Main description:

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.

Contents:

I Introduction.- I. Definition. Classification.- II. Goals of treatment.- III. Goals and possibilities of treatment in the different forms of convergent comitant esotropia.- A. Early esotropia.- B. Late esotropia.- 1. Accommodative esotropia.- 2. Acquired non-accommodative esotropia.- C. Microstrabismus.- II History of Strabismus Treatment.- I. Introduction.- II. Surgical procedures for convergent squint.- A. Interventions on the medial rectus muscle.- 1. Myotomy and tenotomy.- 2. Partial tenotomy.- 3. Controlled (bridled) tenotomy.- 4. Recession.- 5. Muscle lengthening.- 6. Faden-Operation.- 7. Other weakening procedures.- B. Interventions on the lateral rectus muscle.- 1. Simple advancement.- 2. Resection.- 3. Tucking of the lateral rectus muscle.- 4. Malbran's screwlike twisting.- C. Interventions for A and V Phenomena.- 1. Interventions on the horizontal recti.- 2. Interventions on the vertical recti.- 3. Interventions on the oblique muscles.- D. Combined surgical procedures.- III. Non-surgical procedures.- A. Optical corrections.- 1. Positive glasses.- 2. Bifocals.- 3. Prisms.- B. Other procedures.- 1. Orthoptics.- 2. Penalisation.- 3. Miotics.- III Normal Binocular Vision.- I. Introduction.- II. Psychophysics of spatial vision.- A. The horopter. Binocular vision without depth.- B. Depth perception. Range of stereoscopic vision.- C. Cyclopean localization.- D. Local and global stereoscopic vision.- III. Neuroanatomy of binocular vision.- IV. Neurophysiology of binocular vision.- V. Motor aspects of binocular vision.- VI. Diagrammatic representation of binocular vision.- IV Neuromechanics of the Human Peripheral Oculomotor System.- I. Mechanical elements of the peripheral oculomotor system.- II. Fixation.- III. Saccades.- IV. Smooth pursuit.- V. Vergences.- V Symptomatology.- I. Definitions and terminology.- A. Definition.- B. Classification.- II. Sensory anomalies I: suppression and amblyopia.- A. Suppression.- B. Amblyopia.- III. Sensory anomalies II: anomalous binocular vision.- A. Anomalous correspondence.- B. Psychophysics.- C. Neuroanatomy and neurophysiology.- D. Motor aspects.- E. Diagrammatic representation of anomalous binocular vision.- IV. Sensory anomalies III: diplopia.- A. Transient diplopia.- B. Persistent diplopia.- V. Prevalence of convergent strabismus.- VI. Age of onset of convergent strabismus.- VII. Strabismus and convergence.- A. Types of convergence.- B. Accommodative aspects.- C. Tonic and spastic convergence.- VIII. Nystagmus and related disturbances.- A. Occlusion nystagmus.- B. Occlusion hypertropia.- IX. Incomitance in convergent strabismus.- X. Clinical syndromes.- A. Strabismus, early onset.- B. Strabismus, late onset.- C. Microstrabismus.- XI. Pathogenesis of convergent strabismus.- A. Symptom or disease?.- B. Heredity.- C. Theories concerning squint.- D. Inadequacy of the theories.- VI Examination Methods.- I. History.- II. Inspection.- Basic examination position.- A. Torticollis.- B. The eyelid and palpebral fissures.- C. The pupils.- D. Nystagmus.- III. The corneal reflections.- IV. The covertest.- A. Type I. The monolateral covertest.- B. Type II. The alternating covertest.- V. Prisms examinations.- A. Horizontal prism test.- B. Vertical prism test.- C. Prism bar.- VI. Examination of ocular movements.- A. Versions.- 1. Horizontal movements.- 2. Vertical movements.- 3. Diagonal movements.- B. Ductions.- C. The Bielschowsky test.- D. Convergence.- 1. The sliding convergence.- 2. The sudden convergence.- VII. Cycloplegia.- VIII. Ocular media and fundus.- IX. Visual acuity test.