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(1)

Binocular

Vision

and

Ocular

(2)

SIXTH

EDITION

Binocular

Vision

and

Ocular

Motility

THEORY AND MANAGEMENT

OF STRABISMUS

Gunter K. von Noorden, MD

Emeritus Professor of Ophthalmology

Cullen Eye Institute

Baylor College of Medicine

Houston, Texas

Clinical Professor of Ophthalmology

University of South Florida College of Medicine

Tampa, Florida

Emilio C. Campos, MD

Professor of Ophthalmology

University of Bologna

Chief of Ophthalmology

S. Orsola-Malpighi Teaching Hospital

Bologna, Italy

Mosby

A Harcourt Health Sciences Company

(3)

Mosby

A Harcourt Health Sciences Company

Editor-in-Chief:Richard Lampert

Acquisitions Editor:Kimberley Cox

Developmental Editor:Danielle Burke

Project Manager:Agnes Byrne

Production Manager:Peter Faber

Illustration Specialist:Lisa Lambert

Book Designer:Ellen Zanolle

Copyright䉷2002, 1996, 1990, 1985, 1980, 1974 by Mosby, Inc.

All rights reserved. No part of this publication may be reproduced or transmit-ted in any form or by any means, electronic or mechanical, including photo-copy, recording, or any information storage and retrieval system, without per-mission in writing from the publisher.

NOTICE

Ophthalmology is an ever-changing field. Standard safety precautions must be followed, but as new research and clinical experience broaden our knowledge, changes in treatment and drug therapy may become necessary or appropriate. Readers are advised to check the most current product information provided by the manufacturer of each drug to be administered to verify the recommended dose, the method and duration of administration, and contraindications. It is the responsibility of the treating physician, relying on experience and knowledge of the patient, to determine dosages and the best treatment for each individual pa-tient. Neither the publisher nor the authors assume any liability for any injury and/or damage to persons or property arising from this publication.

Permission to photocopy or reproduce solely for internal or personal use is per-mitted for libraries or other users registered with the Copyright Clearance Cen-ter, provided that the base fee of $4.00 per chapter plus $.10 per page is paid di-rectly to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, Massachusetts 01923. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional pur-poses, for creating new collected works, or for resale.

Mosby, Inc.

A Harcourt Health Sciences Company

11830 Westline Industrial Drive St. Louis, Missouri 63146

Printed in the United States of America.

Library of Congress Cataloging-in-Publication Data

Von Noorden, Gunter K., 1928–

Binocular vision and ocular motility : theory and management of strabismus / Gun-ter K. von Noorden, Emilio C. Campos.—6th ed.

p. cm.

Includes bibliographical references and index. ISBN 0–323–01129–2

1. Strabismus. 2. Binocular vision. 3. Eye—Movements. I. Title. RE771.V62 2001 616.7⬘62—dc21 2001042586

(4)

HERMANN MARTIN BURIAN

1906-1974

(5)

Preface to the Sixth Edition

A

major change with this edition is the addition

of co-author Dr. Emilio Campos, who is one

of the leaders of European strabismology and

widely respected for his scientific contributions.

Dr. Campos has written a new chapter on

Chemo-denervation and assisted me with the review and

revision of this sixth edition. I selected Dr.

Campos as a co-author because his scientific

back-ground is similar to mine. His mentor Bruno

Bag-olini was trained, as I was, by the late Hermann

Burian, with whom I co-authored the first edition.

Because of this common heritage we agree on all

major issues discussed in this text. Whenever an

occasional difference in opinions existed on minor

subject matters both of our views were stated.

As in previous editions, new material was added

and older text that had lost its relevance was

deleted, except when it was of historical interest.

Binocular Vision and Ocular Motility

has become

a major source of references to the older

strabis-mus literature that is not retrievable through

elec-tronic search techniques. With this in mind, we

have used a conservative approach in deleting

older references so that they would remain

avail-able to the researcher and interested clinician.

We have endeavored to improve clarity in the

text and tables, replaced several old figures with

better examples, and added illustration of surgical

techniques not covered in previous editions.

