A-pattern Strabismus
Eye misalignment where the horizontal deviation increases when looking up and decreases when looking down, forming an 'A' shape.
Full Definition
A-pattern strabismus describes a specific type of eye misalignment characterized by convergence of the visual axes in upgaze and divergence in downgaze, creating a pattern resembling the letter 'A' when the patient's eye positions are mapped. This pattern is often associated with inferior oblique muscle underaction or superior oblique muscle overaction. The condition requires careful measurement of eye alignment in different gaze positions and may necessitate specialized surgical approaches targeting the oblique muscles or horizontal rectus muscle transposition procedures. Diagnosis requires at least 10 prism diopters difference between upgaze and downgaze measurements.
Usage
Usage note: Always capitalize 'A' in 'A-pattern' and include the hyphen; specify measurements in both upgaze and downgaze.
In Context
- "The patient exhibits A-pattern strabismus with 15 prism diopters of esotropia in upgaze and 5 prism diopters in downgaze." — Strabismus evaluation report
- "Surgical planning for A-pattern strabismus must address both the horizontal misalignment and the pattern component." — Pre-operative consultation note