To examine the surgical results of large-angle exodeviations over 30 prism diopters (PD) and correlation factors influencing surgical outcomes.

The authors retrospectively examined 63 patients with an exodeviation greater than 30 PD. All patients were examined for at least six months after the operation. Near and far deviation angles, age at operation, operation method, and alignment at postoperative one week, one month, three months and six months were analyzed as factors influencing the surgical outcome.

The preoperative deviation was 35 to 40 PD (38.1%) in most cases. Forty-five patients underwent bilateral lateral rectus recession, 16 patients underwent unilateral medial rectus resection and lateral rectus recession, and two patients underwent surgery on three different muscles. Success was defined as sustained alignment from esotropia 10 PD to exotropia 10 PD. The success rate was 79.4% at the first week, 77.8% at one month, 73.0% at three months, and 68.3% at six months postoperatively. In particular, the success rate was significantly lower at six months postoperatively in the group with exotropia greater than 45 PD (36.4%). The patients with esotropia on the first postoperative week showed a significantly high success rate (86.6%); however, neither the age at operation nor the operation method affected the surgical results.

Large-angle exodeviations can be successfully approached with a single operation, with a success rate of 68.3% at six months postoperatively. Esotropia of less than 10 PD at the first postoperative week shows the most ideal surgical results. For patients having exodeviations greater than 45 PD, the success rate will decrease over time. Therefore, surgeons should carefully plan for large-angle exodeviation surgery.