Effectiveness of repeated low-level red light in myopia prevention and myopia control.

ABSTRACT

BACKGROUND/AIMS: To compare the effects of repeated low-level red light (RLRL) treatment on axial length growth and refractive error changes in myopic and premyopic children. METHODS: Subjects were assigned randomly to four subgroups myopia-RLRL group (M-RL), myopia-control group (M-C), premyopia-RLRL group (PM-RL) and premyopia-control group (PM-C). Subjects in the RLRL group completed a 12-month treatment composed of a 3 min RLRL treatment session twice daily, with an interval of at least 4 hours, for 7 days per week. Visits were scheduled before and at 1-month, 3-month, 6-month, 9-month and 12-month follow-up after the treatment. Repeated-measures analysis of variance was used to compare the spherical equivalent refractive errors (SE) and axial length (AL) changes between the groups across the treatment period. RESULTS: After 12 months of treatment, in the myopia group, SE and AL changes were -0.078±0.375 D and 0.033±0.123 mm for M-RL and -0.861±0.556 D and 0.415±0.171 mm for M-C; in the premyopia group, the progression of SE and AL was -0.181±0.417 D and 0.145±0.175 mm for PM-RL and -0.521±0.436 D and 0.292±0.128 mm for PM-C. PM-RL indicated a lower myopia incidence than PM-C (2.5% vs 19.4%). Additionally, the percentage of AL shortening in the M-RL was higher than that in the PM-RL before the 9-month follow-up. CONCLUSION: RLRL effectively delayed myopia progression in children with myopia and reduced the incidence of myopia in premyopic children. Moreover, RLRL exhibited a stronger impact on myopic children compared with premyopic individuals.