Ocular Gene Therapy Targeting Retinal Angiogenesis and Vascular Leakage: Translational and Clinical Evidence from a Systematic Review and Meta-Analysis

Retinal diseases driven by pathological angiogenesis and vascular leakage, including neovascular age-related macular degeneration and diabetic retinopathy, impose substantial visual and treatment burdens because current anti-vascular endothelial growth factor (anti-VEGF) therapy requires repeated intravitreal administration. Ocular gene therapy can provide durable intraocular expression of therapeutic proteins and sustained pathway-level disease control. This systematic review and meta-analysis was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) and conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. PubMed, Scopus, Web of Science, ScienceDirect, and the Cochrane Library were searched from inception to April 21, 2026. Eligible studies included preclinical, in vitro, and clinical investigations of gene-based interventions targeting retinal angiogenesis, vascular permeability, or related anatomical and treatment-burden outcomes. Random-effects meta-analyses were performed using standardized mean differences (SMDs), mean differences (MDs), and logit event rates. Twenty-five studies were included. Preclinical gene therapy significantly reduced pathological neovascularization, with a pooled standardized mean difference (SMD) of −1.16 (95