Long-term effect of repeated low-level red light therapy on myopia control: A systematic review and meta-analysis

INTRODUCTION: Myopia is a refractive error where distant objects are not clearly seen and appear blurred. Goal of this study was to evaluate long-term effectiveness of Repeated Low-Level Red Light (RLRL) therapy for children with myopia, which primarily focused on Axial length (AL) and Spherical Equivalent Refraction (SER) as primary endpoints.

METHODS: The research compared outcomes between RLRL treatment with Single Vision Spectacles (SVS) for childhood myopia management. We performed a systematic literature search in the PubMed, Embase and Cochrane databases using "Myopia" and " Repeated Low-Level Red Light ". Mean differences (MD) were estimated and the effects of therapies measured. Publication bias and heterogeneity analysis were carried out by Inverted Precision Effect Test-Precision Effect Estimate Standard Error (PET-PEESE) (and subsequent Search Sequential Analysis) and Tau test. Bayesian meta-analysis was performed using Jaffrey Amazing Statistical Package (JASP).

RESULTS: This meta-analysis comprised 1,714 participants: 824 in RLRL and 890 in SVS group. Pooled effect size for AL reduction was 0.953 ± 0.294, (95% credible interval (CI) 0.775 to 0.980). Pooled effect size for SER reduction was 1.521 ± 0.662 (95% CI 0.102 to 2.736). PET-PEESE analysis revealed no significant publication bias (p-value 0.407). Random effects models were employed for presence of significant heterogeneity (3.9 and 5.7 for AL; 5.7 for SER), alongside degree of variation (0.828 & 1.665) for Tau (τ), which estimates the between-study variance.

CONCLUSION: Long-term observations indicate that RLRL treatment significantly influences myopia management, leading to considerable reductions in both AL and SER. Additional research is essential to investigate potential long-term rebound effects.