Hood, Alison S. (1999) The dependence of binocular contrast sensitivity on binocular single vision

369 Pages·2015·13.15 MB·English

Hood, Alison S. (1999) The dependence of binocular contrast sensitivity
on binocular single vision. PhD thesis

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The Dependence of Binocular Contrast Sensitivity on
Binocular Single Vision
A thesis submitted for the degree of
Doctor of Philosophy
By
Alison S. Hood
Neuroscience and Biomedical Systems
October 1999
Institute of Biomedical and Life Sciences
University of Glasgow
Contents
Contents
Page Number
Summary of Contents
Terminology
IX
List of Abbreviations XIV
List of Figures
XVI
List of Tables
XXIV
Abstract
XXVlll
1.0 Introduction 1
1.1 Binocular Single Vision (BSV) 1
1.1.1 Eye Position at Rest (Heterophoria) 6
1.2 Heterotropia 8
1.2.1 Accommodative Esotropia 10
1.2.2 Non-Accommodative Strabismus 11
1.2.2.1 Large Angle Esotropia 13
1.2.2.2 Moderate Angle Strabismus 16
1.2.2.3 Small Angle Strabismus 17
Microtropia with Identity 17
Microtropia without Identity 18
1.2.3 Exotropia 19
1.2.3.1 Primary Exotropia 20
1.2.3.2 Consecutive Exotropia 21
1.3 Sequential Changes in Strabismus 21
1.3.1 Confusion and Diplopia 21
1.3.2 Suppression 24
1.3.2.1 Suppression in Esotropes 24
1.3.2.2 Suppression in Exotropes 25
1.3.3 Strabismic ~;;' 27
-:;!If,,,,}'u
1.3.4 Abnormal Retinal Correspondence and
Anomalous BSV 28
Contents
1.3.5 Eccentric Fixation 30
1.4 Refractive Errors 31
1.4.1 Ametropia 31
1.4.2 Anisometropia 32
1.5 Management of Strabismus and Amblyopia 33
1.5.1 Treatment ofA mblyopia 34
1.5.1.1 Anisometropic Amblyopia 34
1.5.1.2 Strabismic Amblyopia 35
1.5.2 Surgical Correction of the Strabismus 37
1.6 The Visual Pathway 38
1.6.1 Retinal Neurones 38
1.6.1.1 Cat Retinal Ganglion Cells 39
1.6.1.2 Primate Retinal Ganglion Cells 41
1.6.2 The Visual Pathway 42
1.6.3 The Visual Cortex 43
1.6.3.1 Cat Visual Cortex 43
1.6.3.2 Classification ofN eurones 44
1.6.3.3 Primate Visual Cortex 46
1.6.3.4 Cytochrome Oxidase Organisation 48
1.6.3.5 Primate Cortical Organisation 50
1.6.3.6 Stereoscopic Vision 50
1.6.4 Pre-Striate Cortex 52
1.6.4.1 Global Stereopsis 56
1.6.4.2 Stereopsis in Man 57
1.7 Normal Development of the Visual System 57
1. 7.1 Humans and Primate 57
1. 7.2 Cat 58
1.8 Effects of Abnormal Visual Experience 60
1.8.1 Monocular Occlusion 60
I.B.l.l Physiological Studies in Cat 60
I.B.1.2 Physiological Studies in Primate 61
1. B.l. 3 Morphological and Histological Studies 62
1.8.2 Strabismus 63
ii
Contents
1. B. 2.1 Physiological Studies in Cat 63
1.B.2.2 Physiological Studies in Primate 64
1.8.3 Anisometropia 65
1.B.3.1 Physiological Studies in Primate 65
1.9 Amblyopia 65
1.9.1 Physiological Studies 65
1.9.2 Morphological Studies 67
1.9.3 Clinical Studies 67
1.10 Contrast Sensitivity 69
1.10.1 Amblyopia and Contrast Sensitivity Function 72
1.10.2 Binocular Interactions in Amblyopia 75
2.0 Methods 76
2.1 Subjective Refraction 76
