Spontaneous High Frequency Diameter Oscillations of Larger Retinal Arterioles Are Reduced in Type 2 Diabetes Mellitus

Abstract

Diabetic retinopathy is characterized by morphological changes in the retina secondary to disturbances in retinal blood flow. Vasomotion is a mechanism for regulating blood flow by spontaneous oscillations in the diameter of retinal resistance arterioles, and has been shown to be disturbed outside the eye in diabetic patients. Therefore, the purpose of the present study was to characterize spontaneous oscillations in the diameter of retinal arterioles in normal persons and in persons with different severity of diabetic retinopathy. Video recordings of the retina were performed in 19 normal persons and three matched groups of type 2 diabetic patients with no retinopathy, mild retinopathy, and diabetic maculopathy. Continuous recordings of a larger retinal arteriole during rest and during an increase in the arterial blood pressure induced by isometric exercise were subjected to power spectrum analysis of spontaneous oscillations in vessel diameter. During rest the oscillations in the diameter of retinal arterioles with high frequencies were significantly reduced in patients with diabetic retinopathy. Increased arterial blood pressure did not change the oscillations in normal persons, but further reduced the oscillations in diabetic patients. Spontaneous high frequency oscillations in the diameter of larger retinal arterioles are reduced in type 2 diabetic patients, and are further reduced during an increase in the arterial blood pressure. The finding may reflect changes in the vascular walls of importance for diagnosing and predicting the visual prognosis in patients with diabetic retinopathy.