Poor diabetic control is associated with an increased risk of diabetic retinopathy, and there is a particularly increased risk in insulin-dependent (type 1) patients for the development of proliferative diabetic retinopathy There is good evidence that hyperperfusion is an important factor in the evolution of diabetic retinopathy. This hyperperfusion is worse in those with poor diabetic control. The increased blood flow associated with high glucose interferes with autoregulation, and this further increases flow, damaging the endothelial lining of the blood vessels and leading to worsening of the retinopathy.