2.2 Retinoscopy 77
2.2.1 Confirmation ofR efraction 77
2.3 Assessment of Uniocular Fixation Patterns 78
2.4 Assessment of the State of BSV in Heterophoria
and Heterotropia 79
2.4.1 The Cover Test 80
2.4.1.1 The Cover/Uncover Test 80
2.4.1.2 The Alternate (Alternating) Cover Test 82
2.4.2 Bagolini Striated Lornette 84
2.4.3 Worth's Lights (Macular) 87
2.4.4 The Four Dioptre Prism Reflex Test 88
2.5 Measurement of the Angle of Heterophoria
and Heterotropia 91
2.5.1 The Prism and Cover Test 91
2.5.2 The Simultaneous Prism and Cover Test 91
2.6 Measurement of the Amplitude of Accommodation 92
2.7 Measurement of Contrast Sensitivity Function 93
2.7.1 Apparatus 93
2.7.2 Calibration 94
2.7.3 Experimental Procedure 95
III
Contents
2.8 Neutralisation of the Angle of Strabismus in
Squinting Subjects 97
2.9 Control Experiment on Prismatic Correction 98
2.10 Dichoptic Viewing Experiments 99
2.10.1 Apparatus 99
2.10.2 Experimental Procedure/or Normal Subjects
And Simple Anisometropic Amblyopes 101
2.10.3 Strabismic Subjects 104
2.11 Group Composition and Characteristics 105
2.11.1 Selection 105
2.11.2 The Normal Group 105
2.11.3 Simple Anisometropic Amblyopes 106
2.11.4 Micro-esotropic Amblyopes 106
2.11.5 Esotropic Amblyopes with Anomalous BSV 106
2.11.6 Esotropic Amblyopes without BSV 106
2.11. 7 Non-Amblyopic Esotropes without BSV 106
2.11.8 Exotropic Amblyopes without BSV 107
2.11.9 Non-Amblyopic Exotropes without BSV 107
2.12 Statistical Analysis 107
3.0 Results 108
3.1 Investigation of Monocular and Binocular Contrast
Sensitivities 108
3.1.1 The Normal Group 108
3.1.1.1 Ocular Status 109
3.1.1.2 Contrast Sensitivity: Individual Data 109
3.1.1.3 Contrast Sensitivity: Group Data 110
3.1.2 Simple Anisometropic Amblyopes 115
3.1.2.1 Ocular Status 115
3.1.2.2 Contrast Sensitivity: Individual Data 115
3.1.2.3 Contrast Sensitivity: Group Data 117
3.1.3 Micro-esotropic Amblyopes 122
3.1.3.1 Ocular Status 122
3.1.3.2 Contrast Sensitivity: Individual Data 123
iv
Contents
3.1.3.3 Contrast Sensitivity: Group Data 124
3.1.4 Esotropic Amhlyopes with Anomalous BSV 128
3.1.4.1 Ocular Status 128
3.1.4.2 Contrast Sensitivity: Individual Data 129
3.1.5 Esotropic Amhlyopes without BSV 134
3.1.5.1 Ocular Status 134
3.1.5.2 Contrast Sensitivity: Individual Data 135
3.1.5.3 Contrast Sensitivity: Group Data 136
3.1.6 Non-Amhlyopic Esotropes without BSV 139
3.1.6.1 Ocular Status 139
3.1.6.2 Contrast Sensitivity: Individual Data 139
3.1.6.3 Contrast Sensitivity: Group Data 141
3.1. 7 Exotropic Amhlyopes without BSV 145
3.1.7.1 Ocular Status 145
3.1. 7. 2 Contrast Sensitivity: Individual Data 145
Subject 1 146
Subject 2 147
3.1.8 Non-Amhlyopic Exotropes without BSV 150
3.1.8.1 Ocular Status 150
3.1.8.2 Contrast Sensitivity: Individual Data 150
Subject 1 150
Subject 2 152
3.1.9 Summary 155
3.2 Neutralisation of the Angle of Strabismus 157
3.2.1 Micro-esotropic Amhlyopes 157
3.2.1.1 Contrast Sensitivity: Individual Data 157
