Diabetic retinopathy: sonographically measured hemodynamic alterations in ocular, carotid, and vertebral arteries

To compare local ophthalmic blood flow changes with flow changes in carotid and vertebral arteries in diabetic patients with retinopathy of different grades.

Ten patients with proliferative or preproliferative retinopathy, 10 with mild retinopathy, and 10 matched controls were prospectively studied with ultrasound. Color and duplex Doppler imaging was used to quantitate blood flow in the central retinal arteries (CRA), ophthalmic arteries (OA), common carotid (CCA) and vertebral arteries (VA). Peak systolic velocity (PSV), mean velocity (MV), and resistance index (RI) in CRA, OA, CCA and VA, and volume flow (VF) were measured in CCA and VA.

There was a non-significant increase in the CRA and OA velocities in mild retinopathies, a decrease of about 30% in MV, and a slightly increased RI in proliferative or preproliferative retinopathies. There was a decrease of about 15% in the carotid MV and a 20% decrease in the vertebral MV and a decrease of about 30% in VF in the CCA and VA in severe retinopathies. The MV ratio of CRA/CCA was lower in the severe retinopathy group than in the controls.

The study showed a non-significant increase of ocular blood flow velocities in mild diabetic retinopathy and a significant decrease of flow velocities in severe diabetic retinopathy. This decrease in flow primarily seems to reflect the general decrease of blood flow in the cervical arteries.