Three-muscle surgery for very large-angle constant exotropia

PurposeTo report the outcomes of surgery on three horizontal muscles for very large-angle constant exotropia.MethodsIn this prospective case series, consecutive adult patients with primary constant exotropia with angles ≥120Δ underwent strabismus surgery on three horizontal muscles. Surgery consisted of lateral rectus recession of 10–15 mm on the fixing eye in addition to lateral rectus recession of 9–13 mm and medial rectus resection of 6.5–9 mm on the nonfixing eye. The mean follow-up period was >6 months. Success was defined as horizontal eso- or exodeviations of ≤10Δ.ResultsA total of 23 patients were included. The mean age at surgery was 30.4 ± 9.3 years (range, 16-52). The mean preoperative near exodeviation was 128Δ ± 9.8Δ; the mean preoperative distance exodeviation, 130Δ ± 10.4Δ. The mean follow-up period was 8.1 ± 1.4 months. At the last follow-up, 19 of the 23 cases (83%) were successfully aligned. At final follow-up examination, the mean postoperative exodeviation was 5Δ ± 4.2Δ (near) and 5Δ ± 4.3Δ (distance); no patient had diplopia on lateral gazes.ConclusionsIn this patient cohort, surgery on three-muscle surgery for very large-angle exotropia successfully restored alignment in primary gaze in over 80% of cases without inducing symptomatic abduction deficits.