Efficacy of red light for myopia control from age 2 to 24 with diverse treatment periods: A real-world study

• In the real-world study involving 2,825 participants aged 2-24 across 20 hospitals and up to 36 months of follow-up, repeated low-level red light therapy (RLRL) showed sustained efficacy and favorable safety. • Adverse events were infrequent (0.21%) throughout the study, although OCT-based retinal structural changes were observed in some cases. • Axial elongation persisted in pre-school children, whereas the older age group and larger baseline axial length showed a higher likelihood of axial shortening. : To explore the age-specific efficacy, long-term outcomes and safety of RLRL therapy in real-world clinical settings. : In the prospective, multi-center, real-world cohort, 2,825 participants who underwent low-level red light (RLRL) therapy for myopia control were recruited from 20 hospitals in China. Axial length (AL), spherical equivalent refraction (SER), best-corrected visual acuity (BCVA), compliance, and adverse events were recorded at baseline and each visit. Follow-up duration was stratified into four periods (≤ 6, 7-12, 13-24, and 25-36 months). Efficacy was estimated as the annual changes of AL using longitudinal linear mixed-effect model. : AL increased slightly in children aged 2-7 and 8-12 years, but remained stable in those aged 13-24 years. During the first 6 months, annual axial length (AL) changes reached -0.18, -0.29, and -0.72 mm for the 2-7, 8-12, and 13-24 group, and shifted to 0.14, 0.06, and -0.01 mm with 25-36 months of treatment. Multivariable analyses identified larger baseline AL (β=0.72, p0.05). Adverse events were infrequent (0.21%). : RLRL therapy is an effective and well-tolerated approach for myopia control across a broad age range and up to 36 months, showing sustained efficacy and favorable safety in real-world clinical settings.