Aim To evaluate the prevalence of lateral incomitance (LI) and its association with surgical outcome in intermittent exotropia.

Methods We retrospectively surveyed patients who had been followed up for 18 months or more after surgery for intermittent exotropia conducted from 1 September 2008 to 31 December 2010. Preoperative significant LI (preLI+) was defined as a decrease of >5 prism dioptres (PD) in exodeviation of distant gaze at lateral gaze. Postoperative significant LI (postLI+) was defined as a difference of >5 PD between distant and lateral gaze. Gender, age at surgery, binocular spherical equivalent, preoperative angle of deviation, type of intermittent exotropia, type of surgery, and stereopsis were investigated together with associations with LI and surgical results. Surgical results were analysed using data from a postoperative period of at least 18 months.

Results Of 155 patients, 63 (40.6%) had preLI+. Surgical failure including consecutive esotropia was not associated with preLI+ (p=0.140). In subgroup analysis, bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession (ULR) procedures did not induce significant LI, but non-operated eyes with ULR showed reduced LI after surgery.

Conclusions Surgical outcomes in ULR and BLR for intermittent exotropia correction showed no association with preLI+. The prevalences of significant LI were unchanged after surgery in both groups.