A chronic, pathological complication associated with diabetes mellitus, where retinal damages are incurred due to microaneurysms in the vasculature of the retina, progressively leading to abnormal blood vessel growth, and swelling and leaking of fluid from blood vessels, resulting in vision loss or blindness. Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.