A Flicker Therapy for the Treatment of Amblyopia

Background: Standard clinical treatment methods for amblyopia penalize the nonamblyopic eye, with subsequent compliance problems, and do not address the associated binocular vision abnormality. The purpose of this study is to evaluate a novel approach to amblyopia treatment that uses rapid alternating occlusion and flicker and aims to improve monocular and binocular vision. Methods: A pre-post (12 weeks) interventional study with historical data control. Children with anisometropic amblyopia (ages 5 to 17 years, n=23) were enrolled by consecutive sample. Subjects wore Eyetronix Flicker Glass, shutter glasses with liquid crystal lenses that rapidly alternated occlusion at a programmable frequency, for 1-2 hours daily while performing a near task of their choice, e.g., homework, computer. Outcome measures were: (1) bestcorrected LogMAR visual acuity (BCVA) and (2) Random Dot 2 stereopsis. Results: After 12 weeks of therapy, 96% (n=22) of the children treated improved BCVA in the amblyopic eye (p<0.001) - over 26% (n=6) improved 2 LogMAR lines or more (fellow eye BCVA did not change) - and 89% of the children with reliable data (n=18) improved global stereopsis. Conclusions: This relatively passive therapy has shown encouraging results as a potential treatment for amblyopia. The improvement in BCVA is comparable to previous studies that used traditional amblyopia therapies. The improvement in stereopsis suggests that the therapy promotes binocular vision. Notably, BCVA and stereopsis improved across all ages and in subjects who had previously plateaued with conventional therapies. Randomized masked and controlled studies are the next step to further quantify the clinical efficacy of this therapy.