Alteration of retinal circulation in patients with type 2 diabetes by a laser Doppler velocimetry system

Abstract

Abstract: : Purpose: To evaluate retinal circulation in type 2 diabetic patients by a laser Doppler velocimetry (LDV) system. Methods: Using a LDV system (CLBF model 100; Canon, Tokyo, Japan), we evaluated the retinal vessel diameter (D), blood velocity (V) and retinal blood flow (F) in retinal arteriole in 126 eyes of 126 healthy volunteers (control group) and 176 eyes of 176 patients with type 2 diabetes. The patients with type 2 diabetes were classified into 3 groups: 106 eyes of 106 patients with no diabetic retinopathy (NDR), 49 eyes of 49 patients with background diabetic retinopathy (BDR), and 21 eyes of 21 patients with pre–proliferative diabetic retinopathy (PPDR). Results: There were no differences in patient ages and systemic blood pressure among the groups. The group–averaged values of D did not differ among the groups. On the other hands, the group–averaged values of V and F in both NDR and BDR group were significantly lower than that in the control (P<0.01). In contrast, there were no significant differences in D, V, and RBF between the control and PPDR groups. Conclusions:Our results indicate that the retina blood flow may be reduced in type 2 diabetic patients with no retinopathy and mild retinopathy and the decrease in blood velocity in retinal arteriole may be an important factor for the decrease in blood flow. In addition, the reduced retinal blood flow may tend to increase in pre–proliferative retinopathy.

Keywords: diabetes • clinical (human) or epidemiologic studies: risk factor assessment • clinical research methodology