Virtual Reality-Based Vision Therapy for Intermittent Exotropia: A Randomized Clinical Trial.

Abstract

Intermittent exotropia (IXT), the most common childhood divergent strabismus, disrupts binocular vision and psychosocial function. To assess the efficacy and safety of virtual reality-based vision therapy (VRVT) in children with IXT. This randomized clinical trial consists of a 12-week treatment phase (completed) and a 12-month follow-up phase (ongoing). The treatment phase was conducted from July 1, 2023, to November 17, 2024, in 3 tertiary hospitals in China. Eligible participants were children aged 6 to 18 years with previously untreated IXT, an exodeviation magnitude of 10 to 30 prism diopters at distance, an exotropia control score of 1 to 3 at both distance and near, and a cycloplegic spherical equivalent between -6.00 diopters (D) and +0.50 D in both eyes, with an interocular spherical equivalent difference of less than 2.50 D. Participants were randomly assigned in a 1:1 ratio to the intervention group or control group. Participants in the intervention group underwent the home-based VRVT program for 12 weeks. Participants in the control group were observed but received no VRVT intervention. The primary outcome was the change in distance exotropia control score from baseline to week 12. The Mann-Whitney test and Hodges-Lehmann estimator were used for between-group comparisons. Data analysis followed the modified intention-to-treat approach. A total of 177 participants (median [IQR] age, 8 [7-10] years; 95 males [53.7%]) were randomized, of whom 161 were included in the full analysis set. At week 12, the median (IQR) change in distance exotropia control score was -0.33 (-1.00 to 0.00) in the intervention group vs 0.00 (-0.33 to 0.33) in the control group (between-group difference, -0.33; 95% CI, -0.57 to -0.10). Participants with greater than 75% VRVT training adherence had a greater improvement in distance exotropia control score than the control group (between-group difference, -0.71; 95% CI, -1.10 to -0.33). A significant interaction was identified between baseline distance exotropia control score and treatment effect (P for interaction = .01); greater improvement was observed in participants with a baseline score of 2 or higher (between-group difference, -0.67; 95% CI, -1.00 to -0.33), whereas minimal effect was seen in those with a score of 1 (between-group difference, -0.01; 95% CI, -0.23 to 0.20). No intervention-related adverse events were reported. In this randomized clinical trial, the improvement in distance exotropia control over 12 weeks was modest. However, greater benefits were observed in participants with greater than 75% VRVT training adherence, which may indicate clinical value for children able to maintain high training adherence. Chinese Clinical Trial Registry Identifier: ChiCTR2300072912.