Extraocular Muscle Transplantation for Primary Treatment of Large-Angle Exotropia

To report the feasibility and outcomes of muscle transplantation combined with a unilateral recession-resection procedure for primary large-angle [≥60 Prism Diopters (PD)] exotropia.

We retrospectively reviewed medical records of patients from three tertiary eye-care institutes who underwent unilateral recess-resect with muscle transplantation for primary treatment of large angle exotropia between August 2017 and July 2020. Motor and restorative success were defined as alignment ≤10PD of orthotropia and ≤12PD of manifest deviation, respectively, at the final follow-up. Patients with at least 3 months of follow-up were included.

Ten patients; six males and four females (median age 26 years) met the study criteria. The median follow-up was 12.89 months. The median preoperative exotropia reduced from 65PD (60 to 90PD) to 10PD (0 to 25PD) at final follow-up (p = .0019). The median correction obtained for the entire procedure (recession + resection + muscle transplantation) was 3.05 (1.8 to 4.3) PD/mm. Motor and restorative success was achieved in 60% and 70% of the patients, respectively. The median abduction limitation was -1 (0 to -1) at the final follow-up and there were no palpebral fissure changes beyond 6 weeks postoperatively.

Unilateral muscle transplantation combined with the recession-resection procedure could be a useful alternative for the management of large-angle exotropia.