Melia, B. Michele

SIGNIFICANCE This pilot randomized trial, the first to evaluate a specific base‐in relieving prism treatment strategy for childhood intermittent exotropia, did not support proceeding to a full‐scale clinical trial. Defining and measuring prism adaptation in children with intermittent exotropia are challenging and need further study. PURPOSE This study aimed to determine whether to proceed to a full‐scale trial of relieving base‐in prism spectacles versus refractive correction alone for children with intermittent exotropia. METHODS Children 3 years old to those younger than 13 years with distance intermittent exotropia control score of ≥2 points on the Intermittent Exotropia Office Control Scale (Strabismus 2006;14:147–150; 0 [phoria] to 5 [constant]), ≥1 episode of spontaneous exotropia, and 16 to 35∆ by prism‐and‐alternate‐cover test, who did not fully prism adapt on a 30‐minute in‐office prism‐adaptation test were randomized to base‐in relieving prism (40% of the larger of distance and near exodeviations) or nonprism spectacles for 8 weeks. A priori criteria to conduct a full‐scale trial were defined for the adjusted treatment group difference in mean distance control: “proceed” (≥0.75 points favoring prism), “uncertain” (>0 to <0.75 points favoring prism), or “do not proceed” (≥0 points favoring nonprism). RESULTS Fifty‐seven children (mean age, 6.6 ± 2.2 years; mean baseline distance control, 3.5 points) received prism (n = 28) or nonprism (n = 29) spectacles. At 8 weeks, mean control values were 3.6 and 3.3 points in prism (n = 25) and nonprism (n = 25) groups, respectively, with an adjusted difference of 0.3 points (95% confidence interval, −0.5 to 1.1 points) favoring nonprism (meeting our a priori “do not proceed” criterion). CONCLUSIONS Base‐in prism spectacles, equal to 40% of the larger of the exodeviations at distance or near, worn for 8 weeks by 3‐ to 12‐year‐old children with intermittent exotropia did not yield better distance control than refractive correction alone, with the confidence interval indicating that a favorable effect of 0.75 points or larger is unlikely. There was insufficient evidence to warrant a full‐scale randomized trial.

Abstract Purpose To describe the clinical course of untreated intermittent exotropia (IXT) in children 12–35 months of age followed for 3 years. Methods We enrolled 97 children 12–35 months of age with previously untreated IXT who had been randomly assigned to the observation arm of a randomised trial of short‐term occlusion versus observation. Participants were observed unless deterioration criteria were met at a follow‐up visit occurring at 3 months, 6 months, and 6‐month intervals thereafter for 3 years. The primary outcome was deterioration of the IXT by 3 years, defined as (1) a constant exotropia ≥10 prism dioptres (∆) at distance and near (i.e., motor deterioration) or (2) treatment prescribed despite not having met motor deterioration. The primary analysis used the Kaplan‐Meier method to determine the cumulative proportion of participants meeting deterioration by three years and 95% confidence interval (CI). Results The cumulative probability of deterioration by 3 years was 28% (95% CI = 20%–39%). Of the 24 participants meeting the primary outcome of deterioration, seven met motor deterioration and 17 were prescribed treatment without meeting motor deterioration. The cumulative probability of motor deterioration by 3 years was 10% (95% CI = 5%–19%). Conclusions Given the modest rate of motor deterioration over three years, watchful waiting may be a reasonable management approach in 12‐ to 35‐month‐old children with IXT. To confirm this recommendation would require a long‐term randomised trial of immediate treatment versus observation followed by deferred treatment if needed.

ABSTRACT Purpose We conducted a pilot randomized clinical trial of office‐based active vision therapy for the treatment of childhood amblyopia to determine the feasibility of conducting a full‐scale randomized clinical trial. Methods A training and certification program and manual of procedures were developed to certify therapists to administer a standardized vision therapy program in ophthalmology and optometry offices consisting of weekly visits for 16 weeks. Nineteen children, aged 7 to less than 13 years, with amblyopia (20/40–20/100) were randomly assigned to receive either 2 hours of daily patching with active vision therapy or 2 hours of daily patching with placebo vision therapy. Results Therapists in diverse practice settings were successfully trained and certified to perform standardized vision therapy in strict adherence with protocol. Subjects completed 85% of required weekly in‐office vision therapy visits. Eligibility criteria based on age, visual acuity, and stereoacuity, designed to identify children able to complete a standardized vision therapy program and judged likely to benefit from this treatment, led to a high proportion of screened subjects being judged ineligible, resulting in insufficient recruitment. There were difficulties in retrieving adherence data for the computerized home therapy procedures. Conclusions This study demonstrated that a 16‐week treatment trial of vision therapy was feasible with respect to maintaining protocol adherence; however, recruitment under the proposed eligibility criteria, necessitated by the standardized approach to vision therapy, was not successful. A randomized clinical trial of in‐office vision therapy for the treatment of amblyopia would require broadening of the eligibility criteria and improved methods to gather objective data regarding the home therapy. A more flexible approach that customizes vision therapy based on subject age, visual acuity, and stereopsis might be required to allow enrollment of a broader group of subjects.