Effectiveness of a Binocular Video Game vs Placebo Video Game for Improving Visual Functions in Older Children, Teenagers, and Adults With Amblyopia: A Randomized Clinical Trial

Abstract

Importance: Binocular amblyopia treatment using contrast-rebalanced stimuli showed promise in laboratory studies and requires clinical trial investigation in a home-based setting.

Objective: To compare the effectiveness of a binocular video game with a placebo video game for improving visual functions in older children and adults.

Design, setting, and participants: The Binocular Treatment of Amblyopia Using Videogames clinical trial was a multicenter, double-masked, randomized clinical trial. Between March 2014 and June 2016, 115 participants 7 years and older with unilateral amblyopia (amblyopic eye visual acuity, 0.30-1.00 logMAR; Snellen equivalent, 20/40-20/200) due to anisometropia, strabismus, or both were recruited. Eligible participants were allocated with equal chance to receive either the active or the placebo video game, with minimization stratified by age group (child, age 7 to 12 years; teenager, age 13 to 17 years; and adult, 18 years and older).

Interventions: Falling-blocks video games played at home on an iPod Touch for 1 hour per day for 6 weeks. The active video game had game elements split between eyes with a dichoptic contrast offset (mean [SD] initial fellow eye contrast, 0.23 [0.14]). The placebo video game presented identical images to both eyes.

Main outcomes and measures: Change in amblyopic eye visual acuity at 6 weeks. Secondary outcomes included compliance, stereoacuity, and interocular suppression. Participants and clinicians who measured outcomes were masked to treatment allocation.

Results: Of the 115 included participants, 65 (56.5%) were male and 83 (72.2%) were white, and the mean (SD) age at randomization was 21.5 (13.6) years. There were 89 participants (77.4%) who had prior occlusion. The mean (SD) amblyopic eye visual acuity improved 0.06 (0.12) logMAR from baseline in the active group (n = 56) and 0.07 (0.10) logMAR in the placebo group (n = 59). The mean treatment difference between groups, adjusted for baseline visual acuity and age group, was -0.02 logMAR (95% CI, -0.06 to 0.02; P = .25). Compliance with more than 25% of prescribed game play was achieved by 36 participants (64%) in the active group and by 49 (83%) in the placebo group. At 6 weeks, 36 participants (64%) in the active group achieved fellow eye contrast greater than 0.9 in the binocular video game. No group differences were observed for any secondary outcomes. Adverse effects included 3 reports of transient asthenopia.

Conclusions and relevance: The specific home-based binocular falling-blocks video game used in this clinical trial did not improve visual outcomes more than the placebo video game despite increases in fellow eye contrast during game play. More engaging video games with considerations for compliance may improve effectiveness.

Trial registration: anzctr.org.au Identifier: ACTRN12613001004752.

Conflict of interest statement

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs Thompson and Hess are named inventors on 2 patents that cover the binocular video game treatment used in the main Binocular Treatment of Amblyopia Using Videogames (BRAVO) clinical trial (patents US 12528934 and US 8006372 B2). Dr Hess is a scientific advisor to Amblyotech, a company that licenses the patents. No other disclosures were reported.

Figures

Figure 1.. CONSORT Flowchart

The total number of protocol violations is less than the sum of all categories because some participants had more than 1 protocol violation. Detailed descriptions of protocol violations can be found in the eAppendix in Supplement 2.

Figure 2.. Scatterplots of Changes in Visual Functions vs Cumulative Game Play Duration at 6 Weeks

A, There were 18 participants aged 7 to 12 years, 8 aged 13 to 17 years, and 24 aged 18 years or older. B, There were 23 participants aged 7 to 12 years, 9 aged 13 to 17 years, and 25 aged 18 years or older. For all y-axes, positive change values indicate improvement from baseline. Each data point represents 1 participant. Participants were prescribed a total minimum dose of 42 hours of video game treatment over 6 weeks.