Diabetes can cause a variety of eye diseases, but the most common and the one that affects vision the most is diabetic retinopathy, which develops when long-term high blood sugar damages the blood vessels in the eye. Diabetic patients are 25 times more likely to go blind due to DR than normal people. Worldwide diabetic retinopathy has become one of the major blinding eye diseases. The early onset and severity of DR in diabetic patients is directly related to good blood glucose control, blood lipids and blood pressure. Statistics show that diabetic retinopathy is 7% in patients with diabetes <10 years and 63% in patients with diabetes >15 years. Among patients with diabetes >10 years, 100% of those with poor glycemic control had DR and severe lesions. DR occurred in 61% of those with good glycemic control. Diabetic retinopathy is divided into six stages, the first three being non-proliferative (also called simple or background) and the last three being proliferative. Stages I, II, III, IV, V, and VI have mild to severe disease, with visual impairment increasing phase by phase and treatment difficulty increasing phase by phase. Stages I and II are mainly about controlling blood sugar. In stage III, on the basis of blood sugar control, fundus laser can improve retinal hypoxia to make retinal neovascularization regress. In stage IV, blood glucose is controlled and treated symptomatically with other drugs, and fundus laser treatment is performed in time after the absorption of blood in the vitreous. If serious blood accumulation is not absorbed for a long time, vitrectomy will be performed. In stage V and VI, strict control of blood glucose and early vitrectomy will be performed. At present, it is impossible to prevent the occurrence of diabetic retinopathy fundamentally, but diabetic retinopathy can be prevented or reduced. Therefore, if you have diabetes, strict blood sugar control and regular fundus examination are the fundamental measures to prevent diabetic retinopathy from causing blindness. Fundus laser is the main method to prevent blindness from diabetic retinopathy, and its purpose is to control the disease and reduce the risk of blindness.