Convergent Strabismus

374 Pages·1982·7.9 MB·English

by  L. Evens (auth.), Dr. Leo Evens (eds.)

Convergent Strabismus
Monographs in Ophthalmology 6
Dr W. JUNK PUBLISHERS THE HAGUE - BOSTON - LONDON
Convergent Strabismus
edited by
L. EVENS
Dr W. JUNK PUBLISHERS THE HAGUE - BOSTON - LONDON
REPRINTED FROM Bull. Soc. beIge Ophtal. 196, 1982
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ISBN-13: 978-94-009-8026-6 e-ISBN-13: 978-94-009-8024-2
001: 10.1007/978-94-009-8024-2
Copyright © 1982 Belgian Society of Ophthalmology, Leuven. Belgium and
Softcover reprint of the hardcover 1st edition 1982
Dr W. Junk Publishers, The Hague, The Netherlands.
All rights reserved. No part of this publication may be reproduced stored in a retrival system,
or transmitted in any form or by any means, mechanical, photocopying, recording, or other
wise, without the prior permission of the publishers.
Dr W. Junk Publishers, P.o. Box 13713,2501 ES The Hague, The Netherlands.
PREFACE
When the Board of Directors of the Belgian Ophthalmological Soci
ety, in its session of November 26th 1978, asked me to prepare a report
on strabismus to be presented at the joint meeting of the Dutch and
Belgian Ophthalmological Societies to be held on June 13th 1981, I felt
greatly honored but still more overwhelmed by the immensity of the
task.
I took advantage of the complete liberty given to me by the Board of
Directors, first to limit the work to one particular form of strabismus,
i.e. the convergent comitant form; second, to seek the help of what I
thought to be the best strabologists in the Low Countries; third, to aim
not at an encyclopedic treatise but at a practical volume destined to the
general ophthalmologist.
This volume is thus limited to the various aspects of convergent
strabismus, more accurately of comitant convergent strabismus. The
omission of the word" comitant" is purposely made to avoid the dif
fic'ulties accompanying the explanation of this term and all the acroba
tics needed to explain that most comitant strabismus are not complete
ly comitant. The choice of this particular form of strabismus seems
logical. First of all, it is the most common form of strabismus. On the
other hand, most principles concerning examination and treatment can
with some modifications be applied to other forms of strabismus.
Prof. R. C. Crone and Prof. A. Th. M. van Balen of the Netherlands,
Dr. H. De Corte, Dr. M. Gobin and Dr. E. Vereecken of Belgium did
me the great honor of accepting to collaborate in this entreprise. This
volume then is the product of the cooperative efforts of these six
authors, each of whom is entirely responsible for the chapters he has
written. As strabismus treatment is an empirical matter and at the
same time in full evolution, it cannot be expected that six independent
authors have exactly the same ideas on each aspect of this treatment. If
not all. many roads lead to Rome. In strabismus, different ways of
treatment can lead to acceptable results and therapeutic variations can
even be useful for progress in this still controversial field.
It was neither the goal of the authors to present an encyclopedic work
nor to produce a volume so complicated as to be readable only by the
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elite of the strabological world. To the contrary, the purpose of this
undertaking was to present a work that would be useful to the general
ophthalmologist. I express the hope that this work will effectively help
him to diagnose more accurately the different forms of esotropia, to
elucidate the causes and contributing factors of each form, to define the
aims and treatment possibilities of each form and to approach com
plete healing.
This volume will not be the last book on convergent strabismus but
the efforts of the authors would be rewarded if it could bring us one
step nearer to the "land where all is clarity, all is simplicity, all is
logic ... "
Brussel, June 13th, 1981.
Dr. Leo Evens, Editor
Lakenselaan 36
1090 Brussels, Belgium
Mr. Vanhove of Janssen Pharmaceutica, 2340 Beerse, Belgium, corrected linguistic errors in
chapters I, 2, 6, 8, 9, for which we are most grateful.
TABLE OF CONTENTS
Preface - L. Evens V
CHAPTER I
INTRODUCTION
L. EVENS
I. Definition. Classification 1
II. Goals of treatment . . 3
III. Goals and possibilities of treatment in the different forms of
convergent comitant esotropia 5
