Diabetic retinopathy is the most important ocular complication of diabetes and is a cause of blindness. Appropriate metabolic control and photocoagulation therapy can delay or prevent blindness caused by diabetic retinopathy. Diabetes and its complications Diabetic nephropathy, diabetic foot and other retinopathies are covered in the medical guide, please click on the link to view. The pathogenesis of retinopathy is related to the duration and control of diabetes. The pathogenesis is based on a number of unspecified factors that can cause retinal circulation disorders during the course of diabetes, in addition to abnormal carbohydrate metabolism, including thickening of the capillary basement membrane, loss of mural cells, decreased fibrin function of the vessel wall, excessive blood viscosity secondary to changes in plasma proteins, abnormal red blood cell viscosity, and stagnation of blood flow. Diabetes can cause two types of retinopathy – proliferative and non-proliferative retinopathy . Diabetic retinopathy is one of the major blinding eye diseases. Diabetic retinopathy can occur with or without insulin therapy. Diabetic damage to the retina is mainly due to increased blood glucose, thickened walls and increased permeability of the small blood vessels, making them more susceptible to deformation and leakage. The severity of diabetic retinopathy and the degree of vision loss are related to the control of blood glucose levels and the duration of diabetes. The duration of disease is particularly important, as diabetic retinopathy usually develops after at least 10 years of diabetes. In non-proliferative (simple) retinopathy, rupture and leakage of small retinal capillaries occur. At the site of each enlarged capillary rupture, a small capsule with hemoprotein deposits forms. These changes can be detected by the doctor on fundus examination. Fluorescein angiography (a diagnostic method in which the doctor injects dye into the patient’s vein and takes fundus photographs as the dye reaches the retina with the bloodstream) can help determine the extent of the lesion. Early non-proliferative retinopathy does not cause vision loss, but small retinal hemorrhages can cause localized visual field loss, and if the hemorrhage involves the macula, vision will be significantly reduced. In proliferative retinopathy, retinal damage stimulates the growth of new blood vessels. Neovascular growth can be harmful to the retina, causing fibroplasia and sometimes retinal detachment. Neovascularization can also grow into the vitreous or cause vitreous hemorrhage. Proliferative retinopathy is more dangerous to vision than non-proliferative retinopathy, and can lead to severe vision loss or even complete blindness. Prevention and treatment The most effective way to prevent diabetic retinopathy is to control diabetes and maintain blood glucose at normal levels. Patients should have routine annual eye exams for 5 years after the diagnosis of diabetes, so that retinopathy can be detected early and treated early to preserve vision. One treatment option is laser retinal photocoagulation, in which a laser beam is directed at the neovascularization and photocoagulated to destroy the neovascularization and close the leaking vessels. Because the retina contains no nerves that feel pain, laser photocoagulation is not painful. If the vascular damage has caused extensive bleeding and has entered the vitreous, surgical removal (vitrectomy) may be required. Visual acuity may improve after vitrectomy. The vitreous is gradually replaced by intraocular fluid.