A Randomized Trial of Binocular Dig Rush Game Treatment for Amblyopia in Children Aged 7 to 12 Years

Abstract

Purpose: To compare visual acuity (VA) improvement in children aged 7 to 12 years with amblyopia treated with a binocular iPad game plus continued spectacle correction vs. continued spectacle correction alone.

Design: Multicenter randomized clinical trial.

Participants: One hundred thirty-eight participants aged 7 to 12 years with amblyopia (33-72 letters, i.e., approximately 20/200 to 20/40) resulting from strabismus, anisometropia, or both. Participants were required to have at least 16 weeks of optical treatment in spectacles if needed or demonstrate no improvement in amblyopic-eye visual acuity (VA) for at least 8 weeks prior to enrollment.

Methods: Eligible participants (mean age 9.6 years, mean baseline VA of 59.6 letters, history of prior amblyopia treatment other than spectacles in 96%) were randomly assigned to treatment for 8 weeks with the dichoptic binocular Dig Rush iPad game (prescribed for 1 hour per day 5 days per week) plus spectacle wear if needed (n = 69) or continued spectacle correction alone if needed (n = 69).

Main outcome measures: Change in amblyopic-eye VA from baseline to 4 weeks, assessed by a masked examiner.

Results: At 4 weeks, mean amblyopic-eye VA letter score improved from baseline by 1.3 (2-sided 95% confidence interval [CI]: 0.1-2.6; 0.026 logMAR) with binocular treatment and by 1.7 (2-sided 95% CI: 0.4-3.0; 0.034 logMAR) with continued spectacle correction alone. After adjusment for baseline VA, the letter score difference between groups (binocular minus control) was -0.3 (95% CI: -2.2 to 1.5, P = 0.71, difference of -0.006 logMAR). No difference in letter scores was observed between groups when the analysis was repeated after 8 weeks of treatment (adjusted mean: -0.1, 98.3% CI: -2.4 to 2.1). For the binocular group, adherence data from the iPad indicated that slightly more than half of the participants (58% and 56%) completed >75% of prescribed treatment by the 4- and 8-week visits, respectively.

Conclusions: In children aged 7 to 12 years who have received previous treatment for amblyopia other than spectacles, there was no benefit to VA or stereoacuity from 4 or 8 weeks of treatment with the dichoptic binocular Dig Rush iPad game.

Trial registration: ClinicalTrials.gov NCT02983552.

Figure 1.

Visit completion by treatment ^a4-week primary outcome visits were classified as being within the analysis window if completed between 21 to <49 days from randomization. Numbers in the parentheses indicate visits completed outside of the analysis window. ^b8-week visits were classified as being within the analysis window if completed between 49 to <105 days from randomization. Numbers in the parentheses indicate visits completed outside of the analysis window. ^c16-week visits were classified as being within the analysis window if completed between 105 to <161 days from randomization. Numbers in the parentheses indicate visits completed outside of the analysis window.

Figure 4a.

Relationship between 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. The scatterplots on the top represent the relationship between change in amblyopic-eye visual acuity from baseline (letters, positive values indicate improvement, r = 0.01) with objective measures of (1) total hours of binocular treatment (left column) and (2) percent change in contrast presented to the fellow eye from baseline (maximum = 80%) to 4 weeks (right column, r = −0.04). The scatterplots on the bottom represent the relationship between change in stereoacuity from baseline (log seconds of arc, positive values indicate improvement) with objective measures of (1) total hours of binocular treatment 437 (left column, r = 0.02) and (2) percent change in contrast presented to the fellow eye from baseline to 4 weeks (right column, r = −0.14).

Figure 4b.

Relationship between 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. The scatterplots on the top represent the relationship between change in amblyopic-eye visual acuity from baseline (letters, positive values indicate improvement, r = - 0.17) from baseline with objective measures of (1) total hours of binocular treatment (left column) and (2) percent change in contrast presented to the fellow eye from baseline (maximum = 80%) to 4 weeks (right column, r = −0.15). The scatterplots on the bottom represent the relationship between change in stereoacuity from baseline (log seconds of arc, positive values indicate improvement) with objective measures of (1) total hours of binocular treatment (left column, r = −0.06) and (2) percent change in contrast presented to the fellow eye from baseline to 4 weeks (right column, r = −0.09).

Figure 4c.

Relationship between hours played and contrast settings (from the log file) with treatment response for visual acuity and stereoacuity after 8 weeks of binocular therapy (all participants with 8 weeks of binocular treatment). Descriptive plots and Pearson correlation coefficients were produced using data pooled across participants in both treatment groups after 8 weeks of prescribed binocular treatment. The scatterplots on the top represent the relationship between change in amblyopic-eye visual acuity from baseline (letters, positive values indicate improvement, r = −0.08) from baseline with objective measures of (1) total hours of binocular treatment (left column) and (2) percent change in contrast presented to the fellow eye from baseline (maximum = 80%) to 4 weeks (right column, r = −0.001). The scatterplots on the bottom represent the relationship between change in stereoacuity from baseline (log seconds of arc, positive values indicate improvement) with objective measures of (1) total hours of binocular treatment (left column, r = −0.05) and (2) percent change in contrast presented to the fellow eye from baseline to 4 weeks (right column, r = −0.001). Descriptive plots and analyses excluded data from participants who completed the final exam (8-week and 16-week exam for the binocular treatment and control treatment groups, respectively) outside of the pre-defined analysis window.