Copyright 2012 Singapore Health Services Pte Ltd & Singapore National Eye Centre Pte Ltd

Transcription

1

2 Published by Red Cells Series An imprint under SingHealth Academy, Singapore Health Services Pte Ltd 31 Third Hospital Avenue, #03-03 Bowyer Block C, Singapore Copyright 2012 Singapore Health Services Pte Ltd & Singapore National Eye Centre Pte Ltd All images Singapore National Eye Centre Pte Ltd Please note that some images are repeated in various chapters in this book so as to facilitate easy referencing for readers. All rights reserved. No part of this publication may 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 permission of the copyright owner. Request for permission should be addressed to The Editorial Office, SingHealth Academy, 168 Jalan Bukit Merah, Tower 3 #06-07, Singapore Tel: (65) , fax: (65) publications@singhealthacademy.edu.sg. The publisher makes no representation or warranties with respect to the contents of this book, and specifically disclaims any implied warranties or merchantability or fitness for any particular purpose, and shall in no event be liable for any loss of profit or any other commercial damage, including but not limited to special, incidental, consequential, or other damages. National Library Board Singapore Cataloguing in Publication Data Chee, Soon-Phaik. Essential ophthalmology : a guide for general practitioners / Soon-Phaik Chee, Aliza Jap, Jayant Venkatramani Iyer. Singapore : Red Cells Series, c2012. p. cm. Includes index. ISBN : (pbk.) 1. Ophthalmology. 2. Eye Diseases. I. Jap, Aliza. II. Iyer, Jayant Venkatramani. III. Title. RE dc22 OCN

3 Contents Foreword 6 Preface 7 Authors 8 Acknowledgments 9 Alert! 9 Chapter 1: The Eyeball: An Overview 10 Chapter 2: History and Examination 14 History 15 Examination 18 Additional Reading 30 Amsler Grid Assessment 30 Squint/Strabismus Assessment 31 Dilated Fundoscopy using Direct Ophthalmoscope 33 Chapter 3: An Approach to Common Ocular Symptoms and Signs 36 The Red Eye 37 Loss of Vision 44 Floaters and Flashes of Light 49 Diplopia 50 Proptosis 54 Chapter 4: Eyelids and Conjunctiva 56 The Bare Essentials 57 Eyelids 58 Lacrimation 75 Conjunctiva 81 Additional Reading 91 Eyelid Tumors 91 Other Forms of Conjunctivitis 92 Conjunctival Pigmentation and Tumors 93 Chapter 5: Lens 96 The Bare Essentials 97 Anatomy and Function 97 Cataracts and Other Lens Disorders 98 Additional Reading 101 Cataract Surgery 101 Chapter 6: Glaucoma 104 The Bare Essentials 105 Aqueous Humour and Iridocorneal Angle Anatomy and Function 105 3

4 Glaucoma 107 Glaucoma Management 114 Additional Reading 119 Secondary Open Angle Glaucoma 119 Secondary Angle Closure Glaucoma 121 Congenital Glaucoma 122 Chapter 7: Cornea 124 The Bare Essentials 125 Anatomy and Function 125 Corneal Ulcers/Keratitis 127 Additional Reading 132 Systemic Disorders and Keratitis 132 Arcus Senilis 132 Keratoconus 133 Recurrent Corneal Erosion Syndrome 134 Exposure Keratopathy 134 Neurotrophic Keratopathy 135 Corneal Dystrophies 136 Metabolic and Drug-induced Keratopathy 136 Chapter 8: Ocular Inflammation 138 The Bare Essentials 139 Uvea 140 Sclera and Episclera 149 Endophthalmitis 152 Chapter 9: Retina 156 The Bare Essentials 157 Retina and Vitreous Anatomy and Function 157 Retinopathy 160 Diabetic Retinopathy and Other Diabetic Eye Disease 163 Hypertensive Retinopathy 169 Retinal Vascular Occlusions 172 Vitreous and Retinal Detachment 177 Age-related Macular Degeneration (AMD) 181 Additional Reading 185 Ocular Ischemic Syndrome 185 Macular Hole 185 Central Serous Retinopathy 186 Cystoid Macular Edema 187 Macular Epiretinal Membrane 188 Retinitis Pigmentosa 188 Retinopathy of Prematurity 189 Choroidal Tumors 190 Chapter 10: Systemic Diseases and the Eye 192 The Bare Essentials 193 Thyroid Eye Disease 194 Allergy and the Eye 198 4

