sanjay Thakur, MS, Director, Nataraj Eye Center, Varanasi 24. Mr Siddharth Paramhans, GM, Allergan India, New Delhi. We are indeed grateful to M/S Appasamy Associates, Chennai for permitting