Usefulness of the preoperative prism adaptation test in patients with intermittent exotropia

Abstract

Purpose: To investigate whether the preoperative prism adaptation test is useful in patients with intermittent exotropia.

Methods: Sixty-five consecutive patients with basic-type intermittent exotropia <40 prism diopters (PD) comprised the study population in this prospective study. Patients were divided into two groups based on the results of the prism adaptation test. Patients with a negative response comprised group 1 and patients with a positive response comprised group 2. Group 1 patients (n=26) underwent surgery according to the original angle, and group 2 patients (n=27) underwent surgery in accordance with the change in the angle of deviation with prisms.

Results: Satisfactory motor alignment (+/- 5 PD of orthophoria) was achieved in 14 (53.8%) group 1 patients and 24 (88.8%) group 2 patients (P=.01). Mean residual deviation was 9.8 PD in group 1 and 4.5 PD in group 2 (P < or = .05).

Conclusion: The prism adaptation test may be helpful in achieving a favorable surgical outcome in intermittent exotropia.