Evaluate Specific Retinal Layers in DR to Understand Vascular Changes

Retinal vascular geometry could become a dual-purpose screening tool for both diabetic eye disease and systemic cardiovascular risk assessment. Microvascular changes advance with the severity of DR. At the same time, complexity as measured by fractal dimension diminishes, as these images from the study show. Photo: Fathimah, et al. Int J Retina Vitreous. 2025;11(1):64. Click image to enlarge. Retinal vessel tortuosity is one of the early signs of vascular changes in retinopathy cases. OCT angiography (OCT-A) provides depth-resolved in vivo observation of the retinal and choroidal microvasculature quickly and noninvasively, and it is able to detect vascular changes in the eyes of patients with diabetes even without clinical diabetic retinopathy (DR). By using OCT-A and analyzing parameters such as vessel tortuosity and fractal dimension, a recent study based in Indonesia revealed significant differences in these retinal measurements of the deep capillary plexus (DCP) among diabetic patients based on DR severity.This retrospective study analyzed medical records and OCT-A images of patients with and without DR. The researchers analyzed 96 patients (161 eyes) with a mean age of 52.7. Compared with patients without DR, vessel tortuosity was significantly higher in all DR groups: mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR and proliferative DR (PDR). Fractal dimension of the superficial capillary plexus showed no significant difference among the groups and a significantly lower fractal dimension of the DCP compared to the groups without DR. Fractal dimension is a measure of the complexity and branching pattern of the retinal vasculature; it quantifies the degree of self-similarity or irregularity in the branching patterns of blood vessels in the retina. While fractal dimension is a robust marker for established DR progression, the researchers noted that other biomarkers or techniques might better capture very early changes in mild NPDR.“This finding suggests a potential threshold effect, where the extent of microvascular damage and capillary nonperfusion in mild NPDR may not be extensive enough to induce a statistically significant alteration in the overall fractal architecture of the DCP,” they wrote in their paper, which was published in International Journal of Retina and Vitreous.Regarding the observed decrease in vessel tortuosity in severe stages of DR, particularly in the proliferative DR group where panretinal photocoagulation is commonly performed, the researchers believed that this interpretation warrants careful consideration. “While an increase in vessel tortuosity is typically associated with earlier DR progression due to factors like altered hemodynamic forces, inflammation and angiogenesis, the subsequent decrease in advanced stages following PRP is unlikely to represent a true restoration of pristine vascular geometry,” the study authors wrote.The study concluded that its findings underscore the necessity of evaluating specific retinal layers to gain deeper insights into the vascular changes linked to DR. If validated in larger studies, retinal vascular geometry could become a dual-purpose screening tool for both diabetic eye disease and systemic cardiovascular risk assessment.Click here for the journal source. Fathimah FSN, Ari Widjaja S, Sasono W, et al. Retinal vessel tortuosity and fractal dimension in diabetic retinopathy. Int J Retina Vitreous. 2025;11(1):64.