5 Additional Reading 201 Other Systemic Conditions and the Eye 201 Chapter 11: Neuro-ophthalmology 206 The Bare Essentials 207 Visual Field Disorders 209 Optic Nerve Disorders and Papilledema 214 Ocular Motility Disorders 222 Other Neurological Conditions Affecting the Eye 230 Additional Reading 233 Etiology of Optic Nerve Disorders 233 Pupil Disorders 234 Gaze Palsies 238 Chapter 12: Pediatric Ophthalmology 242 The Bare Essentials 243 Leukocoria 243 Strabismus 246 Additional Reading 251 Coats Disease 251 Persistent Hyperplastic Primary Vitreous (PHPV) 251 Toxocariasis 252 Toxoplasmosis 252 Coloboma 253 Chapter 13: Refractive Disorders 254 The Bare Essentials 255 Refractive Error 255 Optical Aids 262 Additional Reading 265 Hard Lenses 265 Soft Lenses 266 Refractive Surgery 267 Chapter 14: Ocular Trauma 272 The Bare Essentials 273 Superficial Foreign Bodies 273 Corneal Abrasions 275 Chemical Injuries 276 Corneal Lacerations and Penetrating Trauma 279 Blunt Trauma and Globe Rupture 281 Radiological Workup in Ocular Trauma 286 Chapter 15: Ocular Medications 288 Chapter 16: Pearls and Pitfalls for the General Practitioner and Family Physician 296 Index 300 5

6 Foreword Dr Vivian Balakrishnan Minister for the Environment and Water Resources, Singapore Former Medical Director, Singapore National Eye Centre (1999) Former CEO, Singapore General Hospital ( ) We live in an age of high technology and deep sub-specialization. This has certainly created a quantum leap in new diagnostic and treatment modalities. Patients are also now far more sophisticated, partly because of easy access to medical information through the Internet. However, I am always mindful that the centre of gravity in medicine is not at the specialist s clinic or in cyberspace. Now, more than ever before, we need the best trained, most up-to-date and broad-based general practitioners that we can develop. Health screening, primary diagnoses, integrated care and community based interventions will make the greatest impact on the quality of life of our patients. However, our general practitioners and family physicians face an enormous challenge because they have to be regularly updated with the latest practice guidelines across so many medical specialties. Essential Ophthalmology: A Guide for General Practitioners and Family Physicians aims to empower our general practitioners with the essential knowledge and skills in diagnosing ophthalmic conditions and initiating treatment options. The practical approach advocated, with generous photographs, succinct summaries of differential diagnoses and clinical management will be extremely useful in a busy practice. 6

7 Preface Professor Donald Tan Medical Director, Singapore National Eye Centre Chairman, Singapore Eye Research Institute Chair, Eye-Academic Clinician Program, Duke-NUS Ophthalmic problems and conditions are routinely encountered by doctors in the primary care setting, be it as a general practitioner or as an emergency physician. Given that ophthalmology training during medical school is usually relatively limited in terms of duration and exposure, many doctors may find it daunting to assess or manage patients with ocular complaints which may carry the risk of significant ocular morbidity. And yet these doctors are the patients first point of contact and their immediate source of answers and in some cases, relief. Which patients should they manage on their own and who should be referred for specialist ophthalmic care? Essential Ophthalmology: A Guide for General Practitioners and Family Physicians aims to equip the doctors involved in primary medical care with relevant basic ophthalmic knowledge, to enhance their ability to perform primary eye care. For easy and fast access to relevant information, the authors of this book have presented the information in a manner conducive to quick learning. Each chapter comes with a section highlighting Bare Essentials that the reader needs to know, about the conditions discussed therein. In addition, the bulleted format used in presenting the facts makes for an easy read while the use of algorithms and tables for common ophthalmic symptoms and signs will prove especially useful to the primary care physician in the clinic setting. The large number of photographs will further aid the reader in appreciating and recognizing ophthalmic diseases so that he or she may be able to better diagnose and manage such patients. I am confident this book will prove useful not only to primary care physicians but also to medical students and others who might be interested in maintaining a good basic foundation in the field of ophthalmology. 7

