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

Abstract

Purpose: To investigate the effect of low-intensity red-light (LRL) therapy on myopic control and the response after its cessation.

Methods: A 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.

Results: After 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).

Conclusions: LRL 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 registration: Chinese Clinical Trial Registry: Chinese Clinical Trails registry: ChiCTR2100045250. Registered 9 April 2021; retrospectively registered. http://www.chictr.org.cn/showproj.aspx?proj=124250.

Keywords: Axial length; Lag of accommodation; Low-intensity red-light; Myopia; Rebound effect.