Spectral characteristics of light and their association with myopia progression in children: A systematic review protocol

The rising prevalence of myopia, particularly among children, has emerged as a major global public health concern. Emerging evidence indicates that the spectral composition of light may play a critical role in regulating ocular growth and influencing the onset and progression of myopia. However, the available evidence is characterized by substantial heterogeneity in study design, exposure assessment, and myopia-related outcome measures, making it difficult to draw consistent conclusions. This systematic review aims to identify and evaluate specific spectral profiles of light associated with measurable reductions in myopia progression. To achieve a comprehensive synthesis, evidence from observational human studies and clinical trials will be systematically reviewed. A systematic literature search will be conducted across major databases including PubMed, Scopus, Web of Science, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, Cochrane Register of Controlled Trials (CENTRAL), and Google Scholar, without restrictions on language or publication period using defined keywords. Eligible studies will include those examining the relationship between light wavelength, spectral irradiance, temporal dynamics, and myopia progression. Two reviewers will independently perform study selection, data extraction, and quality appraisal using validated tools appropriate to each design, including the Cochrane Risk of Bias 2 (RoB 2), Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I), Joanna Briggs Institute (JBI) checklists, and the National Heart, Lung, and Blood Institute (NHLBI) quality assessment tools. Data will be synthesized narratively, and a meta-analysis conducted where study comparability permits. Taken together, this systematic review protocol outlines a rigorous and transparent approach to consolidate current evidence on the influence of light spectra on myopia development, identify methodological limitations, and outline research priorities to guide future clinical trials, and public health strategies aimed at mitigating childhood myopia progression globally. This review is registered in PROSPERO [CRD420251171027].