Low Retinal Vascular Complexity May Flag Higher Cardiovascular Risk

This research investigates the relationship between retinal microvascular complexity and cardiovascular health, highlighting how changes in retinal vessel patterns, measured by fractal dimension, could serve as noninvasive indicators of cardiovascular outcomes. The above images (from a different study) show the difference between high (top image) and low (bottom image) fractal dimension. Photo: Chelvin CA, et al. Nephrology Dialysis Transplantation. 2010; 25(7):2252–2258. Click image to enlarge. A new systematic review and meta-analysis suggests that reduced retinal vascular fractal dimension (FD)— a measure of the complexity of blood vessels—may serve as an early indicator of cardiovascular disease (CVD) risk. The findings, recently published in BMC Ophthalmology, add weight to ongoing efforts to tap into the strengths of retinal imaging as a noninvasive window into systemic vascular health.The research team reviewed 14 studies (eight cohort, six cross-sectional) published through June 2025 that evaluated associations between FD and cardiovascular outcomes. Across pooled analyses, lower fractal dimension was associated with a higher likelihood of developing CVD. When FD was treated as a continuous measure, data showed that lower retinal vascular complexity was linked to a higher incidence of cardiovascular disease.When analyzed categorically, individuals in the lower FD group at baseline faced a greater risk of developing CVD than those with higher fractal dimension. Reduced FD was also associated with an increased likelihood of already having CVD, and sensitivity testing confirmed these findings. When arterioles and venules were examined separately, the researchers found that the relationship between decreased arteriolar fractal dimension and CVD risk remained; however, venular FD showed no significant association with cardiovascular risk.Overall, this research revealed a connection between reduced fractal dimension and the incidence and prevalence of cardiovascular disease. “The decreased retinal microvascular FD was significantly associated with the CVD risk, especially in retinal arteriole,” the study authors wrote in their BMC Ophthalmology paper. “The findings of this study supported that fractal dimension may be a potential marker of CVD risk including stroke and coronary heart disease. Noninvasive FD measurement may act as an adjunct to existing cardiovascular disease risk stratification, facilitating early screening and diagnosis of individuals at elevated CVD risk.”Click here for the journal source. Lian Y, Li G, Liu H, et al. Fractal analysis of retinal microvasculature and cardiovascular outcome: a systematic review and meta-analysis. BMC Ophthalmol. 2025;25:668. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.