 There is poor agreement as to which type of surgery is most effective for the correction of IXT and the debate has long been related to differentiation between IXT sub-types. Based on distance-near angle disparity, IXT sub-types are classified as: 1 basic similar magnitude of misalignment at distance and near; 2 true divergence excess larger at distance; 3 pseudo divergence excess initially larger at distance, but near angle increases following occlusion or with addition of plus lenses at near; 4 convergence insufficiency larger at near. Basic and pseudo divergence excess appear to be the most common of the sub-types, and are also the types for which there is most disagreement regarding the optimum surgical approach. The two most common procedures are bilateral lateral rectus recession BLRrec and unilateral lateral rectus recession combined with a medial rectus resection in the same eye RR. Traditionally, BLRrec has been advocated where there is a larger distance angle, and RR where there is a similar angle at distance and near. A survey of American strabismus surgeons published in 1990 found that the majority performed BLRrec for both basic and divergence excess types. Similarly, we found by polling our investigator group that the majority still perform a BLRrec for basic type IXT. Nevertheless, controversy still exists as to which of these surgical approaches is superior. Advocates of the BLRrec procedure tend to hold that surgery should be based purely on the distance angle of deviation. Proponents of RR surgery suggest resection of the medial rectus best addresses the exodeviation at near. 