Photobiomodulation in animal models of ophthalmic disease: protocol for systematic review and meta-analysis of morphological, visual function, and inflammatory outcomes.

BACKGROUND: Despite accumulating preclinical evidence supporting the therapeutic efficacy of photobiomodulation (PBM) in ophthalmic disease models, the systematic evaluation and quantitative synthesis of these findings remain underexplored. This protocol aims to comprehensively synthesize existing studies by categorizing outcome measures into morphological, visual, and inflammatory domains according to ophthalmic pathology. The primary objective of this study is to evaluate the therapeutic efficacy of PBM for ophthalmic diseases and to consolidate the current body of preclinical evidence. METHODS: This study will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) guidelines. We will include controlled preclinical studies using animal models of four predefined ophthalmic conditions: age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, and corneal injury. A systematic search will be conducted across relevant electronic databases without restrictions on publication date. Outcomes will be categorized into three domains, morphological, visual functional, and inflammatory, to evaluate the efficacy of PBM in ophthalmic diseases. Two independent reviewers will perform study selection, data extraction, and risk of bias assessment using the SYRCLE tool. Where appropriate, meta-analyses will be conducted using random-effects models, with heterogeneity assessed using I2 statistics. Subgroup and sensitivity analyses will be performed to explore sources of variability. DISCUSSION: This systematic review aims to integrate and assess the quality of current evidence regarding PBM's efficacy across morphological, visual functional, and inflammatory outcomes. Findings will contribute to future trial designs and support the development of standardized protocols for PBM applications in ophthalmology. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251054002, PROSPERO CRD420251054002.