Retinal neurodegeneration: early pathology in diabetes

Normal vision depends on the normal function of retinal neurons, so vision loss in diabetes must ultimately be explained in terms of altered neuronal function. However, to date relatively little attention has been paid to the impact of diabetes on the neural retina. Instead, the focus of most resear ch has been primarily on retinal vascular changes, with the assumption that they cause altered neuronal function and consequently vision loss. An incr easing body of evidence suggests that alterations in neuronal function and viability may contribute to the pathogenic mechanisms of diabetic retinopat hy beginning shortly after the onset of diabetes. This view arises from neu rophysiological, psychometric, histopathological and biochemical observatio ns in humans and experimental animals. The collective evidence from past an d recent studies supports the hypothesis that neurodegeneration, together w ith functional changes in the vasculature, is an important component of dia betic retinopathy. The authors invite other investigators to include the ne ural retina as a component of their studies so that the pathogenesis of dia betic retinopathy can be understood more clearly.