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Eye Movement Disorders in Clinical Practice Shirley H. Wray, MD, PhD, FRCP PROFESSOR OF NEUROLOGY HARVARD MEDICAL SCHOOL MASTER CLINICIAN DEPARTMENT OF NEUROLOGY MASSACHUSETTS GENERAL HOSPITAL BOSTON, MASSACHUSETTS Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trademark of Oxford University Press in the UK and certain other countries. Published in the United States of America by Oxford University Press 198 Madison Avenue, New York, NY 10016 © Shirley H. Wray 2014 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, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, by license, or under terms agreed with the appropriate reproduction rights organization. Inquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above. You must not circulate this work in any other form and you must impose this same condition on any acquirer. Library of Congress Cataloging-in-Publication Data Wray, Shirley H. Eye movement disorders in clinical practice / Shirley H. Wray. p. ; cm. ISBN 978–0–19–992180–5 (alk. paper)—ISBN 978–0–19–992181–2 (alk. paper)— ISBN 978–0–19–998149–6 (alk. paper) I. Title. [DNLM: 1. Ocular Motility Disorders—diagnosis—Case Reports. 2. Ocular Motility Disorders—etiology—Case Reports. 3. Cranial Nerve Diseases—complications—Case Reports. 4. Cranial Nerve Diseases—diagnosis—Case Reports. 5. Diagnosis, Differential—Case Reports. 6. Neuropsychological Tests—Case Reports. WW 410] RE731 617.7′62—dc23 2013010302 The science of medicine is a rapidly changing field. As new research and clinical experience broaden our knowledge, changes in treatment and drug therapy occur. The author and publisher of this work have checked with sources believed to be reliable in their efforts to provide information that is accurate and complete, and in accordance with the standards accepted at the time of publication. However, in light of the possibility of human error or changes in the practice of medicine, neither the author, nor the publisher, nor any other party who has been involved in the preparation or publication of this work warrants that the information contained herein is in every respect accurate or complete. Readers are encouraged to confirm the information contained herein with other reliable sources, and are strongly advised to check the product information sheet provided by the pharmaceutical company for each drug they plan to administer. 1 3 5 7 9 8 6 4 2 Printed in the United States of America on acid-free paper For Anne With All My Thanks CONTENTS Preface 1. How the Brain Moves the Eyes 2. The Eyelid and Its Signs 3. Ptosis and Neuromuscular Syndromes 4. The Extraocular Muscles and Diplopia 5. Cranial Nerves Three, Four, Six, and Their Syndromes 6. Horizontal Gaze and Syndromes of the Pons 7. Vertical Gaze and Syndromes of the Midbrain 8. Dizziness, Vertigo, and Syndromes of the Medulla 9. The Cerebellum and Its Syndromes 10. Oscillopsia, Nystagmus, Saccadic Oscillations, and Intrusions Index of Case Studies with Video Displays Index PREFACE T his is a very personal book. It reflects my experience as a neurologist for more than 50 years. In the course of that time I knew and learned from the great neurologists at Queen Square, London, during my residency and fellowship in neurophysiology, and at the Massachusetts General Hospital when I arrived there in 1967. Their influence is part of this book and my specific indebtedness is to the late Raymond D. Adams and Charles Miller Fisher. Eye movement disorders are common in clinical practice and yet they raise many difficult questions with respect to diagnosis, prognosis and management. The approach I have taken in this book is clinically oriented but the contents covers much of the relevant literature, and include many aspects of eye movement disorders. I realize that some of the views expressed, for example, my guides to clinical points to remember, are personal preferences but they have worked for me and I hope they may work for others. I have attempted as well to clarify the complex terminology and methods of ophthalmologists for neurologists and neurosurgeons, and to provide a comprehensive physiologic framework to aid in diagnosis. While written with neurologists and neurosurgeons specifically in mind, I hope the students of other disciplines, among them ophthalmology, neuro-otology, neuro-pediatrics, neurooncology and internal medicine, will find my approach useful. Readers who would like to view additional videos of a variety of other eye movement disorders can access my website by accessing the NOVEL website of the North American Neuro-Ophthalmology Society: http://NOVEL.utah.edu or by accessing my collection at Harvard Medical School Countway Library: http://Repository.Countway.Harvard.edu/Wray. I am very grateful to many colleagues who have made the writing of this book possible. This especially applies to the late David Cogan at the Massachusetts Eye and Ear Infirmary who strongly encouraged me to film and video many unique cases for teaching purposes and I am especially grateful to my patients who contributed so much to my clinical experience and whose permission made possible the case studies published in this book. The expert help of Nancy Lombardo, Associate Director of Information Technology, Spencer S. Eccles Health Sciences Library, University of Utah and of Stephen Smith, Department of Surgery, Massachusetts General Hospital made the DVD collection possible. A number of people provided encouragement throughout this project and I would like to express my gratitude to John Leigh who critically reviewed the manuscript and David Zee who reviewed the case videos with me and to Agnes Wong and Hal Blumenfeld for their unfailing authorial generosity. Any errors that may remain are my own. I am also particularly indebted to Anne Jardim for her editing skill, helpful criticism and encouragement over the last several years, and to my secretary, Fran Christie, for her unstinting help in getting the manuscript ready for publication and who with Karen Hoenig and Marylou Moar typed draft after draft after draft until we were satisfied. My grateful thanks also go to members of the Massachusetts General Hospital Photographic Department, Michelle Rose and Paul Batista, for their remarkable professional competence and to the wonderful creative team at the Cambridge Side Galleria Apple Store for their support in creating the DVD. Thank you Tommy, Dan, Tony, Brook, and Akira. Shirley H. Wray | 1 | HOW THE BRAIN MOVES THE EYES THE CEREBRAL CORTEX The brain sees what the eyes look at. Multiple, well-delineated visual areas analyze the visual scene, with each area having its own retinotopic map of the visual field. The visual areas act simultaneously to analyze the image on the retina, sending this information to the cortical areas controlling eye movements, where the image seen combines with internally stored neural information to produce a more comprehensive blueprint of the visual environment. The speed with which this is accomplished is remarkable. The specialized extrastriate areas send output to satellite areas and to other regions of the cortex. There, potential targets for gaze are analyzed and selected and quick decisions made: whether or not to execute a saccadic eye movement from one target to another, for example, or whether to pursue a moving target in a field of moving and stationary potential targets or to stay fixed on a target waiting for it to move. Once the decision is made, two major types of eye movements are generated by the cerebral cortex. Volitional intentional saccades, which are internally triggered to move the eyes toward a target, and reflexive saccades, which respond to the sudden appearance of a target on the retina. Both modes of saccadic generation act in concert and, once initiated, they cannot be stopped. They originate