I

feel deeply honored for having been asked by

Dr. Gunter von Noorden to collaborate with

him on the sixth edition of

Binocular Vision and

Ocular Motility,

and I consider this recognition as

one of the highlights of my career.

I hope that my input to this edition has not

interfered with the homogeneity of this book and

its original message.

Both Dr. von Noorden and I would appreciate

any input from our readers that may help us to

make future editions even more useful.

I would like to express my gratitude to my

collaborators Drs. Costantino Schiavi and

Costan-The formerly voluminous chapter on sensory

adaptation and stereopsis has been divided into

three smaller chapters for easier access. Because

sensorial anomalies in strabismus are only briefly

dealt with in current texts, or receive at best

spuri-ous coverage in most teaching curricula for

resi-dents, the comprehensive discussion of this

sub-ject in this book appears to be fully justified.

The contributions and teaching of Hermann

Bu-rian remain apparent throughout this text but

espe-cially in Part One. We submit this volume not

only as his legacy but also that of his teacher,

Alfred Bielschowsky, who has influenced

strabis-mology during the first half of the 20th century

like no one else.

My thanks are due to Mrs. Louise Thomas, my

faithful former secretary, for obtaining copies of

articles from the local medical libraries and

illus-trations through the Baylor Department of Medical

Illustrations, and to Mr. Mike Piorunski, librarian

of the Friedenwald Library of the Wilmer Institute,

for locating and verifying older references. Last,

but not least, I thank my dear wife for her

contin-ued support and patience during the work on this

edition.

The authors have no proprietary interest in any

of the commercial products, drugs, or instruments

mentioned in this book.

Gunter K. von Noorden

tino Bellusci, who have helped me in the

prepara-tion of clinical illustraprepara-tions and surgical drawings.

Many thanks also to Stefania Piaggi, C.O., for

having located obscure references and for her help

with the computer search of the literature.

I am grateful to all my collaborators and to

those close to me for their patience during the

preparation of the manuscript and ask their

for-giveness for any lack of attention during this most

stimulating but time-consuming venture.

(6)

Preface to the First Edition

He who is theoretic as well as practical is

therefore doubly armed: able not only to prove

the propriety of his design but equally so to

carry it into execution.

VITRUVIUS

T

his volume is the product of the cooperative

efforts of the two authors. Parts I and II were

written by Burian, and Parts III and IV by von

Noorden; however, both authors take full

responsi-bility for the complete text.

In this work, our aim is to provide the

practic-ing ophthalmologist as well as the buddpractic-ing one

with the theoretic knowledge and practical

know-how that will enable him to pursue the field of

neuromuscular anomalies of the eyes in the

man-ner set forth in the precept of Vitruvius.

The sound physiologic tradition of Hering,

Helmholtz, Donders, Tschermak, Hofmann, and

their schools forms the solid ground upon which

was built the clinical work of Javal, Worth,

Bielschowsky, Duane, Lancaster, and, more

re-cently, Harms, Cu¨ppers, Lyle, Bagolini, ourselves,

and many others. Our purpose has been to convey

this physiologic basis as concisely and simply as

possible, always with the practicing

ophthalmolo-gist in mind and wherever possible emphasizing

its immediate clinical application. But much has

happened in our field since the days of the old

masters, and due consideration is given to the

exciting and significant modern studies in the

psy-chophysical and neurophysiologic areas as well as

in the field of clinical management of strabismus.

This volume is not a handbook or a system,

how-ever, and is not intended to be systematically or

historically complete. We, therefore, have omitted

many points that are to be found in reference

works. Neither does this book supplant the

Atlas

of Strabismus

by von Noorden and Maumenee,

which continues to be a useful guide to the

diag-nostic aspects of strabismus.

The theoretic foundation has served us as a

means to make the strictly clinical chapters both

‘‘theoretic and practical,’’ telling the

ophthalmolo-gist not only the ‘‘what and how’’ but also the

‘‘why.’’ We hope that the long hours of labor

expended on this volume may be of real

use-fulness in the study of strabismus, particularly to

the younger generation of ophthalmologists.

