Changes in Angle of Exodeviation According to Distance after Monocular Occlusion in Intermittent Exotropia

Abstract

Purpose: This study investigated changes in the angle of exodeviation at different distances and the characteristics of a group that showed an increased angle following monocular occlusion in intermittent exotropia.Methods: In all, 102 patients diagnosed with basic intermittent exotropia were enrolled. The deviation angle was measured using a mirror at 33 cm, 3 m, 6 m, 12 m, and 6 m. Moreover, the deviation was measured at 33 cm and 3 m after patching the non-dominant eye for 1 hour. Patients with a higher deviation angle at 33 cm after occlusion were categorized as the ‘increased group’, whereas those with lower deviation angles were classified as the ‘stationary group’.Results: There was a male-to-female ratio of 46:56 and an average age at surgery of 9.23 years. No significant differences were observed in deviation measurements taken at 3, 6, 12, and 6 m using a mirror. However, after occlusion, there was a significant increase in deviation at 33 cm (p < 0.01). The average log value of near stereoacuity was 1.96 ± 0.35 in the increased group and 2.16 ± 0.41 in the stationary group. The group with an increased near deviation after occlusion demonstrated a significantly improved near stereoacuity (p = 0.01) and an increased proportion of good results in the near Worth 4 dot test (p = 0.03).Conclusions: Preoperative measurement of maximum deviation after 1 hour of monocular occlusion can help reduce recurrence and insufficient correction, particularly in patients with good fusional ability.