Measurement of the Angle of Exodeviation With Polarized Glasses in Intermittent Exotropia

Purpose: The purpose of this study was to investigate if the angle of deviation with Polarized glasses is effective for measuring maximal angles in patients with intermittent exotropia (IXT). Design: Prospective cross-sectional study. Methods: This study was conducted on patients with >10 prism diopters (PD) of basic-type IXT at distance and near. Three consecutive, different methods for measurement of the angle of deviation were used: alternate prism cover test (ACT), ACT with Polarized glasses (Polaroid test), and ACT after 1 hour of monocular occlusion (occlusion test). Comparison of the 3 methods of measurement was conducted using the Friedman repeated ANOVA and Wilcoxon signed rank test. Results: A total of 60 patients were included in this study. Thirty (50%) patients were male. Mean age was 8.7 ± 5.1 years (range, 4-37 years) and measurements by ACT at distance and near were 25.2 ± 8.0 PD and 25.4 ± 8.2 PD, respectively. Angles of Polaroid and occlusion tests (29.0 ± 8.6 PD vs 30.6 ± 8.1 PD) were significantly increased compared to that of ACT at distance (P <.01), and there was no significant change between angles of Polaroid and occlusion tests at distance (P =.06). However, there was no significant change between angles of ACT and Polaroid tests (25.4 ± 8.2 PD vs 26.9 ± 8.1 PD) at near (P =.07). Conclusion: The angle of deviation with Polarized glasses at distance increased and was comparable to that after the monocular occlusion test. The angle of exodeviation with Polarized glasses may be an easy, simple and effective alternative to measurement of maximum angle of deviation in IXT.