Hermann M. Burian

Gunter K. von Noorden

(7)

Contents

P A R T O N E

Physiology of the Sensorimotor

Cooperation of the Eyes

1

General Introduction

. . . 3

The Eyes as a Sensorimotor Unit 3 The Tasks of the Motor System 3

Nature and Control of Ocular Movements 3

Voluntary and Involuntary Eye Movements 3 Cybernetic Control of the Eye Movements 4 Apparent Movement of the Environment 5

Empiricism and Nativism 5

2

Binocular Vision and Space

Perception

. . . 7

Fusion, Diplopia, and the Law of Sensory Correspondence 7

Relative Subjective Visual Directions 7 Retinomotor Values 8

Common Relative Subjective Visual Directions 9 Retinal Correspondence 10

Sensory Fusion 10 Motor Fusion 11

Retinal Rivalry 11

Objective (Physical) and Subjective (Visual) Space 12

Discrepancies of Objective and Subjective Metrics 14

Distribution of Corresponding Retinal Elements 15

The Foveae as Corresponding Elements 15 The Horopter 16

Physiologic Diplopia 18

Clinical Significance 18 Suppression 19

Panum’s Area of Single Binocular Vision 20 Fixation Disparity 21

Stereopsis 21

Physiologic Basis of Stereopsis 22 Local vs. Global Stereopsis 23 Stereopsis and Fusion 24 Stereoscopic Acuity 25

xi

Monocular (Nonstereoscopic) Clues to Spatial Orientation 25

Interaction of Stereoscopic and Monocular Clues 27 Clinical Significance of Monocular Clues 27

Experimental Determination of the Longitudinal Horopter and the Criteria of Retinal Correspondence 28

Criterion of Single Vision 28 Apparent Frontal Plane Criterion 28 Criterion of Common Visual Directions 29 Criterion of Highest Stereoscopic Sensitivity 29

Egocentric (Absolute) Localization 29

Egocentric Localization and Convergence 29 Egocentric Localization and Proprioception 30 Clinical Significance of Relative and Egocentric

Localization 31

Theories of Binocular Vision 31

Correspondence and Disparity 31

Neurophysiologic Theory of Binocular Vision and Stereopsis 31

Older Theories of Binocular Vision 33

Advantages of Binocular Vision 35

3

Summary of the Gross Anatomy

of the Extraocular Muscles

. . . 38

Rectus Muscles 39

Muscle Pulleys 41

Oblique Muscles 42 Fascial System 44

Tenon’s Capsule 44

Muscle Sheaths and Their Extensions 45 Ligament of Lockwood 47

Check Ligaments 47

Intracapsular Portion of the Muscle 47 Functional Role of the Fascial System 48

Developmental Anomalies of Extraocular Muscles and the Fascial System 48

Innervation of Extraocular Muscles 49 Blood Supply of Extraocular Muscles 49

4

Physiology of the Ocular

Movements

. . . 52

Basic Kinematics 52

Translatory and Rotary Movements 52 Center of Rotation 52

(8)

xii

Contents

Definitions of Terms and Action of Individual Muscles 52

Further Considerations of Mechanics of Extraocular Muscles 56

The Fundamental Laws of Ocular Motility 59

Donders’ and Listing’s Laws 59

Sherrington’s Law of Reciprocal Innervation 63 Hering’s Law of Equal Innervation 64 Experimental Studies of Integration of Ocular

Movements by Muscle Transposition 67

Survey of Ocular Movements and Their Characteristics 67

Terminology of Ocular Movements 67 Versions 68

Vergences 71

Characteristics of Version and Vergence Movements 76

Fixation and the Field of Fixation 79

Fixation 79 Field of Fixation 79

5

The Near Vision Complex

. . . 85

Accommodation 85

Mechanism of Accommodation 85

Units of Measurement of Accommodation and Definition of the Prism Diopter 86 Sympathetic Innervation 86

Convergence 86

Units of Measurement of Convergence 87 Components of Convergence 88

Pupillary Constriction 99

6

Histology and Physiology of

the Extraocular Muscles

. . . 101

Structure and Function of the Extraocular Muscles 101

General Histologic Characteristics 101 Nerve Supply 102

Physiologic and Pharmacologic Properties 102 Slow and Fast Twitch Fibers 103

Structural and Functional Correlations 107 Muscle Spindles and Palisade Endings in the

