Diagnostic occlusion test for acquired esotropia

Abstract

Objective: To assess the effect of the 45-minute diagnostic occlusion test (DOT) on the measured esodeviation in patients with acquired esotropia.

Methods: After the routine ophthalmic examination, 67 patients with acquired esotropia were randomly assigned to either the patch group (37 subjects) or the control group (30 subjects). For both groups the mean distance and near deviations before and after 45 minutes were compared.

Results: The mean pre- and post-DOT measurement at distant target for the patch group was an esodeviation of 6.7 ± 7.5 prism diopters (PD) and 13.2 ± 11.7 PD, respectively. The 45-minute DOT induced an average increase of the esotropia of 6.4 ± 5.9 PD in the patch group (p = 0.0001). For the control group, the first and second mean measurement were similar, 9.2 ± 7.6 PD and 9.1 ± 6.5 PD, respectively (p = 0.103). The mean pre- and post-DOT esodeviation at near distance for the patch group were 10.1 ± 10.1 PD and 18.7 ± 13.7 PD (p = 0.001). Following the DOT, >5 PD change was noted in 26 (70.1%) from a near distance target (p = 0.001). For the control group, the mean near first and second measurements were 13.9 PD and 15.0 PD, respectively.

Conclusion: Performing DOT in acquired esodeviations may help to reveal the full deviation and ultimately decrease the risk of surgical undercorrection by eliminating tonic fusional divergence. The DOT can be applied clinically for acquired esotopia to accurately measure the angle of deviation.