- X. Measurement of the angle of deviation.- A. Estimation of the deviation.- 1. Non-foveal fixation (corneal reflection).- - Maddox scale.- - Krimsky test.- - The synopthophore.- 2. Foveal fixation : Hirschberg test.- B. Measurement of the deviation.- 1. The objective methods.- a. the manifest angle.- - Maddox scale.- - prism and simultaneous cover.- - the Synoptophore.- b. the maximum angle.- - Maddox scale.- - prism and alternating cover.- - the Synoptophore.- 2. The subjective methods.- - the Synoptophore.- - dark red glass and Maddox scale.- XI. The sensorial status.- Children under 4 years.- Children above 4 years.- A. Foveal fixation.- 1. Less-dissociating examinations.- 1.1 Striated glasses.- 1.2 Phasendifferenzhaploskop.- 1.3 Diplopia.- - red glass.- - vertical prism.- - prism compensation.- 1.4 Fusion and stereopsis.- 2. Dissociating examinations.- 2.1 the Worth four dot test.- 2.2 the Synoptophore.- 2.2.1 real objects.- 2.2.2 entoptic phenomena.- 2.3 Dark red glass and after-image.- B. Non-foveal fixation.- 1. the foveo-foveolar test.- 2. the Synoptophore : Haidinger and after-image.- XII. Preoperative examinations.- A. The prism compensation test.- B. Tests to forecast post-operative diplopia.- VII Amblyopia.- I. Introduction.- II. Sensoric aspects.- A. Psychophysics.- B. Electrophysiology.- C. Neuroanatomy.- III. Motoric aspects.- IV. Conclusion.- V. The diagnosis of amblyopia.- A. The "Ammann" effect.- B. The "Trennschwierigkeit" or crowding effect.- C. The visual acuity.- D. The contrast sensitivity.- E. The VECP.- VI. The treatment of amblyopia.- VIII Conservative treatment.- I. Basic treatments.- A. Optical treatment.- B. Occlusion.- C. Penalisation.- II. Treatment adapted to the different strabismus groups.- A. Early onset strabismus.- B. Late onset strabismus.- 1. Pure accommodative strabismus.- 2. Atypical accommodative strabismus.- 3. Partially accommodative strabismus.- C. Microstrabismus.- III. Complementary treatment.- A. Prism treatment.- B. Orthoptic treatment.- IV. Postoperative conservative treatment.- IX Surgical Management of Esotropia.- Surgical techniques.- A. General directives.- B. Specific directives.- 1. Strengthening procedures.- Strengthening of a rectus muscle.- Strengthening of an oblique muscle.- 2. Weakening procedures.- Weakening of a rectus muscle.- Weakening of an oblique muscle.- 3. Transpositioning procedures.- Transpositioning of a rectus muscle.- Transpositioning of an oblique muscle.- Surgical effects.- 1. Surgery of the horizontal rectus muscles.- 2. Surgery of the vertical rectus muscles.- 3. Surgery of the oblique muscles.- Surgical indications.- I. Conventional surgery.- A. General directives.- B. Specific directives.- 1. Primary surgery.- Treatment of horizontal deviations.- Treatment of diagonal deviations.- Treatment of torsional deviations.- Treatment of vertical deviations.- 2. Secondary surgery.- a. Undercorrections.- b. Overcorrections.- II. Simultaneous horizontal and cyclovertical surgery.- A. General directives.- B. Specific directives.- 1. Primary surgery.- Treatment of horizontal deviations.- Treatment of diagonal deviations.- Treatment of vertical deviations.- 2. Secondary surgery.- a. Undercorrections.- Treatment of horizontal undercorrections.- Treatment of diagonal undercorrections.- Treatment of vertical undercorrections.- b. Overcorrections.- Treatment of horizontal overcorrections.- Treatment of diagonal overcorrections.- Treatment of vertical overcorrections.- Surgical complications.- 1. Conjunctiva and capsular tissue.- 2. Muscles.- 3. Bulbus.- 4. Eyelids.- 5. Palpebral fissure.- 6. Postoperative diplopia.- 7. Anaesthesia.