Extraocular Muscles 109 Electromyography 109

Sources of Tonus of the Extraocular Muscles 111

7

Visual Acuity, Geometric Optical

Effects of Spectacles, and

Aniseikonia

. . . 114

Visual Acuity 114

Basic Physiologic Concepts 114 Variables Affecting Visual Acuity 115

Geometric Optical Effects of Spectacles 118 Aniseikonia 119

P A R T T W O

Introduction to Neuromuscular

Anomalies of the Eyes

8

Classification of Neuromuscular

Anomalies of the Eyes

. . . 127

Heterophoria and Heterotropia 127 Relative and Absolute Position of Rest 128 Ocular Alignment 129

Direction of Deviation 129 Comitance and Incomitance 131 Constancy of Deviation 131 State of Vergence Systems 132 Type of Fixation 132

Time of Onset of Deviation 132 Paralytic Strabismus 132

Paralysis and Paresis 132 Muscles Affected 133 Duration and Cause 133 Seat of Lesion 133

Mechanical-Restrictive Strabismus 133 Orbital Strabismus 133

9

Etiology of Heterophoria and

Heterotropia

. . . 134

Factors Responsible for the Manifestation of a Deviation 134

Abnormalities of Fusion Mechanism 134 Reflexologic Theories 137

Factors Causing the Underlying Deviation 138

Mechanical (Muscular) Theories 138

Structural Anomalies of Extraocular Muscles 139 Role of Accommodation and Refraction in Comitant

Strabismus 139 Fixation Disparity 140

Other Innervational (Neurologic) Factors in Comitant Strabismus 141

Brain Damage 143 Embryopathy 145

Facial and Orbital Deformities 145

Genetics of Comitant Strabismus 145

Summary 148

Concluding Remarks 148

10

Symptoms in Heterophoria

and Heterotropia and the

Psychological Effects

of Strabismus

. . . 153

Asthenopia and Diplopia 153

Psychological Effects of Strabismus 156

11

Examination of the Patient—I

Preliminaries . . . 158

History 158

(9)

Contents

xiii

Estimation of Visual Acuity in Infants 159 Measurement of Visual Acuity in Preschool-Age

Children 162

Measurement of Visual Acuity in School-Age Children and Adults 163

Refraction 163

Changes of Refraction with Age 165

12

Examination of the Patient—II

Motor Signs in Heterophoria and

Heterotropia . . . 168

Inspection of the Eyes and Head Position 168

Inspection of the Lids and Lid Fissures 168 Position of the Globes—Angle Kappa 169

Measurement of Angle Kappa 171 Size of Angle Kappa 172

Clinical Significance of Angle Kappa 172

Observation of Head Position 173

Determination of Presence of a Deviation—Cover and Cover-Uncover Tests 174

Measurement of Deviation 176

Prism and Cover Test 177

Physiologic Basis 177 Performance 178 Limitations 181

Prism and Cover Test in Diagnostic Positions of Gaze 182

Measurement with the Major Amblyoscope 183 Corneal Reflection Tests 185

Photographic Methods 186 Bru¨ckner Test 187 Subjective Tests 187

Diplopia Tests (Red-Glass Test and Others) 187 Haploscopic Tests 190

Measurement of Cyclodeviations 194

Qualitative Diagnosis Based on Position of Double Images 194

Maddox Double Rod Test 194 Bagolini Striated Glasses 195 Major Amblyoscope 196

Ophthalmoscopy and Fundus Photography 196 The New Cyclo Test 198

Scotometry 198

Determination of the Subjective Horizontal or Vertical 198

Measurement of Dissociated Vertical Deviations 198 The Head Tilt Test 198

Examination of the Motor Cooperation of the Eyes 199

Ductions and Versions 199

Elevation or Depression of the Adducted Eye (Upshoot or Downshoot in Adduction) 201

Measurement of Vergences 202

Measurement With Prisms 202

Measurement With a Major Amblyoscope 206 Fusional Movements Elicited by Peripheral Retinal

