Effect of dichoptic video game treatment on mild amblyopia – a pilot study

Purpose: The effect of contrast-balanced dichoptic video game training on distance visual acuity (DVA) and stereo acuity has been investigated in severe-to-moderate amblyopia, but its effect on mild amblyopia and fixation stability has not been assessed. This pilot study aimed to evaluate the effect of home-based dichoptic video game on amblyopic eye DVA, stereo acuity and fixation stability in adults with mild amblyopia. Methods: A randomized single-masked design was adopted. The active 6-week home-based treatment was an anaglyphic, contrast-balanced dichoptic video game, and the placebo was an identical non-dichoptic game. Participants (n = 23) had mild amblyopia (amblyopic DVA ≤ 0.28 log Minimum Angle of Resolution (logMAR)). The primary outcome was change in amblyopic DVA at 6 weeks postrandomization. Near visual acuity, stereo acuity and fixation stability (bivariate contour eclipse area) were also measured. Follow-up occurred at 12 and 24 weeks postrandomization. Results: Mean amblyopic eye DVA was 0.21 ± 0.06 and 0.18 ± 0.06 logMAR for the active (n = 12) and placebo (n = 11) group, respectively. Amblyopic DVA improved significantly more in the active group (0.09 ± 0.05) than in the placebo group (0.03 ± 0.04 logMAR; p < 0.05). The difference between groups remained at 12 weeks postrandomization (p = 0.04) but not at 24 weeks (p = 0.43). Titmus stereo acuities improved significantly more in the active group (0.40 log arcsec) than in the placebo group (0.09 log arcsec) after 6 weeks of gameplay. The between-group difference was still present at 24 weeks postrandomization (p = 0.05). There were no differences between groups on any other secondary outcomes. Conclusion: Home-based dichoptic video gameplay may be an effective method to improve amblyopic DVA and stereo acuity in mild amblyopia.