Retrobulbar Hemodynamic Alterations in Diabetes Mellitus: Doppler Evaluation of the Ophthalmic and Central Retinal Arteries

Background: Diabetes mellitus causes microvascular alterations that contribute to the development of diabetic retinopathy. Hemodynamic changes in retrobulbar circulation may occur before clinically detectable retinal damage. Purpose: This study aimed to compare Doppler hemodynamic indices of the ophthalmic artery (OA) and central retinal artery (CRA) between diabetic participants and non-diabetic controls. Materials and methods: This cross-sectional observational study included 76 participants (38 diabetic participants and 38 non-diabetic controls), comprising 152 eyes analyzed at the eye level. Color Doppler imaging was used to measure peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), and systolic/diastolic (S/D) ratio in the OA and CRA. Group comparisons were performed using an independent samples t-test, with statistical significance set at p < 0.05. Results: Diabetic participants demonstrated significantly higher vascular resistance in retrobulbar arteries. OA-RI was significantly higher in diabetic participants (0.80 ± 0.03) than in non-diabetic controls (0.71 ± 0.01; p < 0.001). CRA-RI was similarly elevated (0.70 ± 0.04 vs. 0.62 ± 0.01; p < 0.001). Retrobulbar blood flow velocities were significantly reduced in diabetic participants, including OA-PSV (19.38 ± 2.71 vs. 29.18 ± 1.42 cm/s; p < 0.001) and OA-EDV (3.84 ± 1.04 vs. 8.49 ± 0.53 cm/s; p < 0.001). CRA-PSV (9.02 ± 1.23 vs. 13.28 ± 0.64 cm/s; p < 0.001) and CRA-EDV (2.87 ± 0.82 vs. 5.05 ± 0.33 cm/s; p < 0.001) were also significantly reduced. S/D ratios were significantly elevated in both vessels among diabetic participants. Conclusions: Diabetes is associated with increased vascular resistance and reduced blood flow velocities in the OA and CRA. These findings suggest that color Doppler imaging may help identify early hemodynamic alterations in the ocular circulation associated with diabetic retinal disease.