Retinal hemodynamic changes in diabetic macular edema

Abstract

Abstract Purpose To report the 1 year prospective hemodynamic results in a cohort of patients with varying levels of risk for the development of diabetic macular edema (DME) and to correlate these parameters to systemic changes in blood pressure and diabetes control. Methods The sample comprised 4 groups. Group 1: 37 non‐diabetic controls; Group 2: 42 patients with no diabetic retinopathy (DR); Group 3: 38 patients with DR but no DME; Group 4: 27 patients with DME. Retinal arteriolar diameter, velocity, maximum‐to‐minimum (max:min) velocity ratio and flow were measured using the Canon Laser Blood Flowmeter. Blood pressure, blood and urine tests were taken and correlated to changes in retinal hemodynamics. A sub‐group of patients with progressive DR was analyzed separately. Results There was a trend for elevation of the max:min velocity ratio (p=0.060) with increasing risk of DME at baseline which was significant on follow‐up (p=0.020). Diameter decreased for all groups (p<0.056) except for patients with DME. Changes in retinal blood velocity, max:min velocity ratio and flow were correlated to blood pressure mostly in patients with DR and DME. Blood albumin level was negatively correlated to retinal blood velocity and flow in the DME group. Patients with progressive DME had elevated blood velocity and flow. Conclusion Patients with DME have a higher max:min velocity ratio. Changes in retinal hemodynamics were correlated to changes in blood pressure and were negatively correlated to changes in blood albumin. The results indicate a loss of vascular compliance with diabetes, particularly in patients with DME, and elevated retinal perfusion in patients with progressive DME.