This study aimed to compare the efficacy and safety of low-intensity red light (LRL) in controlling myopia progression across three different powers (0.37 mW, 0.60 mW, and 1.20 mW).
Single-center, single-blind, randomized controlled trial.
A total of 200 children aged 6 to 15 years with myopia ≥ -0.50 diopter (D) and astigmatism ≤ -2.5 D were enrolled from April to May 2022. Follow-up ended in December 2022.
Participants were randomly assigned to three intervention groups and one control group (1:1:1:1 ratio). The intervention group wore single-vision spectacle (SVS) throughout the day and were randomly received LRL therapy at 0.37 mW, 0.60 mW and 1.20 mW twice per day for 3 minutes each session, with at least a 4-hour interval. The control group only wore an SVS throughout the day.
Changes in spherical equivalent (SE), axial length (AL), and subfoveal choroidal thickness (SFCT) were measured.
At the end of 6 months, the progression of SE in the 0.37 mW [0.01D (95%CI: -0.12, 0.15)], 0.60 mW [(-0.05D (95%CI: -0.18, 0.07)], and 1.20 mW [0.16D (95%CI: 0.03, 0.30)] groups were significantly lower than control group [-0.22D (95%CI: -0.50, 0.30)] (All P< 0.001). The changes of AL in the 0.37 mW [0.04mm (95%CI: -0.01, 0.08)], 0.60 mW [0.00mm (95%CI: -0.05, 0.55)], and 1.20 mW [-0.04 mm (95%CI: -0.08, 0.01)] groups were significantly smaller than control group [0.27mm (95%CI: 0.22, 0.33)] (All P< 0.001). Similarly, increases in SFCT were significantly in 0.37mW [22.63 μm (95%CI: 12.13, 33.34)], 0.60 mW [36.17 μm (95%CI: 24.37, 48.25)], and 1.20 mW [42.59 μm (95%CI: 23.43, 66.24)] than in the control group [-5.07 μm (95%CI: -10.32, -0.13)] (All P< 0.001). No significant differences (SE, AL, or SFCT) at evaluated times for LRL groups, however, a potential trend in figures suggests higher power links to improved efficacy within limits. No adverse events were observed.
LRL effectively controlled myopia progression at 0.37 mW, 0.60 mW, and 1.20 mW. Despite no significant power differences, a trend indicates higher power’s potential effectiveness. More extensive samples and longer follow-ups are vital for optimal LRL power determination.
Copyright © 2023. Published by Elsevier Inc.
