Relationship between motor alignment at postoperative day 1 and at year 1 after symmetric and asymmetric surgery in intermittent exotropia.

PURPOSE To evaluate the relationship between the motor alignment at postoperative day 1 and at year 1 following bilateral lateral rectus recession (BLR, symmetric surgery) and unilateral lateral rectus recession-medial rectus resection (R&R, asymmetric surgery) for the treatment of intermittent exotropia, X(T). METHODS Forty-six patients with basic or pseudo-divergence excess type of X(T) underwent BLR and 57 patients underwent R&R. The motor alignment at postoperative day 1 was classified as overcorrected by 11-20 prism diopters (PD), overcorrected by 1-10 PD, orthotropic, or undercorrected by 1-10 PD of exotropia. RESULTS There was a statistically significant relationship between the alignment at postoperative day 1 and at year 1 following both R&R and BLR surgery (r = 0.74, r = 0.51, respectively, P <.05). Patients overcorrected by 1-20 PD had a significantly higher success rate than those undercorrected by 1-10 PD on postoperative day 1 (P <.05). For R&R, a postoperative day 1 alignment of 1-10 PD resulted in the highest success rate of 73.7%. For BLR, a postoperative day 1 alignment of 11-20 PD showed the highest success rate of 76.9%. There were no significant differences in the success, undercorrection and overcorrection rates between the two surgical procedures after a 1-year postoperative period. CONCLUSIONS The alignment at postoperative day 1 can be a predictive factor of the surgical outcome in X(T). A postoperative day 1 overcorrection of 11-20 PD following BLR surgery and an overcorrection of 1-10 PD following R&R can lead to good results.