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

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 PARTICIPANTSThe 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 MEASURESChange 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. RESULTSOf 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 RELEVANCEThe 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.

From suppression to stereoacuity: a composite binocular function score for clinical research

“…The composite BF score has been successfully used in recent amblyopia treatment trials for analysis of treatment effects . The scale is ordinal, rather than continuous, therefore, outcomes are analysed with non‐parametric statistics.…”

“…The composite BF score has been successfully used in recent amblyopia treatment trials for analysis of treatment effects. 8,9 The scale is ordinal, rather than continuous, therefore, outcomes are analysed with non-parametric statistics. We have shown that the composite score highly correlates with both a measure of inter-ocular suppression and with a threshold measure of stereoacuity that tests coarse levels of binocular disparity detection beyond the range of common clinical tests.…”

“…In addition to reporting visual acuity change, recent amblyopia treatment studies, including randomised clinical trials, have sought to quantify changes in the level of suppression or stereoacuity . This requires recording binocular function in individuals with a broad range of measureable stereoacuity through to those with complete suppression and no measurable stereopsis.…”

Optical treatment of amblyopia in older children and adults is essential prior to enrolment in a clinical trial

“…The BRAVO study was a placebo-controlled, doublemasked randomised clinical trial of an iPod-based binocular videogame treatment for amblyopia in older children and adults (see Guo, Babu & Black et al 33 for the full study protocol and Gao, Guo, Babu et al 34 for the trial results). The trial included participants with unilateral amblyopia due to anisometropia and/or strabismus who were not currently undergoing any amblyopia therapy apart from wearing refractive correction.…”

The effect of combined patching and citalopram on visual acuity in adults with amblyopia: a randomized, crossover, placebo-controlled trial

“…A growing body of literature demonstrates that vision can improve in adult humans with amblyopia through interventions such as monocular [21,22] and binocular [23][24][25][26][27] perceptual learning and non-invasive brain stimulation [28][29][30][31][32]. However, these approaches have not yet translated into positive randomized clinical trials in adult patients that are required for translation into clinical practice [33].…”