A Randomized Clinical Trial Comparing Eyetronix Flicker Glass and Patching for Treatment of Amblyopia in Children Reveals Similar Improvements in Vision

Abstract

PurposeRecently, Eyetronix Flicker Glass (EFG) has been introduced as a novel treatment for amblyopia. It alternatively deprives the visual input of each eye rapidly (e.g., 7 Hz). However, whether it is comparable with standard patching therapy is unclear. In this randomized clinical trial, we evaluate the efficacy of an EFG therapy as treatment for amblyopia in children and compare it to the patching therapy.MethodsWe tested 31 children (aged 4–13 years) with amblyopia. They were assigned into one of the two treatment groups and were treated for 12 weeks. The first group was treated with EFG for 1 h/day (Flicker Group) and the latter with a standard patch (Patching Group) for 2 h/day. We designated changes from baseline in best-corrected visual acuity (BCVA) of the amblyopic eye as our primary outcome. Changes from baseline in other visual outcomes, such as contrast sensitivity, stereopsis, and fusional vergence range were measured as secondary outcome.ResultsBCVA improved significantly at 12 weeks relative to baseline in both the Flicker (0.13 ± 0.11 logMAR; mean ± SD) and Patching Groups (0.21 ± 0.14 logMAR). However, the improvements were not significantly different between groups (p = 0.13). Contrast sensitivity also significantly improved at 3 and 12 cycles/degree between baseline and 12 weeks in both groups (p’s < 0.05). However, stereopsis and fusion range did not improve significantly in both groups.ConclusionAn EFG therapy and patching improved BCVA similarly for children with amblyopia at 12 weeks. Both therapies improved the contrast sensitivity at 3 and 12 cycles per degree (cpd); however, only patching improved the contrast sensitivity at 6 cpd. Both therapies did not benefit binocular visual functions (stereopsis and fusional vergence range). We believe that EFG can be an additional choice for therapy.Clinical Trial Registrationchictr.org number: ChiCTR2000034436.

Rapid Alternate Flicker Modulates Binocular Interaction in Adults With Abnormal Binocular Vision

“…43 The improvement in stereopsis is debatable. 24 , 25 , 44 , 45 The findings from this study should not be compared to these findings directly. First, the binocular balance was quantified while EFG was on in this study.…”

“…Additional amblyopic studies have also revealed that visual acuity and stereopsis can be improved at 7 Hz. 24 , 25 Therefore, we hypothesized that dichoptic alternative flicker stimuli could modify binocular interaction by the time difference between interocular excitatory and inhibitory responses, which in turn affects sensory eye balance in binocular processing.…”

Issues Revisited: Shifts in Binocular Balance Depend on the Deprivation Duration in Normal and Amblyopic Adults

“…Both show that these visual improvements can be sustained for up to 1 year after the treatment [ 32 , 33 ]. A future study should directly investigate the effects of longitudinal inverse deprivation on various visual functions, such as interocular suppression and monocular contrast sensitivity of the deprived eye, stereopsis, and whether changes or improvements in these visual functions following inverse patching persist [ 13 , 52 – 54 ].…”

The impact of autostereoscopic screens on assessing depth perception

“…Jost et al (10), recently showed amblyopic visual acuity gains and stereopsis gains with dichoptic movie therapy on a Nintendo 3DS screen comparable to patching. Flicker glasses-somewhat similar to Wang's study, can provide amblyopia therapy with success similar to patching (11).…”