A Randomized Trial of Binocular Dig Rush Game Treatment for Amblyopia in Children Aged 4 to 6 Years

Abstract

Significance: Binocular treatment for unilateral amblyopia is an emerging treatment that requires evaluation through a randomized clinical trial.

Purpose: This study aimed to compare change in amblyopic-eye visual acuity (VA) in children aged 4 to 6 years treated with the dichoptic binocular iPad (Apple, Cupertino, CA) game, Dig Rush (not yet commercially available; Ubisoft, Montreal, Canada), plus continued spectacle correction versus continued spectacle correction alone.

Methods: Children (mean age, 5.7 years) were randomly assigned to home treatment for 8 weeks with the iPad game (prescribed 1 h/d, 5 d/wk [n = 92], or continued spectacle correction alone [n = 90]) in a multicenter randomized clinical trial. Before enrollment, children wearing spectacles were required to have at least 16 weeks of wear or no improvement in amblyopic-eye VA (<0.1 logMAR) for at least 8 weeks. Outcome was change in amblyopic-eye VA from baseline to 4 weeks (primary) and 8 weeks (secondary) assessed by masked examiner.

Results: A total of 182 children with anisometropic (63%), strabismic (16%; <5∆ near, simultaneous prism and cover test), or combined-mechanism (20%) amblyopia (20/40 to 20/200; mean, 20/63) were enrolled. After 4 weeks, mean amblyopic VA improved by 1.1 logMAR lines with binocular treatment and 0.6 logMAR lines with spectacles alone (adjusted difference, 0.5 lines; 95.1% confidence interval [CI], 0.1 to 0.9). After 8 weeks, results (binocular treatment: mean amblyopic-eye VA improvement, 1.3 vs. 1.0 logMAR lines with spectacles alone; adjusted difference, 0.3 lines; 98.4% CI, -0.2 to 0.8 lines) were inconclusive because the CI included both zero and the pre-defined difference in mean VA change of 0.75 logMAR lines.

Conclusions: In 4- to 6-year-old children with amblyopia, binocular Dig Rush treatment resulted in greater improvement in amblyopic-eye VA for 4 weeks but not 8 weeks. Future work is required to determine if modifications to the contrast increment algorithm or other aspects of the game or its implementation could enhance the treatment effect.

Trial registration: ClinicalTrials.gov NCT02983552.

Conflict of interest statement

Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest.

Copyright © 2022 American Academy of Optometry.

Figures

Appendix Figure A1,

available at http://links.lww.com/OPX/A561: Relationship between total hours of binocular game play and contrast presented to the fellow eye after 4 and 8 weeks of treatment (binocular treatment group).

Figure 1.

Visit completion by treatment group. The 4-week primary outcome visits were classified as being within the analysis window if completed between 21 to

Figure 2.

(A) Amblyopic-eye visual acuity at randomization (baseline) and outcome visits by treatment group. At each time point, the left box represents the binocular treatment group and the right box represents the continued spectacles group. Bottom and top of each box represent the 25th and 75th percentiles; the line in the box is the median and the dot is the mean. Bars above and below extend to the closest observed data point inside 1.5 times the interquartile range and open circles represent statistical outliers. Analyses were limited to 4-week (21 to <49 days after randomization) and 8-week (49 to <105 days after randomization) exams completed within the pre-defined analysis windows.(B) Change in amblyopic-eye visual acuity from baseline to outcome visits by treatment group. At each time point, the left box represents the binocular treatment group and the right box represents the continued spectacles group. Bottom and top of each box represent the 25th and 75th percentiles; the line in the box is the median and the dot is the mean. Bars above and below extend to the closest observed data point inside 1.5 times the interquartile range and open circles represent statistical outliers. Analyses were limited to 4-week (21 to <49 days after randomization) and 8-week (49 to <105 days after randomization) exams completed within the pre-defined analysis windows.

Figure 3.

Treatment group difference in the mean change in amblyopic-eye visual acuity from baseline to 4 weeks according to baseline subgroups. Positive differences favor the binocular treatment group. Subgroup analyses were limited to participants who completed the 4-week outcome visit within the pre-defined analysis window (21 to P-values were not computed for categorical subgroup factors with fewer than 20 participants per treatment group in one or more subgroup levels. Statistical significance of the interaction term was based on a 2-sided alpha of 0.01.

Figure 4.

Relationships of hours played and contrast settings (from the log file) with treatment response for visual acuity and stereoacuity after 4 weeks of binocular therapy (binocular treatment group). Descriptive plots and Pearson correlation coefficients were produced using 4-week data from participants in the binocular treatment group who completed the visit within the pre-defined analysis window (21 to

Figure 5.

Relationships of hours played and contrast settings (from the log file) with treatment response for visual acuity and stereoacuity after 8 weeks of binocular therapy (binocular treatment group). Descriptive plots and Pearson correlation coefficients were produced using 8-week data from participants in the binocular treatment group who completed the visit within the pre-defined analysis window (49 to