Myopia Control Effect of Repeated Low-Level Red-Light Therapy in Chinese Children: A Randomized, Double-Blind, Controlled Clinical Trial

Abstract

Purpose: Repeated low-level red-light (RLRL) therapy is an emerging treatment for myopia control. Nevertheless, previous studies are limited by open-label design. Our study aimed to assess the efficacy and safety of RLRL therapy in controlling myopia progression compared to a sham device with only 10% of the original power.

Design: Randomized, double-blind, controlled clinical trial.

Participants: A total of 112 Chinese children aged 7 to 12 years with myopia of at least -0.50 diopter (D), astigmatism of 1.50 D or less, and anisometropia of 1.50 D or less.

Methods: Participants were assigned randomly in a 1:1 ratio to the RLRL group or the sham device control group, following a schedule of 3 minutes per session, twice daily, with an interval between sessions of at least 4 hours. The RLRL therapy was provided by a desktop red-light therapy device and administered at home. The sham device was the same device but with only 10% of the original device's power. Cycloplegic refraction and axial length (AL) were measured at baseline and 6 months.

Main outcome measures: Changes in cycloplegic spherical equivalence refraction (SER) and AL between 2 groups were compared using a generalized estimating equation (GEE).

Results: A total of 111 children were included in the analysis (n = 56 in the RLRL group and n = 55 in the sham device control group). The mean SER change over 6 months was 0.06 ± 0.30 D in the RLRL group and -0.11 ± 0.33 D in the sham device control group (P = 0.003), with respective mean increases in AL of 0.02 ± 0.11 mm and 0.13 ± 0.10 mm (P < 0.001). In the multivariate GEE models, children in the RLRL group showed less myopia progression and axial elongation than those in the sham device control group (SER: coefficient, 0.167 D; 95% confidence interval [CI], 0.050-0.283 D; P = 0.005; AL: coefficient, -0.101 mm; 95% CI, -0.139 to -0.062 mm; P < 0.001). No treatment-related adverse events were reported.

Conclusions: In myopic children, RLRL therapy with 100% power significantly reduced myopia progression over 6 months compared with those treated with a sham device of 10% original power. The RLRL treatment was well tolerated without treatment-related adverse effects.

Keywords: Myopia; Randomized clinical trial; Repeated low-level red-light (RLRL) therapy.