MEASUREMENT OF RETINAL MICROCIRCULATION AND MACROCIRCULATION IN PATIENTS WITH DIABETES-MELLITUS WITH SCANNING LASER OPHTHALMOSCOPY

1. The new scanning laser ophthalmology technique (SLO) allows us to quantify retinal haemodynamics. A digital image analysing system was used for the measurement of retinal ''macro-'' and ''microcirculation''. 2. Arm-retina-time (ART), arterio-venous passage time (AVP) and mean dye velocity (MDV) were quantified for the assessment of retinal ''macrocirculation''. Measurements of capillary blood flow velocities (v), perifoveal intercapillary areas (PIA) and foveal avascular zones (FAZ) were performed to quantify retinal ''microcirculation''. 3. Twenty-four healthy volunteers and thirty-three insulin-dependent diabetic patients with no or minimal retinopathy were included in the study. The results show significant disturbances of retinal haemodynamics (''macro-'' and ''microcirculation'') in diabetic patients with no or mild retinopathy. 4. The decrease of micro- and macrocirculatory blood flow velocities in combination with an extension of morphologic parameters of perifoveal intercapillary areas and foveal avascular zone may explain the chronic hypoxia in diabetics. 5. The new scanning laser angiography combined with digital image analysis provides a reliable and reproducible technique for blood flow measurements in retinal arterioles and venules and perifoveal capillaries. Especially determination of retinal ''microcirculation'' may help to monitor the progress of diabetic maculopathy.