Surgical outcome after prism adaptation for esotropia with a distance-near disparity.

INTRODUCTION: Prism adaptation for patients with esotropia and a distance-near disparity is controversial. The purpose of this study was to evaluate the surgical outcome for patients who underwent prism adaptation for esotropia with a distance-near disparity and determine whether both preoperative sensory and motor fusion are necessary to determine surgical success. METHODS: The medical records of 65 prism-adapted patients with a distance-near disparity of 9 PD or more were reviewed. Prism responders had a fusion response to near Worth 4-dot test and a deviation with prisms of 8 PD or less of esotropia at near, and 5 PD or less of exotropia at distance, or both. The same criteria were used postoperatively to assess a successful surgical outcome. Patients were operated for the near angle or greater than the near angle. RESULTS: Fifty-eight of 65 patients (89%) demonstrated fusion with prisms. Twenty of 65 patients (31%) had increased deviations that were greater than their original near angle (prism builders). Eleven percent (7 of 65) had no fusion. Postoperatively, 88% (51 of 58) of all fusers, 95% (18 of 19) of prism builders, and 71% (5 of 7) of nonfusers had a good surgical outcome of 8 PD or less of esotropia at near, 5 PD or less of exotropia at distance, or both. CONCLUSIONS: Prism response for distance-near disparity esotropia is a good indicator of postoperative outcome. Responders to prism adaptation had a better surgical outcome compared with nonresponders. In particular, prism adaptation aids in detecting those patients who will benefit from larger amounts of surgical correction.