Baseline and Clinical Factors Associated with Response to Amblyopia Treatment in a Randomized Clinical Trial

Abstract

Significance: We sought to identify baseline and clinical factors that were predictive of the response to amblyopia treatment. We report that binocular amblyopia treatment may be especially effective for moderate amblyopia in orthotropic children.

Purpose: We previously reported results from the primary cohort (n = 28) enrolled in a randomized clinical trial (NCT02365090), which found that binocular amblyopia treatment was more effective than patching. Enrollment of an additional 20 children was pre-planned to provide the opportunity to examine factors that may be predictive of response to amblyopia treatment.

Methods: Forty-eight children (4 to 10 years old) were enrolled, with 24 randomized to contrast-rebalanced binocular game treatment (1 hour a day, 5 days a week) and 24 to patching treatment (2 hours a day, 7 days a week). The primary outcome was change in amblyopic eye best-corrected visual acuity at the 2-week visit. Baseline factors examined were age at enrollment, visual acuity, stereoacuity, and suppression. Clinical factors were etiology, age at diagnosis, prior treatment, and ocular alignment.

Results: At 2 weeks, visual acuity improvement was significantly greater with the binocular game than patching. Children with moderate amblyopia and orthotropia had more visual acuity improvement with binocular game play than did those with severe amblyopia. In addition, children who spent more time playing the binocular game had more improvement. We were not able to confidently identify any baseline or clinical factors that were associated with response to patching treatment.

Conclusions: Binocular amblyopia treatment was more effective among orthotropic children with moderate amblyopia than among children with microtropia or severe amblyopia.

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Birch et al. Optometry and Vision Science, May 2020

Figure 1.

Best-corrected visual acuity (BCVA) for the amblyopic eye at baseline and after 2 weeks of playing a contrast re-balanced binocular iPad game (1 hr/day 5 days/wk) or patching the fellow eye (2 hr/day 7 days/wk). A larger improvement occurred for children randomized to play the binocular game compared with children who were randomized to patching.

Figure 2.

Amount of best-corrected visual acuity (BCVA) improvement for the amblyopic eye for subgroups of children who were playing the contrast re-balanced binocular iPad game. Baseline (left) and clinical variables (right) were dichotomized, based on criteria commonly used in clinical treatment trials for amblyopia.^- Binocular amblyopia treatment was more effective among orthotropic children with moderate amblyopia than among children with microtropia or severe amblyopia.

Figure 3.

Amount of best-corrected visual acuity (BCVA) improvement for the amblyopic eye for subgroups of children who were patching. Baseline (left) and clinical variables (right) were dichotomized, based on criteria commonly used in clinical treatment trials for amblyopia.^- We were not able to confidently identify any baseline or clinical factors that were associated with response to patching treatment.

Figure 4.

Amount of best-corrected visual acuity (BCVA) improvement for the amblyopic eye as a function of the number of hours of treatment for children randomized to play the binocular game (top) and children who were randomized to patching (bottom). There was a moderate linear relationship between hours of binocular game play and the amount of BCVA improvement observed. In the patching group, we were unable to confidently identify a relationship between hours of patching and the amount of AE BCVA improvement observed.