The effectiveness of binocular amblyopia treatment remains a point of debate, but a new study in Optometry and Vision Science suggests it may be successful in orthotropic children with moderate amblyopia but less so in pediatric patients with microtropia or in severe cases.

Researchers from Texas previously reported binocular amblyopia treatment was more effective than patching as the result of a randomized clinical trial of 28 patients. The current study enrolled an additional 20 children for a total of 48 subjects who were between the ages of four and 10. The investigators randomized 24 children in one group that played a contrast-rebalanced binocular treatment game one hour a day, five days a week, and the other 24 in a second group received patching treatment two hours a day, seven days a week. The primary outcome was change in amblyopic eye best-corrected visual acuity at the two-week visit.

The researchers considered age at enrollment, visual acuity, stereoacuity and suppression, etiology, age at diagnosis, prior treatment and ocular alignment.       

At two weeks, children who played the contrast-rebalanced game had improved visual acuity of 1.5 lines with 10 hours of game play. With a baseline visual acuity of 0.3 to 0.8 logMAR, 35% of children in the binocular game group achieved visual acuity of 0.2 logMAR or better at two weeks compared with only 8% in the patching group.

Baseline visual acuity, ocular alignment and adherence to the treatment protocol were associated with binocular amblyopia treatment success, the researchers noted.

Additionally, children with moderate amblyopia and orthotropia had more visual acuity improvement with binocular game play than those with severe amblyopia.

The study also reported children who spent more time playing the binocular game had greater improvement.

Participants in the study were younger than those enrolled in other investigations, the researchers noted. “Our focus was on enrolling young children, not children who had abandoned treatment and were judged to have intractable residual amblyopia,” they wrote in their paper.

 This investigation included only four children who had prior patching but had stopped due to lack of visual acuity improvement before enrolling in the present study. The remaining children had either no prior patching or took a break from patching to participate.

The investigators noted they were not able to confidently identify any baseline or clinical factors that were associated with response to patching treatment.

Birch EE, Jost RM, Kelly KR, et al. Baseline and clinical factors associated with response to amblyopia treatment in a randomized clinical trial. Optom Vis Sci. 2020;97(5):316-23.