Prognostic factors for successful surgical outcome with preoperative prism adaptation test in patients with superior oblique palsy

Purpose: This study evaluated the surgical outcome of patients managed with preoperative prism adaptation test (PAT) and investigated prognostic factors for successful motor alignment in adult patients with superior oblique palsy. Methods: Prospective study of preoperative PAT was performed. Fifty-seven patients with superior oblique palsy, aged 16 to 81 years, participated in this study. Patients were assigned to surgery with the target angle based on either the original angle or the prism compensated angle. When the amount of neutralizing prism exceeded 4Δ or more compared to the original angle of deviation, the patient was defined as having prism compensation, and the target angle for surgery was based on the amount of neutralizing prism. The motor success rate was compared between the 2 groups at the 3-month postoperative follow-up. Results: The prism responders group showed a superior outcome compared to that of the prism non-responders group (77% successful outcome compared with 46%, p = 0.0397). The presence of prism compensation and the amount of vertical deviation were significant prognostic factors for successful motor alignment. Conclusion: Preoperative PAT is a useful prognostic indicator of successful surgical outcome in patients with superior oblique palsy.