Diabetes is a systemic disease, and long-term poor blood glucose control will affect multiple systems throughout the body and produce a variety of acute and chronic complications. The effects of high blood glucose on the eyes mainly include the following: 1. When the short-term elevation of blood glucose is obvious, it will cause changes in atrial osmotic pressure, leading to blurred vision in patients. 2. Diabetic retinopathy, long-term poor blood glucose control, will develop diabetic retinopathy, leading to bleeding and exudation in the fundus, neovascularization, and the formation of new blood vessels. In severe cases, retinal detachment is formed, leading to blindness of patients. Diabetic retinopathy is a unique ocular complication of diabetes and is related to microangiopathy.3. Cataracts, long-term high blood glucose may lead to clouding of the crystal and metabolic cataract.4. Other, long-term poor blood glucose control in diabetic patients may also lead to macular degeneration, optic nerve atrophy, glaucoma and other ocular lesions.