Overminus Lens Therapy for Children 3 to 10 Years of Age with Intermittent Exotropia A Randomized Clinical Trial

This randomized clinical trial evaluates whether wearing followed by weaning off overminus spectacles improves distance control in children 3 to 10 years of age with intermittent exotropia. Question Does overminus lens therapy improve distance control in children with intermittent exotropia? Findings This randomized clinical trial found that mean distance exotropia control was significantly better among 386 children aged 3 to 10 years treated with overminus spectacles vs nonoverminus spectacles for 12 months; however, after weaning off overminus spectacles, there was little or no difference in distance control between groups. Myopic shift was approximately one-third diopter greater in the overminus than in the nonoverminus group. Meaning Overminus lens therapy improved distance exotropia control in children 3 to 10 years of age but was associated with greater myopic shift, and the improved control did not persist after overminus treatment was discontinued. Importance This is the first large-scale randomized clinical trial evaluating the effectiveness and safety of overminus spectacle therapy for treatment of intermittent exotropia (IXT). Objective To evaluate the effectiveness of overminus spectacles to improve distance IXT control. Design, Setting, and Participants This randomized clinical trial conducted at 56 clinical sites between January 2017 and January 2019 associated with the Pediatric Eye Disease Investigator Group enrolled 386 children aged 3 to 10 years with IXT, a mean distance control score of 2 or worse, and a refractive error between 1.00 and -6.00 diopters (D). Data analysis was performed from February to December 2020. Interventions Participants were randomly assigned to overminus spectacle therapy (-2.50 D for 12 months, then -1.25 D for 3 months, followed by nonoverminus spectacles for 3 months) or to nonoverminus spectacle use. Main Outcomes and Measures Primary and secondary outcomes were the mean distance IXT control scores of participants examined after 12 months of treatment (primary outcome) and at 18 months (3 months after treatment ended) assessed by an examiner masked to treatment group. Change in refractive error from baseline to 12 months was compared between groups. Analyses were performed using the intention-to-treat population. Results The mean (SD) age of 196 participants randomized to overminus therapy and 190 participants randomized to nonoverminus treatment was 6.3 (2.1) years, and 226 (59%) were female. Mean distance control at 12 months was better in participants treated with overminus spectacles than with nonoverminus spectacles (1.8 vs 2.8 points; adjusted difference, -0.8; 95% CI, -1.0 to -0.5; P < .001). At 18 months, there was little or no difference in mean distance control between overminus and nonoverminus groups (2.4 vs 2.7 points; adjusted difference, -0.2; 95% CI, -0.5 to 0.04; P = .09). Myopic shift from baseline to 12 months was greater in the overminus than the nonoverminus group (-0.42 D vs -0.04 D; adjusted difference, -0.37 D; 95% CI, -0.49 to -0.26 D; P < .001), with 33 of 189 children (17%) in the overminus group vs 2 of 169 (1%) in the nonoverminus group having a shift higher than 1.00 D. Conclusions and Relevance Children 3 to 10 years of age had improved distance exotropia control when assessed wearing overminus spectacles after 12 months of overminus treatment; however, this treatment was associated with increased myopic shift. The beneficial effect of overminus lens therapy on distance exotropia control was not maintained after treatment was tapered off for 3 months and children were examined 3 months later.