Stimuli in Strabismus 206

Near Point of Convergence 206

Maintenance of Convergence 207

13

Examination of the Patient—III

Sensory Signs, Symptoms,

and Binocular Adaptations

in Strabismus . . . 211

Confusion and Diplopia 212

Monocular Diplopia 213 Binocular Diplopia 214

Suppression 215

Mechanism and Seat 215 Clinical Features 216 Tests for Suppression 217

Binocular Perimetry and Haploscopy 217 Prisms 218

The Four-Prism Diopter Base-Out Prism Test 218 Monocular Visual Acuity Measured Under

Binocular Conditions 219 The Worth Four-Dot Test 219

Suppressing Versus Ignoring a Double Image 220 Measurement of Depth of Suppression 221

Blind Spot Mechanism 221 Anomalous Correspondence 222

Basic Phenomenon and Mechanism 222 Tests 225

Afterimage Test 225

Striated Glasses Test of Bagolini 227 Testing With the Major Amblyoscope 228 Diplopia Test 230

Testing With Projection Devices 230 Foveo-Foveal Test of Cu¨ppers 230

Evaluation of Tests 231 Neurophysiologic Basis 233

Suppression and Anomalous Correspondence 233 Development and Clinical Picture 234

Development 234 Clinical Picture 235

Quality of Binocular Vision in Anomalous Correspondence 239

Prevalence 239 Theories 240

Review and Summary 241

14

Examination of the Patient—IV

Amblyopia . . . 246

Prevalence, Social and Psychosocial Factors 246 Classification and Terminology 248

Strabismic Amblyopia 249 Anisometropic Amblyopia 250

Visual Deprivation Amblyopia (Amblyopia Ex Anopsia) 252

Idiopathic Amblyopia 253 Organic Amblyopia 253

Amblyopia Secondary to Nystagmus 254

Clinical Features of Strabismic Amblyopia 254

Fixation Preference 254 Visual Acuity 255

Fixation Pattern of the Amblyopic Eye 260 The Sensitive Period 268

Pathogenesis and Pathophysiology of Amblyopia 269

Psychophysical Studies 269 Higher Nervous Center Activities 277

(10)

xiv

Contents

Eye Movements in Amblyopia 279 Electrophysiologic Studies 279

Amblyopia vs. Suppression 282

Experimental Amblyopia in Animal Models and Histologic Abnormalities in Brains of Human Amblyopes 282

The Essence of Amblyopia 286

15

Examination of the Patient—V

Depth Perception . . . 298

Development of Stereopsis 298 Stereopsis and Strabismus 298 Testing for Stereopsis 299

Major Amblyoscope or Stereoscope 299 Stereogram 299

Titmus Stereo Test 299 Random-Dot Stereograms 301 TNO Test 302

Lang Test 303 Two-Pencil Test 304

P A R T T H R E E

Clinical Characteristics of

Neuromuscular Anomalies of

the Eye

16

Esodeviations

. . . 311

Esophoria and Intermittent Esotropia 311

Etiology 311 Clinical Signs 311 Symptoms 312

Sensorial Adaptation 312 Diagnosis 312

Therapy 313

Accommodative Esotropia 314

Refractive Accommodative Esotropia (Normal AC/A Ratio) 314

Definition 314 Etiology 314

Clinical Characteristics 316 Therapy 316

Nonrefractive Accommodative Esotropia (High AC/A Ratio) 318

Definition 318

Clinical Characteristics 318 Therapy 318

Hypoaccommodative Esotropia 319

Definition 319

Clinical Characteristics 319

Partially Accommodative Esotropia 319

Definition 319

Clinical Characteristics 320 Therapy 320

Nonaccommodative Esotropia 320

Essential Infantile Esotropia 320

Definition 320

Terminology, Prevalence, Etiology 320

Differential Diagnosis 321 Clinical Characteristics 321 Therapy 329

Nonaccommodative Convergence Excess Esotropia (Normal AC/A Ratio) 336

Definition 336

Clinical Characteristics 336 Treatment 336

Acquired or Basic Esotropia 336

Definition 336

Clinical Characteristics 337 Therapy 337

Esotropia in Myopia 338

Acute Acquired Comitant Esotropia 338

Acute Strabismus After Artificial Interruption of Fusion 338

Acute Esotropia Without Preceding Disruption of Fusion (Burian-Franceschetti Type) 339 Acute Esotropia of Neurologic Origin 339

