Retinal Blood Flow in T1DM Patients

Abstract

Abstract: : Purpose: Controversy exists as to the effect of T1DM on retinal blood flow. Methods: The goal of the current research is to determine and compare arterial diameter, blood velocity and retinal blood flow of 100 T1DM patients. A non–invasive Doppler laser blood flowmeter (Canon Laser Blood Flow 100) was used to collect the data. Measurements were taken of the superior–temporal artery one–disc diameter from the optic nerve head. Arterial diameter (micrometers), blood velocity (mm/sec) and blood flow (micoliters/min) were collected. Subjects: A modified Airlie House diabetic retinopathy classification was used. Grades 1 and 2 were classified as mild to no retinopathy. Grades 3 and 4 were classified as moderate retinopathy, and grades 5 and 6 as severe retinopathy. Due to media opacities and/or fixation problems, in 24 patients we were only able to get a good reading in one eye. The majority (155/176) of the T1DM patient’s eyes that we were able to collect data on fell into the mild to no retinopathy and the moderate groups (75/176 and 80/176 respectively). 21 eyes were classified as severe retinopathy. Results: Mean values for blood velocity and flow in retinal arteries were shown to decrease as the severity of the diabetic retinopathy increased (table 1). From the mild to no retinopathy group to the moderate group arterial diameter decreased. The diameter then increased for the severe retinopathy group (table 1). Conclusions: Preliminary analyses indicate that retinal arterial velocity and blood flow is decreased as diabetic retinopathy progresses. Arterial diameter decreased from no mild or moderate and then increases with severe retinopathy. Laser Doppler Blood flowmetry is a tool to understand structural and functional alterations in the diabetic retinal vasculature. Table 1: Blood flow data. 

Keywords: diabetes • diabetic retinopathy • blood supply