Retinal microvascular alterations assessed by OCTA in metabolic liver disease: insights into systemic microvascular dysfunction—a systematic review and semi-quantitative synthesis

Background Metabolic liver disease, historically characterized as nonalcoholic fatty liver disease (NAFLD) and recently redefined as metabolic dysfunction-associated steatotic liver disease (MASLD), has emerged as a global public health crisis. It is increasingly recognized not merely as a liver-specific pathology, but as a complex multisystemic disorder strongly associated with widespread systemic microvascular dysfunction. The retina, sharing similar anatomical and physiological features with the systemic microcirculation, provides a unique, * in vivo * window for non-invasive vascular assessment. Methods A systematic review with semi-quantitative synthesis was conducted in strict adherence to the PRISMA guidelines. We comprehensively searched the PubMed, Embase, and Cochrane Library databases for relevant studies published from inception to March 2026. Studies employing optical coherence tomography angiography (OCTA) to evaluate the macular microvasculature in patients with metabolic liver disease were included. Study quality was rigorously appraised using the Newcastle–Ottawa Scale (NOS). Results A total of 7 cross-sectional and retrospective studies encompassing approximately 520 participants met the stringent inclusion criteria. Across the included cohorts, a consistent and statistically significant reduction in retinal vessel density (VD) was observed. Notably, this vascular rarefaction was predominantly localized within the deep capillary plexus (DCP). Furthermore, an abnormal enlargement of the foveal avascular zone (FAZ) was consistently reported in patients with metabolic liver disease compared to matched healthy controls, indicating subclinical macular ischemia. Conclusion Metabolic liver disease is significantly associated with early retinal microvascular alterations detectable by OCTA, preceding visually significant ocular symptoms. These subclinical findings highlight a profound pathological link between hepatic steatosis and systemic microvascular dysfunction. OCTA metrics, particularly DCP vessel density and FAZ area, may serve as novel, non-invasive biomarkers for identifying patients at high risk for systemic vascular complications.