1. In a small randomized controlled trial, children with myopia treated twice daily with repeated low-level red light therapy had significantly less progression in refractive error at 6 months than children treated with a sham device at 10% power.
2. Spherical equivalent refractive error regressed, indicating myopic control, in 16.1% of children receiving full-power light therapy and 9% receiving sham therapy.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Repeated low-level red light therapy has shown promise in controlling the progression of myopia, or nearsightedness. This trial aimed to use a sham device with 10% powered repeated red-light to enable a double-blind design. Refractive error and axial length of the eye were followed for 112 children randomized to therapy with the full-power or sham devices. All participants were treated twice daily for three minutes with full-power or sham light therapy at home with parental supervision for 6 months. The change in spherical equivalent refractive error at 6 months was 0.06 ± 0.30 diopters in the light therapy group and -0.11 ± 0.33 diopters in the sham group. Regression, or improvement, in refractive error occurred in 16.1% and 9% of children in the intervention and sham groups, respectively. Mean change in the axial length of the eye was also significantly lower in the intervention group, again indicating slower myopic progression. No adverse events related to light therapy were reported. This double-blind study strengthens the evidence in favor of repeated low-level red light therapy for control of myopia. Though the difference between groups was significant at 6 months, the effect size in terms of both refractive error and axial length was modest. Future studies ought to assess red light therapy in combination with pharmacologic and other myopia control therapies.
Relevant Reading: Myopia control 2020: Where are we and where are we heading?
In-Depth [randomized controlled trial]: Children 7-12 years old treated at two hospitals in China for myopia of at least -0.5 diopters and no more than 1.5 diopters of astigmatism were included. Children who had previously used other myopic control therapies such as orthokeratology or atropine were excluded; all participants wore single-vision glasses throughout the study. Randomization followed a randomized allocation algorithm in a 1:1 ratio. Refractive error was measured using autorefraction after pharmacologic dilation. Based on logs kept by parents or guardians to monitor compliance, about 90% of participants received at least 12 treatments per week. The p-value for change in spherical equivalent refraction at 6 months between the two groups was 0.003. In a multivariate generalized estimating equation model adjusting for correlation between eyes, the coefficient for the effect of full-power therapy on change in refractive error was 0.167 diopters, with a 95% confidence interval of 0.050-0.283 diopters. At 6 months, 13 children in the therapy group had a decrease in axial length more than 0.05 mm compared to 3 in the sham group.
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