Significance: This study will help to demonstrate the potential value of office-based vergence/accommodative therapy for the treatment of intermittent exotropia and provide data that can be used for planning future clinical trials.
Purpose: This study was designed to evaluate changes in the office control score after office-based vergence/accommodative therapy for intermittent exotropia.
Methods: This was a prospective, unmasked pilot study. Fourteen Chinese participants aged 6 to 18 years with intermittent exotropia (excluding the convergence insufficiency type) were enrolled. All participants received 60 minutes of office-based vergence/accommodative therapy with home reinforcement once per week for 12 weeks. Therapy included vergence, accommodation, saccades and pursuits, antisuppression, and monocular fixation in binocular field techniques. The primary outcome measure was the change in the office control score from the baseline visit to the 13-week outcome visit.
Results: All participants completed the study. The office control score at distance changed by -1.0 (95% confidence interval [CI] = -1.6 to -0.4; P = .005; Cohen's d effect size, 0.93). The distant Look And Cover, then Ten seconds Observation Scale for Exotropia score and distant Newcastle control score total score changed by -0.7 (95% CI, -1.2 to -0.2; P = .02; Cohen's d effect size, 0.55) and -1.9 (95% CI, -2.8 to -1.0; P < .001; Cohen's d effect size, 1.37), respectively. Although there was no significant change in the angle of distance exodeviation (-1.8 prism diopter [Δ] less exodeviation; 95% CI, -3.74 to 0.14Δ; P = .11), a significant change was observed in the near angle (-4.4Δ less exodeviation; 95% CI, -7.3 to -1.5Δ; P = .01; Cohen's d effect size, 0.79). There was no significant change in stereopsis or the Chinese Intermittent Exotropia Questionnaire score.
Conclusions: In this select group of children with intermittent exotropia, 12 weeks of office-based vergence/accommodative therapy with home reinforcement resulted in a statistically and clinically significant improvement in the distance control of exodeviation and the near exodeviation magnitude. These results suggest that there is a need for a randomized clinical trial designed to determine the effectiveness of vision therapy as a treatment modality for intermittent exotropia.
Trial registration: ClinicalTrials.gov NCT03321838.