8 Authors Associate Professor Chee Soon Phaik FRCOphth, FRCS(G), FRCS(Ed), MMed(S pore) Head and Senior Consultant Ocular Inflammatory and Immunology Service Cataract Service, Singapore National Eye Centre Associate Professor, Department of Ophthalmology Yong Loo Lin School of Medicine, National University of Singapore Dr Aliza Jap MBBS, FRCS(G), FRCS(Ed), FRCOphth (UK) Senior Consultant Glaucoma Service, Singapore National Eye Centre Head Division of Ophthalmology, Changi General Hospital Dr Jayant Venkatramani Iyer MBBS, GDFM, MMed (Ophth) Registrar Singapore National Eye Centre 8

9 Acknowledgments We would like to thank the medical staff and project team at the Singapore National Eye Centre for their dedication in managing and co-ordinating the development of this publication. Chapter Reviewers Dr Marcus Ang Han Nian Dr Elaine Chee Wen Ling Dr Gemmy Cheung Dr Sonal Kaizad Farzavandi Dr Allan Fong Chee Yang Dr Daphne Chuk Yin Han Project Management Ms Kathy Chen Ophthalmic Imaging Mr Joseph Ho Mr Paul Chua Kwang Yeow Mr Kasi Sandhanam Dr Loh Boon Kwang Dr Loo Jin Liang Dr Mohamad Rosman Dr Claudine Elizabeth Pang Dr Ti Seng Ei Dr Daniel Su Hsien Wen ALERT!! This icon indicates a sight-threatening condition or an ophthalmic emergency. Refer the patient to a specialist or the emergency department immediately. In some instances, the authors have included certain steps the general practitioner/family physician can take to help the patient in the meantime. 9

10 CHAPTER 1 The Eyeball: An Overview

11 The eye is spherical and its wall consists of three concentric coats (Fig. 1.1) Outer fibrous coat sclera and cornea Middle vascular coat (uveal tract) choroid, ciliary body and iris Inner neural coat retina Anterior segment refers to structures anterior to and including the lens Posterior segment refers to structures posterior to the lens The space in front of the lens is filled with aqueous humor The iris divides the anterior segment into anterior and posterior chambers Vitreous humor fills the space behind the lens and helps maintain the structure of the globe Light is focused onto the retina through refractive media including the cornea and lens Fig.1.1: Cross section of the eyeball. 11

12 Chapter 1 Essential ophthalmology The steeply curved cornea performs most of the refraction required for image perception The lens helps to further focus the light through fine adjustments Accommodation takes place when viewing near objects such that the lens is thickened by ciliary muscle contraction to focus the divergent light rays from the object onto the retina Iris diaphragm controls pupil size depending on incident light levels The pupil is dilated in dark conditions to allow more light in and is constricted in well-lit conditions The pupil also constricts to focus light during accommodation Rods and cones located in the retina serve as photoreceptors that transmit received images to the visual cortex through the visual pathway via the optic nerve 12

13 Chapter 3 Essential ophthalmology Loss of Vision Loss of vision can be categorized as: 1. Transient Visual Loss (resolution within 24 hours) 2. Persistent Visual Loss a. Painless i. Acute onset ii. Gradual onset b. Painful TRANSIENT VISUAL LOSS Few Seconds Few Minutes Papilledema (disc swelling due to raised intracranial pressure or malignant hypertension [Fig. 3.14]) Acute changes in blood pressure Amaurosis fugax (usually unilateral) Transient ischemic attack involving visual system Vertebrobasilar insufficiency Ophthalmic migraine Fig. 3.14: Papilledema in right eye as indicated by swollen hyperemic disc (white arrow) and peripapillary hemorrhage (blue arrow). Fig. 3.15: Left central retinal artery occlusion as indicated by pale ischemic retina (white arrow) and "cherry red spot" (blue arrow). 44