Microtropia 340

Historical Review 340

Current Concepts and Clinical Significance 342 Diagnosis 343

Therapy 344

Recurrent Esotropia 345 Secondary Esotropia 345

Sensory Esotropia 345

Etiology and Clinical Characteristics 345 Therapy 346

Consecutive Esotropia 347

Management of Surgical Overcorrections 347 Esotropia Associated with Vertical Deviations 348

Clinical Characteristics and Diagnosis 348 Therapy 349

17

Exodeviations

. . . 356

Classification and Etiology 356 Primary Exodeviations 358

Clinical Characteristics 358 Therapy 365

Surgical Treatment 367

Dissociated Exodeviations 372 Secondary Exodeviations 372

Sensory Exotropia 372 Consecutive Exotropia 372

18

Cyclovertical Deviations

. . . 377

Comitant Hyperdeviations 377

Etiology and Clinical Characteristics 377 Therapy 378

Dissociated Vertical Deviations 378

Terminology 378

Clinical Characteristics 378 Measurement 380

Etiology 381

Differential Diagnosis 383 Therapy 383

Dissociated Horizontal Deviations 385 Elevation in Adduction (Strabismus

(11)

Contents

xv

Clinical Characteristics 385 Etiology 386

Therapy 387

Depression in Adduction (Strabismus Deorsoadductorius) 387

Cyclodeviations 389

Diagnosis 389

Clinical Characteristics 389 Therapy 391

19

A

and

V

Patterns

. . . 396

Etiology 398

Horizontal School 398 Vertical School 399 Oblique School 399 Orbital Factors 399

Craniofacial Anomalies 399 Heterotropia of Muscle Pulleys 400

Anomalies of Muscle Insertions and Cyclotorsion 401

Conclusions 402

Prevalence 404

Clinical Findings and Diagnosis 404 Treatment 406

Indications for Surgery 406 Surgical Methods 407

Surgery on the Horizontal Rectus Muscles 407 Surgery on the Oblique Muscles 407 Transposition of Horizontal or Vertical Rectus

Muscles 409

Slanting of the Horizontal Muscle Insertions 410

Choice of Surgical Procedure 410

20

Paralytic Strabismus

. . . 414

Diagnosis and Clinical Characteristics 414

Ductions and Versions 415 Measurement of the Deviation 415 Head Tilt Test 416

Compensatory Anomalies of Head Position 417 Sensory Anomalies 421

Past-Pointing 421 Electromyography 422

Neurogenic Paralysis vs. Myogenic or Structural Restriction of Eye Movements 422

Forced Duction Test 423

Estimation of Generated Muscle Force 425 Eye Movement Velocity 426

Paralytic vs. Nonparalytic Strabismus 427 Congenital vs. Acquired Paralysis 427 Orbital Imaging Techniques 429 Evaluation of Visual Impairment Caused by

Diplopia 429

Paralysis of Individual Extraocular Muscles 429

Cranial Nerve III Paralysis 430 Cranial Nerve IV Paralysis 434 Cranial Nerve VI Paralysis 439

Skew Deviation 442

Double Elevator Paralysis 442 Double Depressor Paralysis 443

Supranuclear and Internuclear Paralysis 444

Therapy of Paralytic Strabismus 444

Nonsurgical Therapy 445 Surgical Therapy 445 Alternative Methods 451

21

Special Forms of Strabismus

. . . 458

Retraction Syndrome (Duane Syndrome) 458

Laterality and Sex Distribution 458 Etiology 459

Clinical Findings and Diagnosis 461 Therapy 465

Brown Syndrome 466

Incidence, Laterality, and Heredity 466 Associated Anomalies 467

Natural History 467 Etiology 467

Diagnosis and Differential Diagnosis 470 Therapy 470

Adherence Syndrome 471 Strabismus Fixus 471

Clinical Findings and Etiology 471 Therapy 472

Strabismus in High Myopes 473 Fibrosis of the Extraocular Muscles 474 Graves’ Endocrine Ophthalmopathy 476

