Microvascular changes in diabetes mellitus (DM) may occur before the onset of clinically detectable diabetic retinopathy (DR). A cross-sectional study published in Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy evaluated peripapillary retinal and choroidal microvasculature using swept-source optical coherence tomography angiography (SS-OCTA) in individuals with DM without clinical signs of DR.

The study included 211 participants categorized by diabetes duration, including non-diabetic controls and groups with DM duration of less than 5 years, 5-10 years, and 10 years or more. SS-OCTA was used to measure superficial capillary plexus peripapillary vascular density (SCP pVD), peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell-inner plexiform layer (GCL-IPL) thickness, and choroidal parameters. Linear regression analysis identified factors associated with SCP pVD.

Compared with controls, individuals with DM showed lower SCP pVD (31.39% vs 33.56%, p<0.05), with a progressive decline corresponding to longer disease duration (B=−0.205, p<0.001). pRNFL thickness decreased with increasing duration of DM, and differences in GCL-IPL thickness were observed across groups. Peripapillary choroidal vascularity index (CVI) was consistently lower in DM groups. SCP pVD was independently related to diabetes duration, pRNFL thickness, choroidal thickness, and hypertension.

These findings indicate that SS-OCTA detects early microvascular and structural changes in DM before clinical DR. Further studies are required to determine the role of these parameters in early screening and risk stratification.