Colour Doppler imaging of the ocular circulation in diabetic retinopathy

PURPOSE: To measure blood flow velocity in the ophthalmic artery (OA) and central retinal artery (CRA) in patients with diabetic retinopathy. SUBJECTS AND METHODS: 62 age-matched subjects divided into 3 groups: nondiabetic controls (n=17); diabetics with no clinical retinopathy or background changes (n=24); diabetics with either pre-proliferative or proliferative retinopathy (n=21). Colour Doppler imaging was performed on supine patients by one masked observer using the Acuson 128 machine. RESULTS: There was a statistically significant (p<0.05) decrease in both the peak systolic velocity (PSV 0.073 m/s) and end diastolic velocity (EDV 0.014 m/s) of the central retinal artery in the pre-proliferative/proliferative group compared to the no retinopathy/background retinopathy group (PSV 0.096 m/s, EDV 0.024 m/s) and the control group (PSV 0.142 m/s, EDV 0.029 m/s). The resistance index of the ophthalmic artery was significantly increased in both the preproliferative/proliferative (0.81) and the no retinopathy/background group (0.81) compared to controls (0.72). CONCLUSION: Reduced blood flow velocity was found in the CRA of diabetic patients and appeared to become further reduced with the progression of retinopathy. This suggests that monitoring with Colour Doppler imaging may have predictive power in identifying those at greatest risk of developing sight threatening proliferative disease. The resistance index of the OA was increased in diabetics compared to controls.