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A & V PATTERNS

A horizontal deviation may be vertically incomitant, ie, the deviation is different in upgaze versus downgaze (A or V pattern). An A pattern shows more esodeviation or less exodeviation in upgaze compared to downgaze. A V pattern shows less esodeviation or more exodeviation in upgaze compared to downgaze. An A pattern is diagnostically significant when greater than 10^Δ and a V pattern when greater than 15^Δ. These patterns are frequently associated with overaction of the oblique muscles, inferior obliques for V patterns and superior obliques for A patterns.

When surgically treating an A or V pattern, oblique muscle overaction must be treated if present. If little or no oblique overaction exists, vertical offsets of one tendon width of the horizontal muscles are utilized to collapse the pattern. The insertions of the medial rectus muscles are displaced toward the narrow end of the pattern (in V esotropia, recessed medial rectus muscles are moved down), and lateral rectus muscles are displaced toward the open end (in V exotropia, the insertions of the recessed lateral rectus muscles are moved up).

10.1036/1535-8860.ch12

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