3.2.1.2 Contrast Sensitivity: Group Data 158
3.2.2 Esotropic Amhlyopes with Anomalous BSV 162
3.2.2.1 Contrast Sensitivity: Individual Data 162
3.2.3 Esotropic Amhlyopes without BSV 167
3.2.3.1 Contrast Sensitivity: Individual Data 167
3.2.3.2 Contrast Sensitivity: Group Data 169
3.2.4 Non-Amhlyopic Esotropes without BSV 172
v
Contents
3.2.4.1 Contrast Sensitivity: Individual Data 172
3.2.4.2 Contrast Sensitivity: Group Data 173
3.2.5 Exotropic Amblyopes without BSV 176
3.2.5.1 Contrast Sensitivity: Individual Data 176
Subject 1 176
Subject 2 179
3.2.6 Non-Amblyopic Exotropes without BSV 182
3.2.6.1 Contrast Sensitivity: Individual Data 183
Subject 1 183
Subject 2 185
3.2.7 Summary 189
3.3 Control Prism Experiments 191
3.3.1 Contrast Sensitivity: Individual Data 192
3.3.2 Contrast Sensitivity: Group Data 196
3.4 Dichoptic Viewing Experiments 199
3.4.1 The Normal Group 200
3.4.1.1 Contrast Sensitivity: Individual Data 201
Subject 1 201
3.4.1.2 Contrast Sensitivity: Group Data 203
3.4.2 Simple Anisometropic Amblyopes 204
3.4.2.1 Contrast Sensitivity: Individual Data 205
Subject 1 205
Subject 2 206
3.4.3 Strabismic Subjects 208
3.4.3.1 Micro-esotropic Amhlyopes 208
Contrast Sensitivity: Individual Data 208
Subject 1 209
Subject 5 210
3.4.3.2 Esotropic Amhlyopes without BSV 212
Contrast Sensitivity: Individual Data 212
Subject 3 212
Subject 4 214
Subject 5 215
3.4.4 Summary 216
vi
Contents
4.0 Discussion 219
4.1 Monocular Contrast Sensitivities 219
4.1.1 The Normal Group 219
4.1.2 The Reclassified Amhlyopic Group 224
4.1.2.1 Micro-esotropic Amhlyopes 226
with Anomalous BSV
4.1.2.2 Esotropic Amhlyopes with Anomalous 226
BSV
4.1.2.3 Esotropic Amhlyopes without BSV 228
4.1.2.4 Exotropic Amhlyopes without BSV 228
4.1.3 The Reclassified Non-Amhlyopic Group 229
4.1.3.1 Non-Amhlyopic Esotropes without BSV 229
4.2 Binocular Contrast Sensitivity in the Reclassified
Groups with BSV 231
4.2.1 The Normal Group 231
4.2.2 Simple Anisometropic Amhlyopes 231
4.2.3 Esotropic Amhlyopes with Anomalous BSV 232
4.2.2 Binocular Contrast Sensitivity in the Reclassified
Groups without BSV
4.2.2.1 Esotropic Amhlyopes without BSV 235
4.2.2.2 Non-Amhlyopic Esotropes without BSV 235
4.2.2.3 Exotropic Amhlyopes without BSV 235
4.2.3 Summary 237
4.3 Neutralisation of the Angle of Strabismus 239
4.3.1 Esotropes 239
4.3.2 Prismatic Degradation 242
4.3.3 Exotropes 243
4.4 Dichoptic Viewing 244
4.5 Visual Deficit in Amblyopia 248
4.5.1 Dichoptic Masking 248
4.5.2 Binocular Rivalry 249
vii
Contents
4.6 Proposed Model 250
4.6.1 The Normal Group 251
4.6.2 Simple Anisometropic Amblyopes 253
4.6.3 The Strabismic Groups 254
4.6.3.1 Esotropic Amblyopes with BSV 254
4.6.3.2 Esotropic Amblyopes without BSV 256
4.6.3.3 Bifoveal Stimulation 257
-Esotropic Amblyopes with Anomalous 258
BSV
-Esotropic Amblyopes without BSV 259
- Normals and Simple Anisometropic 261
Amblyopes
4.7 Summary 264
4.8 Conclusions 265
5.0 References 266
6.0 Appendices 288
viii