In 42 type II diabetic patients with nonproliferative diabetic retinopathy the arm-retina time (ART) and arteriovenous passage time (AVP) were measured by means of videofluorescein angiography. Glycosylated hemoglobin (HbAlc) as a parameter of longterm diabetic control and the blood glucose level were determined. The ART in the diabetics was similar to the ART of normals and the AVP was significantly prolonged. HbAlc level ranged between 5.6 and 12.2% (8.6 +/- 1.7%) and the blood glucose level between 4.5 and 22.9 mmol/l (11.4 +/- 4.5 mmol/l). Significant correlations were found between AVP and blood glucose (r = 0.37) and between AVP and HbAlc (r = 0.49). No correlation was found neither between ART and blood glucose nor between ART and HbAlc. A multiple stepwise regression analysis shows that of both investigated parameters HbAlc is the predicting variable for AVP. These results show that in diabetic patients the retinal blood flow is more influenced by the longterm diabetic control than by the blood glucose level at the time of examination.