Does microaneurysm count reflect severity of early diabetic retinopathy?

In a group of 55 insulin-dependent diabetic patients with early diabetic retinopathy, microaneurysm counts from fluorescein angiograms were related to the level and severity of retinopathy derived by grading eight standard stereo color photographs as used in the Early Treatment of Retinopathy Study (ETDRS). All patients were studied at 0, 8, and 24 months. Significant correlations were present between both "definite" and "possible" microaneurysm count and retinopathy level of the eye studied and the mean retinopathy level of the two eyes, at all three time intervals, (P less than 0.05-less than 0.001). Similarly, there were significant correlations between microaneurysm counts and severity of the following lesions: microaneurysms and haemorrhages, cotton-wool spots (P less than 0.05-less than 0.001); to a lesser degree, severity of hard exudates (P less than 0.1-less than 0.001) and intraretinal microvascular abnormalities (P not significant-less than 0.001). There was no correlation between microaneurysm count and venous abnormalities (as at no time were there more than 11 eyes with any venous abnormality). We conclude that microaneurysm counts from fluorescein angiograms accurately reflect the severity of important signs in early diabetic retinopathy.