AR and diabetes mellitus: Several associations between AR and early diabetic retinopathy have been described in detail, including the localization of AR in the retina; the role for increased AR activity in retinal capillary cell loss and formation of acellular capillaries, capillary basement membrane thickening, increased vascular permeability, and disruption of the blood-retinal barrier; increased leukocyte adhesion to endothelial cells; neovascularization with advanced proliferative DR (as learnt from animal models of diabetes); and galactose feeding [189,190,191,192].