Pseudo inferior oblique overaction associated with Y and V patterns.

Abstract

Nine patients with Y or V patterns are presented. All patients had an eye movement pattern that resembled but was distinctly different from bilateral inferior oblique overaction. Despite marked abduction of either eye when it elevated in adduction, no patient had elevation of the adducting eye on direct side gaze, superior oblique underaction, a forced head tilt difference, or torsion. Weakening of the inferior obliques in four of these patients, either with surgery or temporary chemodenervation, did not eliminate this pseudo inferior oblique overaction movement. Recession and elevation of the lateral recti normalized the ocular rotations in three patients. The author proposes that these patients represent a variant of the co-contraction syndrome.