Adjunctive repeated low-level red-light therapy enhances structural outcomes in optical myopia control: A meta-analysis

BACKGROUND: Repeated low-level red-light (RLRL) therapy, a photobiomodulation approach for myopia control, has shown potential in modulating choroidal and axial structures. Recent studies have combined RLRL with optical interventions such as orthokeratology (OK) and defocus incorporated multiple segment (DIMS) spectacles. However, the efficacy and safety of these combinations remain unclear. This study synthesized current evidence on RLRL combined with optical interventions for pediatric myopia control. METHODS: A systematic search of PubMed, EMBASE, Cochrane Library, Web of Science, CNKI and Wanfang Data was conducted up to July 14, 2025. Randomized and cohort studies comparing RLRL combined with OK or DIMS versus monotherapy were included. Primary outcomes were axial length (AL), spherical equivalent refraction (SER), and subfoveal choroidal thickness (SFChT). Fixed- or random-effects models were used based on heterogeneity. Risk of bias was assessed with ROB2 and ROBINS-I. RESULTS: Eight studies were included. Compared with optical monotherapy, combination therapy was associated with reduced axial elongation, slower SER progression, and greater increases in SFChT. Structural changes were observed as early as 1 month and persisted through 12 months. No significant differences were detected in short-term ocular surface adverse events. However, heterogeneity and regional concentration of data were noted. CONCLUSIONS: Adjunctive RLRL therapy may enhance optical myopia control effects, particularly in reducing axial elongation and increasing choroidal thickness, possibly through choroidal modulation. These findings should be viewed as early biological signals, not definitive evidence of long-term superiority. Larger multicenter randomized trials with extended follow-up are needed to confirm durability, safety, and dose-response characteristics.