Bilateral quantification of vascular density in diabetic patients using optical coherence tomography angiography

PurposeTo measure capillary vessel density (VD) using optical coherence tomography angiography (OCT‐A) in both eyes of diabetic patients and to evaluate its correlation with systemic risk factors.MethodsA total of 103 eyes of 61 diabetic patients underwent OCT‐A imaging (RTVue‐XR Avanti; Optovue, Fremont, CA, USA). The control group included 92 eyes of 46 individuals without diabetes mellitus. In diabetic patients the duration of diabetes, insulin therapy, blood pressure, HbA1C, dyslipidemia and the presence of diabetic retinopathy was recorded. VD was examined in the central macula with a radius of 3 mm. The effect of risk factors on VD was assessed bilaterally using multivariable regression analysis.ResultsVessel density was significantly decreased in diabetic patients compared to controls (47.26 vs. 50.88%; p < 0.001). In control subjects, VD significantly decreased with age (r = −0.54; p < 0.001), while in diabetic patients VD was associated only with the duration of diabetes among the risk factors (r = ‐0.15/year, p = 0.03). VD was also significantly decreased in diabetic patients without clinically detectable diabetic retinopathy compared to control subjects (48.19 vs. 50.88%, p < 0.001). Between‐eye difference in VD were significantly higher in diabetic patients with retinopathy (4.46±2.95%) and without retinopathy (4.19 ± 2.40%) in comparison to the controls (2.74 ± 2.24%; p = 0.02 for both comparisons).ConclusionsSignificantly decreased retinal vessel density and increased between‐eye asymmetry can be measured in diabetic patients compared to control subjects even before the presence of clinically detectable diabetic retinopathy. While in control subjects vessel density decrease with aging, in diabetic patients both vessel density and between‐eye asymmetry are significantly associated with the duration of diabetes.