Contributor: Gordon K. Klintworth
Diabetic retinopathy is the retinopathy that develops in persons with diabetes mellitus. It is divided into non-proliferative, pre-proliferative and proliferative types. There is a characteristic microangiopathy with prominent leaky capillary microaneurysms. Other manifestations of diabetic retinopathy include macular edema [edema - macula], lipid rich exudates [hard exudate] and "blot and dot" hemorrhages (mostly in inner nuclear layer and outer plexiform layer of the retina) , an obliteration of parts of the retinal capillary network, a preferential loss of pericytes in the capillaries, cotton-wool spots and a progressive retinal neovascularization [neovascularization - retina]. In proliferative diabetic retinopathy an extensive network of delicate newly formed blood vessels surrounded by fibrous and glial tissue invade the vitreous from the region of the optic disc or the inner retina. Fragile new vesels break through the retinal internal limiting membrane and grow on the inner retina and posterior surface of the detached vitreous [neovascularization - vitreoretinal]. They rupture producing vitreous hemorrhage [hemorrhage - vitreous]. The neovascularization is associated with a proliferation and migration of astrocytes, which grow around the new vessels to form delicate white veils (gliosis). Visual loss from diabetic retinopathy usually takes years to develop, but eventually occurs from tractional detachment of the macula and other parts of the retina as well as from vitreous hemorrhage. Visual loss usually takes years to develop, but eventually occurs from tractional detachment of the macula and other parts of the retina as well as from vitreous hemorrhage. Diabetic retinopathy is not related to the cause of the diabetes, but like other delayed lesions in diabetes mellitus, it is an outcome of diabetic microangiopathy. Diabetic retinopathy is typified by a characteristic microangiopathy.