A Randomized Trial of a Binocular iPad Game Versus Part-Time Patching in Children Aged 13 to 16 Years With Amblyopia

Abstract

Purpose: To compare visual acuity (VA) improvement in teenagers with amblyopia treated with a binocular iPad game vs part-time patching.

Methods: One hundred participants aged 13 to <17 years (mean 14.3 years) with amblyopia (20/40 to 20/200, mean ∼20/63) resulting from strabismus, anisometropia, or both were enrolled into a randomized clinical trial. Participants were randomly assigned to treatment for 16 weeks of either a binocular iPad game prescribed for 1 hour per day (n = 40) or patching of the fellow eye prescribed for 2 hours per day (n = 60). The main outcome measure was change in amblyopic eye VA from baseline to 16 weeks.

Results: Mean amblyopic eye VA improved from baseline by 3.5 letters (2-sided 95% confidence interval [CI]: 1.3-5.7 letters) in the binocular group and by 6.5 letters (2-sided 95% CI: 4.4-8.5 letters) in the patching group. After adjusting for baseline VA, the difference between the binocular and patching groups was -2.7 letters (95% CI: -5.7 to 0.3 letters, P = .082) or 0.5 lines, favoring patching. In the binocular group, treatment adherence data from the iPad device indicated that only 13% of participants completed >75% of prescribed treatment.

Conclusions: In teenagers aged 13 to <17 years, improvement in amblyopic eye VA with the binocular iPad game used in this study was not found to be better than patching, and was possibly worse. Nevertheless, it remains unclear whether the minimal treatment response to binocular treatment was owing to poor treatment adherence or lack of treatment effect.

Figure 1.

(top) Nonius cross: This red/green Nonius cross is aligned by the participant at the start of each session to allow game elements to be adjusted to compensate for small ocular misalignments. (bottom)Falling blocks game: The falling blocks game on the “hard” level of difficulty.

Figure 1.

(top) Nonius cross: This red/green Nonius cross is aligned by the participant at the start of each session to allow game elements to be adjusted to compensate for small ocular misalignments. (bottom)Falling blocks game: The falling blocks game on the “hard” level of difficulty.

Figure 2.

Visit completion by treatment group: Flowchart showing study completion in each treatment group.

Figure 3.

Change in Amblyopic-eye Visual Acuity (VA) from Baseline across Follow-up Visits: At each time point, the box on the left is the distribution of change (letters) in amblyopic eye VA from baseline for the binocular group and that on the right represents the patching group. Positive values for VA change indicate improvement. The bottom and top of each box represents the 25th and 75th percentiles of the data and the line in the box is the median. The treatment group means are represented by a dot and are connected across the visits with either a solid line (binocular group) or a dashed line (patching group). The bars extending above and below each box extend to the closest observed data point inside 1.5 times the interquartile range (difference between the 25th and 75th percentiles). The open circles represent near statistical outliers and the asterisks indicate far outliers.

Figure 4.

Relationship between Change in 4-Week Outcomes and Objective Adherence Measures in the Binocular Group: Relationship between change in 4-week outcomes and objective adherence measures (total hours of game play, change in fellow-eye contrast from baseline) in the binocular group were evaluated in a post hoc analysis using descriptive statistics and scatterplots. The scatterplots on the top row represent the relationship between the change in 4-week amblyopic-eye visual acuity (VA) from baseline and (1) cumulative hours of binocular treatment at 4 weeks (top left) and (2) change in fellow-eye contrast from baseline to 4 weeks (top right). The scatterplots on the bottom row represent the relationship between the change in 4-week stereoacuity from baseline and (1) cumulative hours of binocular treatment at 4 weeks (bottom left) and (2) change in fellow-eye contrast from baseline to 4 weeks (bottom right). Positive values for change in VA and stereoacuity indicate improvement. Analyses were limited to participants who completed the 4-week visit within the pre-defined analysis window (3 to <6 weeks after randomization).

Figure 5.

Relationship between Change in 16-Week Outcomes and Objective Adherence Measures in the Binocular Group: Relationship between change in 16-week outcomes and objective adherence measures (total hours of game play, change in fellow-eye contrast from baseline) in the binocular group were evaluated using descriptive statistics and scatterplots. The scatterplots on the top row represent the relationship between the change in 16-week amblyopic-eye visual acuity (VA) from baseline and (1) cumulative hours of binocular treatment at 16 weeks (top left) and (2) change in fellow-eye contrast from baseline to 16 weeks (top right). The scatterplots on the bottom row represent the relationship between the change in 16-week stereoacuity from baseline and (1) cumulative hours of binocular treatment at 16 weeks (bottom left) and (2) change in fellow-eye contrast from baseline to 16 weeks (bottom right). Positive values for change in VA and stereoacuity indicate improvement. Analyses were limited to participants who completed the 16-week visit within the pre-defined analysis window (14 to <20 weeks after randomization).