Similar as the occurrence of diabetic nephropathy, diabetic retinopathy is also a result of microvascular changes in patients with long history of diabetes. Initially, high concentration of blood glucose damages endothelial cells of retina, one main component of blood-retinal barrier, which impairs the oxygen supplement to retina as a result of chronic hypoxia. In order to compensate the hypoxic condition, massive capillary proliferates in retina as progression of disease as called proliferative diabetic retinopathy. Without intensive blood glucose control, vision impairment even blindness will be the end point of the process, characterized by cotton wool spots, flame hemorrhages, or dot-blot hemorrhages under funduscopy.
