STRICT METABOLIC CONTROL AND RETINAL BLOOD-FLOW IN DIABETES-MELLITUS

The effects of strict diabetic control on retinal haemodynamics were s tudied to elucidate whether such effects are associated with retinopat hy changes. In 28 patients with poorly controlled insulin dependent di abetes mellitus and non-proliferative retinopathy, retinal haemodynami cs were investigated at baseline, 5 days, 2 months, and 6 months after the institution of strict diabetic control using the bidirectional la ser Doppler velocimetry technique and monochromatic fundus photography . Changes in retinal blood how measured in a major retinal vein (Q) on the fifth day of strict diabetic control correlated significantly wit h changes in retinopathy level observed at the end of the 6 months of this study (rank correlation 0.65, p<0.01). On the fifth day of strict diabetic control, 16 out of 20 eyes that showed no progression (NP) o f retinopathy at the end of the study had decreases in Q, whereas six out of eight eyes that showed progression (P) had increases in Q. The difference in these changes in Q between P and NP eyes was statistical ly significant (one way analysis of variance, p=0.001). No significant changes in Q were detected at 2 months or 6 months. Following the ins titution of strict diabetic control, no significant changes in time we re detected in the regulatory response to 100% oxygen breathing charac terised as the percentage decrease in Q at 4-6 minutes of oxygen breat hing (analysis of variance, p=0.36). Changes in Q following institutio n of strict diabetic control are associated with progression of retino pathy. Measurements described in this study may help identify diabetic patients at risk of progression when their metabolic control is impro ved.