Clinical Orthoptics

Fiona J. Rowe is Lecturer in Orthoptics at the University of Liverpool and an Honorary Research Vision Scientist at the Department of Orthoptics and Ophthalmology, Warrington Hospital. Dr Rowe also lectures extensively to trainee and qualified ophthalmologists, ophthalmic nurses, and other members of the multi-disciplinary eye care team.

Preface xi

Acknowledgements xii

List of Figures xiii

List of Tables xvii

Section I 1

1 Extraocular Muscle Anatomy and Innervation 3

Muscle pulleys 3

Ocular muscles 5

Innervation 10

Associated cranial nerves 12

References 15

Further reading 16

2 Binocular Single Vision 17

Worth’s classification 17

Development 17

Retinal correspondence 19

Physiology of stereopsis 20

Fusion 23

Retinal rivalry 24

Suppression 24

Diplopia 25

References 27

Further reading 28

3 Ocular Motility 29

Saccadic system 29

Smooth pursuit system 31

Vergence system 33

Vestibular-ocular response and optokinetic response 35

Brainstem control 37

Muscle sequelae 39

Past-pointing 40

Bell’s phenomenon 41

References 41

Further reading 43

4 Orthoptic Investigative Procedures 45

Visual acuity 45

Cover test 60

Ocular motility 64

Accommodation and convergence 68

Retinal correspondence 73

Fusion 77

Stereopsis 82

Suppression 89

Synoptophore 91

Aniseikonia 97

Fixation 98

Measurement of deviations 99

Hess charts 105

Field of binocular single vision 108

Uniocular field of vision 110

Measurement of torsion 111

Parks-Helveston three-step test 113

Diplopia charts 113

Bielchowsky phenomenon (dark wedge test) 115

Forced duction test 115

Forced generation test 115

Orthoptic exercises 115

References 119

Further reading 124

Section II 129

5 Heterophoria 131

Classification 131

Aetiology 131

Causes of decompensation 132

Esophoria 132

Exophoria 132

Hyperphoria/hypophoria 133

Alternating hyperphoria 133

Alternating hypophoria 133

Cyclophoria 133

Incomitant heterophoria 133

Hemifield slide 133

Investigation of heterophoria 134

Management 135

References 136

Further reading 137

6 Heterotropia 138

Esotropia 138

Factors necessary for development of binocular single vision 139

Constant esotropia with an accommodative element 140

Constant esotropia without an accommodative element 141

Accommodative esotropia 146

Relating to fixation distance 151

Exotropia 155

Hypertropia 168

Hypotropia 168

Cyclotropia 169

Dissociated vertical deviation 170

Dissociated horizontal deviation 172

Quality of life 173

Pseudostrabismus 174

References 175

Further reading 184

7 Microtropia 189

Terminology 189

Classification 190

Investigation 191

Management 194

References 194

Further reading 195

8 Amblyopia and Visual Impairment 197

Classification 197

Aetiology 197

Investigation 198

Management 199

Eccentric fixation 205

Cerebral visual impairment 205

Delayed visual maturation 206

PHACE syndrome 207

References 207

Further reading 212

9 Aphakia 215

Methods of correction 215

Investigation 215

Problems with unilateral aphakia 216

Management 216

References 218

Further reading 219

Section III 221

10 Incomitant Strabismus 223

Aetiology 223

Aid to diagnosis 225

Diplopia 226

Abnormal head posture 227

References 230

Further reading 231

11 A and V Patterns 232

Classification 232

Aetiology 232

Investigation 236

Management 238

References 241

Further reading 243

12 Accommodation and Convergence Disorders 245

Accommodative disorders 245

Presbyopia – physiological 245

Presbyopia – premature (non-physiological) 246

Accommodative insufficiency 247

Accommodative fatigue 248

Accommodative paralysis 248

Accommodative spasm 249

Accommodative inertia 250

Micropsia 251

Macropsia 251

Convergence anomalies 251

Convergence insufficiency 252

Convergence paralysis 254

Convergence spasm 254

Specific learning difficulty 254

References 255

Further reading 257

13 Ptosis and Pupils 259

Ptosis 259

Marcus Gunn jaw-winking syndrome 263

Lid retraction 264

Pupils 264

References 269

Further reading 271

14 Neurogenic Disorders 272

III (third) cranial nerve 272

IV (fourth) cranial nerve 280

VI (sixth) cranial nerve 288

Multiple sclerosis 292

Acquired motor fusion deficiency 293

Non-accidental injury 294

Premature visual impairment 295

Ophthalmoplegia 296

References 300

Further reading 307

15 Mechanical Paralytic Strabismus 310

Congenital cranial dysinnervation disorders 312

Brown’s syndrome 319

Adherence syndrome 324

Moebius syndrome 325

Strabismus fixus syndrome 327

Thyroid eye disease 327

Orbital injuries 333

Blow-out fracture 334

Soft tissue injury 339

Supraorbital fracture 341

Naso-orbital fracture 341

Zygoma fracture 341

Conjunctival shortening syndrome 342

Retinal detachment 342

Cataract 343

Macular translocation surgery 344

References 344

Further reading 350

16 Myogenic Disorders 354

Thyroid eye disease 354

Chronic progressive external ophthalmoplegia 354

Myasthenia gravis 355

Myotonic dystrophy 358

Ocular myositis 358

Kearns–Sayre ophthalmoplegia 359

References 359

Further reading 361

17 Craniofacial Synostoses 362

Plagiocephaly 362

Brachycephaly 362

Scaphocephaly/dolichocephaly 362

Occipital plagiocephaly 362

Apert’s syndrome 363

Craniofrontonasal dysplasia 363

Crouzon’s syndrome 363

Pfeiffer syndrome 363

Saethre–Chotzen syndrome 364

Unicoronal syndrome 364

General signs and symptoms 364

Ocular signs and symptoms 365

Management 365

References 366

Further reading 367

18 Nystagmus 368

Aetiology 368

Classification 368

Investigation 373

Management 375

References 378

Further reading 380

19 Supranuclear and Internuclear Disorders 382

Saccadic movement disorders 382

Smooth pursuit movement disorders 384

Vergence movement disorders 385

Gaze palsy 386

Optokinetic movement disorders 394

Vestibular movement disorders 395

Brainstem syndromes 395

Skew deviation 397

Ocular tilt reaction 398

Ocular investigation 398

Management options 400

References 401

Further reading 405

Section IV Appendices 407

Diagnostic Aids 409

Abbreviations of Orthoptic Terms 418

Diagrammatic Recording of Ocular Motility 424

Diagrammatic Recording of Nystagmus 426

Glossary 428

Case Reports 441

Index 459