Etiology 476

Diagnosis and Clinical Findings 476 Therapy 478

Acute Orbital Myositis 480 Cyclic Heterotropia 480

Clinical Findings and Etiology 480 Therapy 482

Acquired Motor Fusion Deficiency 482 Fracture of the Orbital Floor 483

Clinical Findings and Etiology 483 Therapy 484

Fracture of the Medial Orbital Wall 486 Superior Oblique Myokymia 487

Clinical Findings and Etiology 487 Therapy 487

Ocular Myasthenia Gravis 488

Clinical Findings 488 Diagnosis 488 Therapy 489

Chronic Progressive External Ophthalmoplegia (Ocular Myopathy of von Graefe) 489

Clinical Findings and Etiology 489 Therapy 490

22

Anomalies of Convergence and

Divergence

. . . 500

Anomalies of Convergence 502

Convergence Insufficiency 502

Convergence Insufficiency Associated with Accommodative Insufficiency 503 Convergence Paralysis 503 Convergence Spasm 504

Anomalies of Divergence 505

Divergence Insufficiency 505 Divergence Paralysis 505

(12)

xvi

Contents

23

Nystagmus

. . . 508

Manifest Congenital Nystagmus 508

Sensory and Motor Type 508 Clinical Characteristics 509 Compensatory Mechanisms 511

Latent and Manifest-Latent Congenital Nystagmus 516

Clinical Characteristics 516

Treatment 520

Medical Treatment 521 Surgical Treatment 522

P A R T F O U R

Principles of Therapy

24

Principles of Nonsurgical

Treatment

. . . 537

Optical Treatment 537

Refractive Correction 537 Prisms 540

Pharmacologic Treatment 541

Miotics 541 Atropine 543 Chemodenervation 543

Orthoptics 543

Applications 543

Indications and Contraindications 544 Treatment of Amblyopia 545 Red Filter Treatment 550 Prisms 550

Penalization 550 Drugs 552 Pleoptics 552 CAM Treatment 553 Other Types of Treatment 553 Rationale for Treatment 553

25

Chemodenervation of Extraocular

Muscles—Botulinum Toxin

. . . 559

Mechanisms of Action 559 Injection Technique 560 Indications 561

Botox in Infantile Esotropia 561

Botox in Other Forms of Comitant Strabismus 562 Botox in Paralytic Strabismus 562

Botox in Endocrine Ophthalmopathy and Other Ocular Motility Disturbances 563 Botox in Nystagmus 563

Other Ophthalmologic Indications 563

Alternatives to Botox for Chemodenervation 563

26

Principles of Surgical Treatment

. 566

History and General Comments 566 Choice of Operation 568

Motility Analysis 569

Symmetrical vs. Asymmetrical Operations 570 Amount of Operation 571

Prism Adaptation Test 572

Operations to Weaken the Action of a Muscle 573 Operations to Strengthen the Action of a

Muscle 579

Combined Recession-Resection Operation 580

Single vs. Multiple Procedures 580

Preparation of Patient and Parents for Surgery 581 Anesthesia 581

General Anesthesia 581 Local Anesthesia 582

Instruments, Sutures, Needles 582 Surgical Techniques 583

Preparation of the Eye 583 Fixation of the Globe 584

Conjunctival Incision and Exposure of a Rectus Muscle 584

Recession of a Rectus Muscle 587 Resection of a Rectus Muscle 588 Adjustable Sutures 591

Marginal Myotomy of a Rectus Muscle 597 Myectomy of the Inferior Oblique Muscle 598 Recession of the Inferior Oblique Muscle 600 Tenectomy of the Superior Oblique Muscle 602 Recession of the Superior Oblique Muscle 603 Tucking of the Superior Oblique Muscle 603 Anterior and Lateral Displacement of the Superior

Oblique Tendon for Excyclotropia (Harada-Ito Procedure) 607

Posterior Fixation Suture 609 Muscle Transposition Procedures 612

Recession of Conjunctiva and Tenon’s Capsule 617 Traction Sutures 617

Use of Plastic Materials 618

Complications 618

Surgical Complications 618 Complications of Anesthesia 619 Postoperative Complications 620

Overcorrections 623 Postoperative Care 623

Length of Hospitalization and Postoperative Checkups 623

Dressing 624 Medication 624

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