14 Chapter An Approach to Common Ocular Symptoms and signs 3 PERSISTENT VISUAL LOSS, ACUTE ONSET, PAINLESS Central retinal vascular occlusion Artery (Fig. 3.15) or vein (Fig. 3.16) Ischemic optic neuropathy Vitreous hemorrhage (Fig. 3.17) Retinal detachment (Fig. 3.18) Macular lesions Exudative age-related macular degeneration (Fig. 3.19) Central serous retinopathy Macular hole Acute neurological lesion, e.g. occipital lobe infarct Fig. 3.16: Right central retinal vein occlusion ( blood-and-thunder appearance ) evidenced by widespread intraretinal hemorrhages (white arrow) and cotton wool spots (blue arrow). Fig. 3.17: Vitreous hemorrhage of right eye causing hazy view of fundus. Fig. 3.18: Left inferior retinal detachment (arrrow) indicated by elevated interior retina with a corrogated appearance. Fig. 3.19: Left eye age-related macular degeneration (wet) with intra- and subretinal hemorrhages (white arrow) and exudates (blue arrow). 45

15 Chapter 3 Essential ophthalmology PERSISTENT VISUAL LOSS, GRADUAL ONSET, PAINLESS Common Less Common Refractive error Cataract (Fig. 3.20) Chronic glaucoma Age-related macular degeneration dry (Fig. 3.21) Diabetic maculopathy (Fig. 3.22) Keratoconus (Fig. 3.23) Other chronic corneal diseases (e.g. corneal dystrophy) Other optic neuropathies e.g. glaucoma, metabolic Fig. 3.20: Slit lamp view through a dilated pupil showing a nuclear sclerotic cataract (arrow). Fig. 3.21: Left eye age-related macular degeneration (dry) as evidenced by drusen (arrow). Fig. 3.22: Right eye severe non-proliferative diabetic retinopathy and maculopathy, with widespread blot hemorrhages in four quadrants and venous beading in one quadrant. Fig. 3.23: Keratoconus with apical protrusion and stromal thinning of the paracentral cornea (arrow). 46

16 Chapter An Approach to Common Ocular Symptoms and signs 3 PERSISTENT VISUAL LOSS ASSOCIATED WITH PAIN Glaucoma Acute angle closure glaucoma (Fig. 3.24) Lens-induced glaucoma (phacomorphic or phacolytic) Anterior uveitis (Fig. 3.25) Optic neuritis (Fig. 3.26) Corneal conditions Infective keratitis (Fig. 3.27) Corneal abrasion (Fig. 3.28, overleaf) Corneal foreign body Fig. 3.24: Acute angle closure glaucoma with mid-dilated pupil (arrow) and mild conjunctival injection. Fig. 3.25: Acute anterior uveitis with hypopyon (white arrow), miosed pupil (blue arrow) and injected conjunctiva. Fig Optic neuritis/papillitis indicated by hyperemic and swollen disc (white arrow) and cotton wool spot (blue arrow). Fig. 3.27: Severe bacterial infective keratitis with large corneal infiltrate (blue arrow), hypopyon (white arrow) and injected conjunctiva. 47

17 Chapter 3 Essential ophthalmology Fig. 3.28: Corneal abrasion (arrow), with fluorescein staining seen under cobalt blue light. Fig. 3.29: Vitreous degeneration with posterior vitreous detachment (arrow) of the right eye. Fig. 3.30: Large retinal tear (arrow) associated with rhegmatogenous retinal detachment. Fig. 3.31: Left inferior retinal detachment (arrrow) indicated by elevated interior retina with a corrogated appearance. Fig. 3.33: Vitreous hemorrhage of right eye causing hazy view of fundus. Fig. 3.32: Right eye cytomegalovirus chorioretinitis ( ketchup-and-cheese appearance) indicated by widespread retinitis (black arrow), cotton wool spots (blue arrow) and intraretinal hemorrhages (white arrow). 48

18 Chapter An Approach to Common Ocular Symptoms and signs 3 FLOATERS AND FLASHES OF LIGHT Flashes of light or photopsia result from mechanical stimulation of the retina, e.g. from vitreous traction on the retina or massaging the eyeball Floaters are mobile opacities in the vitreous, which cast shadows on the retina. Usually most noticeable in bright light or against a white background PHOTOPSIA Vitreous degeneration (Fig. 3.29) with or without Retinal tear (Fig. 3.30) Retinal detachment (Fig. 3.31) Migraine (zig-zag pattern light flash, recurrent for several minutes, may occur as aura preceding migraine attack) Rapid eye movements in the dark FLOATERS Vitreous degeneration (common in myopes and elderly) Retinal tear or detachment Uveitis (Fig. 3.32) Vitreous hemorrhage (Fig. 3.33) 49