Adult-onset Coats disease: A systematic review and meta-analysis of imaging biomarkers and targeted therapies.

Coats disease diagnosed in adulthood is a rare idiopathic retinal telangiectatic vasculopathy that may differ in phenotype from childhood-diagnosed cases. This systematic review synthesizes current evidence to characterize its clinical spectrum, imaging features, treatment outcomes and underlying mechanisms, with a focus on immunovascular pathways. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines, PubMed, Scopus and Web of Science were searched through October 2025 for studies including patients ≥18 years with confirmed Coats disease. Clinical and imaging findings, treatment strategies and outcomes were extracted and narratively synthesized. When possible, random-effects meta-analysis was performed. Thirty-five studies comprising 240 patients (250 eyes) were included. Disease presentation was predominantly unilateral and diagnosed at Shields Stage 2 or 3. Laser photocoagulation and anti-vascular endothelial growth factor (VEGF) agents were the most frequently described therapies, with anatomical stabilization or regression of exudation reported in approximately half of treated eyes across heterogeneous studies, and better outcomes in earlier stages. Visual acuity was stabilized or improved in 57.1% of treated eyes, while recurrence occurred in 19.3%. Multimodal imaging consistently identified peripheral telangiectasia, lipid exudation and localized capillary nonperfusion. Aqueous cytokine profiling in small cohorts has reported elevated inflammatory mediators (e.g. interleukin [IL]-6 and IL-1β) in some adults, suggesting that inflammatory signalling may contribute to blood-retina barrier dysfunction and macular oedema alongside VEGF-related permeability. Current evidence supports Coats disease diagnosed in adulthood as a chronic telangiectatic retinal vasculopathy with frequent macular involvement. Therapeutic outcomes appear to favour individualized, imaging-guided combination strategies and prospective studies with standardized endpoints are needed to refine management.