Binocular treatment incorporating a therapeutic Tetris-like video game proved to be no more effective than treatment with a placebo video game among older children, teenagers, and adults with difficult-to-treat amblyopia, Canadian researchers reported.
The home-based binocular modified falling-blocks video game used in the trial appeared to have no significant impact on visual function in study participants with the visual disorder, widely known as “lazy eye.” Mean amblyopic eye visual acuity improved 0.06 (SD 0.12) logMAR from baseline in the active group (n=56) and 0.07 (SD 0.10) logMAR in the placebo group (n=59), according to Benjamin Thompson, PhD, of the University of Waterloo in Waterloo, Ontario, and colleagues.
Adherence to the active falling-block video game treatment was poor in this study, and the 2016 Pediatric Eye Disease Investigator Group (PEDIG) trial, but improved outcomes may be possible with more interesting video games, they suggested in JAMA Ophthalmology.
The current Binocular Treatment of Amblyopia Using Video Games (BRAVO) trial and PEDIG trial showed no significant benefit for the binocular approach to treating amblyopia, Thompson’s group noted.
“Future development of more engaging video games, more sophisticated means of monitoring compliance and attention, and proven effectiveness in randomized clinical trials are required before binocular treatments are ready for use,” they wrote.
Both the active and placebo treatments in the BRAVO trial were falling-blocks video games on Apple iPod Touch devices viewed through red-green anaglyphic glasses worn over refractive correction.
The active video game showed different game elements to each eye, with the amblyopic eye shown a subset of game elements at 100% contrast, while the non-amblyopic eye was shown remaining game elements at a lower contrast set individually using a dichoptic global motion measure of interocular suppression.
“Where participants could not reliably perform this test, fellow eye contrast was manually set to allow simultaneous perception of all game elements during binocular viewing,” the researchers wrote. “Binocular combination was required to successfully play the active video game. Fellow eye contrast increased proportionally by 15% each day if the game was played for at least 15 minutes and a high score of at least 1,000 points was achieved the previous day.”
The placebo game presented all game elements to both eyes at full contrast, simulating a normal video game experience.
The multicenter, double-masked, randomized clinical trial involved 115 participants who were ages ≥7 years with unilateral amblyopia.
The trial design specified that the falling-blocks video game was to be played at home for 1 hour a day for 6 weeks. Change in amblyopic eye visual acuity at 6 weeks was the main measured outcome, while secondary outcomes included compliance, stereoacuity, and interocular suppression.
Of the 115 included participants, 65 (56.5%) were male and 83 (72.2%) were white, and mean age at randomization was 21.5 years.
The authors also reported that 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=0.25).
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 and adverse effects included three reports of transient eye strain.
The researchers noted that compliance fell in weeks 4 to 6, compared with weeks 1 to 3 of treatment, with some participants stating declining interest in the falling-blocks video game during follow-up.
“More engaging content, along with greater game play variety, will help to maintain compliance and attentional engagement over longer treatment periods,” the researchers wrote, adding that the recently developed prescription game DigRush (Amblyotech) may offer a more exciting experience, leading to better compliance.
A randomized trial conducted by the PEDIG investigators comparing DigRush plus spectacle correction with spectacle correction alone in young children began recruitment in early 2017.
In an accompanying commentary, Jonathan Holmes, BM, BCh, of the Mayo Clinic in Rochester, Minnesota, noted that adherence to treatment with the DigRush does appear to be better than with the game used in the BRAVO trial.
“The forthcoming PEDIG randomized clinical trial will provide additional data to answer the question. Is there a dose-response relationship between duration of binocular treatment and improvement in amblyopic eye visual acuity?,” Holmes wrote, adding that, “A positive answer to this question would support the use of binocular treatment for amblyopia.”
The study was funded by the Health Research Council of New Zealand, the Hong Kong Health and Medical Research Fund, and the Victoria government.
Thompson and one co-author disclosed being inventors on two patents that cover the binocular video game treatment used in the trial. One co-author disclosed a relevant relationship with Amblyotech.
Holmes disclosed a relevant relationship with PEDIG.