Ocular perfusion abnormalities in diabetes.

PURPOSE To review the role of ocular perfusion in the pathophysiology of diabetic retinopathy, one of the leading causes of irreversible blindness in the industrialized world. METHODS We carried out a Medline search of the literature published in English or with English abstracts from 1966 to 2000 using various combinations of relevant key words. RESULTS Hyperglycaemia leads to a wide variety of vascular abnormalities at the microvascular and macrovascular levels, including abnormal autoregulation. CONCLUSION Three major aspects of ocular perfusion in diabetic retinopathy require additional investigation. Firstly, the precise mechanisms that link elevated glucose to dysfunction of retinal vascular cells need to be identified. Secondly, those factors that lead to both capillary dropout and to angiogenesis, twin processes that are linked to tissue hypoxia and lead to excess perfusion, increased risk of extravascular leakage and frank haemorrhage, must be carefully delineated. Finally, once specific knowledge of disease fundamentals has been amassed, tests of therapies to reverse or prevent these pathological processes can move forward.