Bilateral Lateral Rectus Recession Versus Unilateral Recess-Resect Procedure For Basic Type Exotropia

Abstract

Exodeviation is a manifest outward deviation of the visual axes relative to each other. It may be primary, secondary (associated with poor vision), or consecutive (may follow an ET with time or after surgical correction). According to fusion control, exodeviation could be XT; being present all the time or X (T); ranging according to ease of dissociation, where large X intermittently breaks down to an XT. X (T) can be further classified into three types based on the difference between the distance and near deviation: (1) basic, where the distance and near deviations are similar, within 10 PD and the target angle is the distance deviation. (2) divergence excess (pseudo and true), where the exotropia is larger for distance fixation than near fixation (≥10 PD). True divergence excess is when the divergence excess persists even after prolonged binocular dissociation by monocular patching (i.e., Patch test). Pseudo-divergence excess is when the near deviation increases after the patch test, so the distance and near deviations are similar (3) convergence insufficiency when the near deviation is 10 PD or larger than the distance deviation. If there is no significant distance deviation, with an exodeviation for near, then this is a pure convergence insufficiency.It is more common in teenagers who report asthenopia.