Low-intensity red-light therapy in slowing myopic progression and the rebound effect after its cessation in Chinese children: a randomized controlled trial

PurposeTo investigate the effect of low-intensity red-light (LRL) therapy on myopic control and the response after its cessation.MethodsA prospective clinical trial. One hundred two children aged 6 to 13 with myopia were included in the LRL group (n = 51) and the single-focus spectacles (SFS) group (n = 51). In LRL group, subjects wore SFS and received LRL therapy provided by a laser device that emitted red-light of 635 nm and power of 0.35 ± 0.02 mW. One year after the control trial, LRL therapy was stopped for 3 months. The outcomes mainly included axial length (AL), spherical equivalent refraction (SER), subfoveal choroidal thickness (SFCT), and accommodative function.ResultsAfter 12 months of therapy, 46 children in the LRL group and 40 children in the SFS group completed the trial. AL elongation and myopic progression were 0.01 mm (95%CI: − 0.05 to 0.07 mm) and 0.05 D (95%CI: − 0 .08 to 0.19 D) in the LRL group, which were less than 0.39 mm (95%CI: 0.33 to 0.45 mm) and − 0.64 D (95%CI: − 0.78 to − 0.51 D) in the SFS group (p < 0.05). The change of SFCT in the LRL group was greater than that in the SFS group (p < 0.05). Accommodative response and positive relative accommodation in the LRL group were more negative than those in the SFS group (p < 0.05). Forty-two subjects completed the observation of LRL cessation, AL and SER increased by 0.16 mm (95%CI: 0.11 to 0.22 mm) and − 0.20 D (95%CI: − 0.26 to − 0.14 D) during the cessation (p < 0.05), and SFCT returned to baseline (p > 0.05).ConclusionsLRL is an effective measure for preventing and controlling myopia, and it may also have the ability to improve the accommodative function. There may be a slight myopic rebound after its cessation. The effect of long-term LRL therapy needs to be further explored.Trial registrationChinese Clinical Trial Registry: Chinese Clinical Trails registry: ChiCTR2100045250. Registered 9 April 2021; retrospectively registered. http://www.chictr.org.cn/showproj.aspx?proj=124250