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Ophthalmology
A-V Patterns
Built from Strabismus Simplified, Second Edition
What’s inside
7 sections · 66 slides
Overview
- Scope of this presentation
Definition and classification
- Vertically incomitant comitant horizontal deviations
- The V pattern
- The A pattern
- V pattern exotropia
- A pattern esotropia
- The four main patterns
- Additional patterns beyond A and V
- Alphabetic pattern nomenclature
- Patterns with and without oblique muscle overaction
- V-exotropia with bilateral inferior oblique overaction
- V-exotropia without inferior oblique overaction
- V-esotropia with bilateral inferior oblique overaction
- A-esotropia with bilateral superior oblique overaction
- A-esotropia without superior oblique overaction
Prevalence
- Prevalence of A and V patterns
- Relative frequency of the patterns
Etiology
- Etiological schools of A-V patterns
- Horizontal school of Urist
- Horizontal school: pattern and causative horizontal rectus
- Surgical corollary of the horizontal school
- Vertical school of Brown
- The cyclovertical school
- Cyclovertical mechanism of the V pattern
- Overacting and underacting muscles and the pattern produced
- Oblique dysfunction in clinical practice
- Brown's syndrome as a mimic
- Structural factors: skull and orbital variation
- Trochlear position and relative oblique strength
- Anomalies of muscle insertions
- Torsional consequence of vertical vectors
- Vector forces on vertical shifting of the horizontal recti
- Surgical corollary of the insertional school
Diagnosis
- Gaze positions for measurement
- Prism dioptre thresholds for significance
- Reproducible quantification of gaze position
- Fundus evaluation for torsional change
- Compensatory head postures
Treatment
- Principles of management
- Surgical decision by oblique muscle status
- Horizontal rectus options when obliques are normal
- Determining the amount of surgery
- The rule of thumb for vertical shifting
- Direction of shift by pattern
- Procedures undertaken commonly by pattern
- Procedures undertaken commonly by pattern (continued)
- Slanting recession and resection
- Graded weakening of the inferior oblique
- Graded inferior oblique weakening procedures
- Weakening procedures for superior oblique overaction
- Pure V pattern before surgery
- Pure V pattern after inferior oblique recession and anteropositioning
- A pattern exotropia with bilateral superior oblique overaction
- A pattern exotropia after posterior tenectomy of the superior oblique
- Horizontal shifting of the vertical recti
Summary and references
- Key points
- Common errors to avoid
- Suggested reading
- Suggested reading (continued)
- Strabismus Simplified