Comparative Evaluation of Unilateral Recession-Plication Versus Bilateral Three-Muscle Surgery for Large-Angle Exotropia.

Abstract

Purpose: To evaluate and compare unilateral recession-plication versus bilateral three-muscle surgery for large-angle exotropia.

Methods: A prospective interventional non-randomized comparative study was conducted involving 66 patients with large-angle exotropia, with deviation between 50 and 65 prism diopters (PD). Patients were divided into two groups: those who underwent unilateral large lateral rectus (LR) recession (≥8 mm) and medial rectus (MR) plication (>5 mm) (two-muscle group), and those who underwent bilateral LR recession (7.5 to 9 mm each eye) and MR resection (5 mm) in the non-dominant eye (three-muscle group). Patients were administered the Adult Strabismus-20 (AS-20) questionnaire before surgery and at the 3-month follow-up visit.

Results: The mean preoperative deviation for distance in the two-muscle (n = 34) and three-muscle (n = 32) groups was 56.53 ± 5.62 and 54.89 ± 5.83 PD, respectively (P = .849). The mean postoperative deviation was 9.29 ± 3.16 PD in the two-muscle group and 8.44 ± 3.54 PD in the three-muscle group at the 6-month postoperative visit (P = .303). A successful motor outcome was observed in 25 of 34 patients (73.53%) in the two-muscle group and 24 of 32 patients (75%) in the three-muscle group (P = 1.00). Both groups showed a statistically significant improvement in AS-20 scores. There was a comparable low-grade limitation of ocular motility in both groups.

Conclusions: In patients with large-angle exotropia up to 65 PD, two-muscle surgery achieved acceptable ocular alignment with no statistically significant difference in motor outcomes or motility limitations compared to traditional three-muscle surgery.