A. Early esotropia . . . . . . 5
B. Late esotropia . . . . . . 8
1. Accommodative esotropia 8
2. Acquired non-accommodative esotropia 11
C. Microstrabismus 11
CHAPTER II
HISTORY OF STRABISMUS TREATMENT
L. EVENS
I. Introduction . . . . . . . . . . . . . . . 19
II. Surgical procedures for convergent squint 22
A. Interventions on the medial rectus muscle 22
1. Myotomy and tenotomy . . 22
2. Partial tenotomy . . . . . 23
3. Controlled (bridled) tenotomy 24
4. Recession . . . . 27
5. Muscle lengthening 28
6. Faden-Operation 30
7. Other weakening procedures 31
B. Interventions on the lateral rectus muscle 32
1. Simple advancement ..... . 33
2. Resection .......... . 33
3. Tucking of the lateral rectus muscle 33
4. Malbran's screwlike twisting 34
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C. Interventions for A and V Phenomena 34
1. Interventions on the horizontal recti 35
2. Interventions on the vertical recti . 36
3. Interventions on the oblique muscles 37
D. Combined surgical procedures 39
III. Non-surgical procedures 40
A. Optical corrections 40
1. Positive glasses 40
2. Bifocals 41
3. Prisms 41
B. Other procedures 42
1. Orthoptics . 42
2. Penalisation 43
3. Miotics 44
CHAPTER III
NORMAL BINOCULAR VISION
R.A. CRONE
I. Introduction . . . . . . . . . . . . . . . . 53
II. Psychophysics of spatial vision . . . . . . . . 55
A. The horopter. Binocular vision without depth 56
B. Depth perception. Range of stereoscopic vision 57
C. Cyclopean localization ..... 60
D. Local and global stereoscopic vision 60
III. Neuroanatomy of binocular vision 63
IV. Neurophysiology of binocular vision 66
V. Motor aspects of binocular vision 69
VI. Diagrammatic representation of binocular vision 71
CHAPTER IV
NEUROMECHANICS OF THE HUMAN
PERIPHERAL OCULOMOTOR SYSTEM
H. DE CORTE
I. Mechanical elements of the peripheral oculomotor system 75
II. Fixation 86
III. Saccades 97
IV. Smooth pursuit 110
V. Vergences . . 114
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CHAPTER V
SYMPTOMATOLOGY
R.A. CRONE
I. Definitions and terminology 125
A. Definition . . . . . . 125
B. Classification 126
II. Sensory anomalies I: suppression and amblyopia 127
A. Suppression .............. 127
B. Amblyopia .............. 129
III. Sensory anomalies II: anomalous binocular vision 129
A. Anomalous correspondence 130
B. Psychophysics ..... 133
C. Neuroanatomy and neurophysiology 135
D. Motor aspects ......... 135
E. Diagrammatic representation of anomalous binocular
vision . . . . . . . . 137
IV. Sensory anomalies III: diplopia 138
A. Transient diplopia 138
B. Persistent diplopia 139
V. Prevalence of convergent strabismus 142
VI. Age of onset of convergent strabismus 143
VII. Strabismus and convergence . 145
A. Types of convergence 145
B. Accommodative aspects 146
C. Tonic and spastic convergence 150
VIII. Nystagmus and related disturbances 152
A. Occlusion nystagmus .... 152
B. Occlusion hypertropia . . . . 154
IX. Incomitance in convergent strabismus 155
X. Clinical syndromes . . . . 159
A. Strabismus, early onset 159
B. Strabismus, late onset . 162
C. Microstrabismus 163
XI. Pathogenesis of convergent strabismus 165
A. Symptom or disease? 165
B. Heredity ..... 168
C. Theories concerning squint 169
D. Inadequacy of the theories 171
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CHAPTER VI
EXAMINATION METHODS
E. VEREECKEN
Introduction . . 179
I. History. 181
II. Inspection 182
Basic examination position 182
A. Torticollis . . . . . 184
B. The eyelid and palpebral fissures 185
C. The pupils . . . . 186
D. Nystagmus 187
III. The corneal reflections 188
IV. The covertest .... 191
A. Type I. The monolateral covertest 191
B. Type II. The alternating covertest 197
V. Prisms examinations 198
A. Horizontal prism test 198
B. Vertical prism test 200
C. Prism bar . . . . 200
VI. Examination of ocular movements 201
A. Versions ...... . 201
1. Horizontal movements 203
2. Vertical movements . 204
3. Diagonal movements 206
B. Ductions ..... 206
C. The Bielschowsky test . . 206
D. Convergence . . . . . . 207
1. The sliding convergence 207
2. The sudden convergence 208
VII. Cycloplegia ..... . 209
VIII. Ocular media and fundus 212
IX. Visual acuity test . . . . 213
X. Measurement of the angle of deviation 214
A. Estimation of the deviation 214
1. Non-foveal fixation (corneal reflection) 214
Maddox scale 214
- Krimsky test 214
- The synopthophore 216
2. Foveal fixation: Hirschberg test 216