Effect of Repeated Low-Level Red-Light Therapy in Myopia Control in Children: A Multicenter Randomized Controlled Trial

Abstract Purpose To assess the efficacy and safety of repeated low-level red-light (RLRL) therapy in myopia control in children. Design Multicenter, randomized, parallel-group, single-blind clinical trial. Participants A total of 264 eligible children aged 8 to 13 years with myopia of cycloplegic spherical equivalent refraction (SER) of -1.00 to -5.00D, astigmatism 2.50D, anisometropia 1.50D, best-corrected visual acuity (BCVA) > 0.0 logMAR (Snellen 1.0 or 20/20) were enrolled in July to August 2019. Follow-up was completed in September 2020. Methods Children were randomly assigned to the intervention group [RLRL treatment plus single vision spectacle (SVS)] and control group (SVS). The RLRL treatment was provided by a desktop light therapy device which emits red light of 650 nm in wavelength, at an illuminance level of approximately 1600 lux and a power of 0.29 mW for a 4-mm pupil (Class I Classification), and was administered at home under supervision of parents, 3 minutes per session, twice per day with a minimum interval of 4-hours, five days per week. Main outcome measures The primary outcome and a key secondary outcome were changes in axial length (AL) and SER measured at baseline, and 1-, 3-, 6- and 12-month follow-up visits. Participants who had at least one post-randomization follow-up visit were analyzed for treatment efficacy based on a longitudinal mixed model. Results Among 264 randomized participants, 246 (93.2%) children were included in the analysis (n = 117 in the RLRL and n = 129 in the SVS group). Adjusted 12-month axial elongation and SER progression were 0.13 mm (95% CI: 0.09 to 0.17) and -0.20 D (95% CI: -0.29 to -0.11) for RLRL treatment, 0.38 mm (95% CI: 0.34 to 0.42) and -0.79 D (95%CI, -0.88 to -0.69) for SVS. The difference in axial elongation and SER progression were 0.26 mm (95% CI: 0.20 to 0.31) and -0.59 D (95% CI: -0.72 to -0.46) between the RLRL and SVS groups. No severe adverse events (sudden vision loss by 2 lines or scotoma developed), functional visual loss indicated by BCVA, or structural damage seen on optical coherence tomography scans were observed. Conclusions RLRL therapy is a promising alternative treatment for myopia control in children with good user acceptability and no documented functional and structural damages.