Purpose
To compare the efficacy and safety of low-level red light (LRL) in controlling myopia progression at 3 different powers: 0.37 mW, 0.60 mW, and 1.20 mW.
Design
Single-center, single-masked, randomized controlled trial.
Participants
Two hundred children aged 6-15 with myopia of –0.50 diopter (D) or more and astigmatism of –2.50 D or less were enrolled from April to May 2022. Follow-up ended in December 2022.
Methods
Participants were assigned randomly to 3 intervention groups and 1 control group (1:1:1:1). All participants wore single-vision spectacles. Moreover, the intervention group randomly received LRL at 3 different powers twice daily for 3 minutes per session, with a minimum 4-hour interval.
Main Outcome Measures
Changes in spherical equivalent (SE), axial length (AL), and subfoveal choroidal thickness (SFCT) were measured.
Results
After 6 months, SE progression was significantly lower in the 0.37-mW group (0.01 D; 95% confidence interval [CI], –0.12 to 0.15), 0.60-mW group (–0.05 D; 95% CI, –0.18 to 0.07), and 1.20-mW group (0.16 D; 95% CI, 0.03 to 0.30) compared to the control group (–0.22 D; 95% CI, –0.50 to 0.30; adjusted P < 0.001 for all). AL changes in the 0.37-mW group (0.04 mm; 95% CI, –0.01 to 0.08), 0.60-mW group (0.00 mm; 95% CI, –0.05 to 0.05), and 1.20-mW group (–0.04 mm; 95% CI, –0.08 to 0.01) were significantly smaller than the control group (0.27 mm; 95% CI, 0.22 to 0.33; adjusted P < 0.001 for all). Similarly, increases in SFCT were significantly greater in the 0.37-mW group (22.63 μm; 95% CI, 12.13 to 33.34 μm), 0.60-mW group (36.17 μm; 95% CI, 24.37 to 48.25 μm), and 1.20-mW group (42.59 μm; 95% CI, 23.43 to 66.24 μm) than the control group (–5.07 μm; 95% CI, –10.32 to –0.13 μm; adjusted P < 0.001 for all). No adverse events were observed.
Conclusions
LRL effectively controlled myopia progression at 0.37 mW, 0.60 mW, and 1.20 mW. Further research is required.
Financial Disclosure(s)
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
