Comparison of long-term surgical outcomes of 2-muscle surgery in children with large-angle exotropia: bilateral vs unilateral.

PURPOSE To evaluate the long-term results of 2-muscle surgery in children with primary large-angle exotropia, comparing 10 mm bilateral lateral rectus recession (BLR) with unilateral lateral rectus recession-medial rectus resection (recess/resect). DESIGN Retrospective case series. METHODS Eighty-six children with exotropia of ≥40 prism diopters (PD), who underwent the 10 mm BLR (BLR group) or the unilateral recess/resect procedure (RR group) based on the largest angle measured at distance or near were included. Patients were followed-up for more than 2 years. Final successful alignment rates, stereopsis, and factors related to recurrence and overcorrection were evaluated. RESULTS At the final examination, 29 (60.4%) of 48 patients in the BLR group achieved successful alignment; 16 (33.3%) had recurrence, and 3 (6.3%) had overcorrection. In the RR group, 26 of 38 patients (68.4%) were successfully aligned, 10 (26.3%) had recurrence, and 2 (5.3%) had overcorrection. Successful alignment and recurrence rates were not significantly different in the groups (P = .371 and .640, respectively). The overcorrection rate was significantly higher in the RR group (P = .014) until 2 years after surgery, but this difference was not significant afterward (P = 1.000). In patients with an exodeviation of ≥45 PD, the recess/resect procedure showed higher successful alignment rates at the final examination (P = .006). CONCLUSIONS The long-term successful alignment rate of 2-muscle surgery in children with primary large-angle exotropia was 64%, and the overall surgical outcomes were comparable between the BLR and RR groups. However, in patients with exotropia of ≥45 PD, the unilateral recess/resect procedure resulted in more favorable long-term outcomes.