Nowadays, the incidence of diabetes is on the rise and younger. Since diabetes is a chronic disease and most patients are not sufficiently aware of the dangers of diabetes, their blood glucose is poorly controlled or fluctuates high and low. Due to the increase of blood sugar, it causes abnormalities in carbohydrate, protein and fat metabolism and gradually develops vascular lesions and metabolic disorders and complications in several organs of the body, including the eyes, kidneys, nervous system, heart and blood vessels and other tissues, among which the lesions occurring in the eyes are called diabetic eye disease. Currently, many patients are not fully aware of diabetes and its ocular complications. Some patients do not find out they have diabetes until they visit an ophthalmologist with diabetic eye disease, or they know they have diabetes but do not come to an ophthalmologist until they have eye problems. Diabetic eye diseases include diabetic cataract, diabetic retinopathy, diabetic optic neuropathy (anterior ischemic optic neuropathy), refractive error, ocular motor nerve palsy with diplopia, and iridocyclitis. All of these complications affect the patient’s visual function to a greater or lesser extent, and the one that causes permanent damage to visual function is the severe diabetic retinopathy, which must be taken seriously. Therefore, once you find out that you have diabetes, you must go to the hospital ophthalmology department for a comprehensive examination, including bare eye vision and corrected visual acuity, intraocular pressure, slit lamp microscopy for cataracts, iridocyclitis, iris neovascularization, and dilated pupil examination for diabetic retinopathy and diabetic optic neuropathy. In the future, receive regular eye examinations as required by the doctor. To reduce the occurrence of eye complications, the key is to control blood glucose in a stable and lasting manner, and to control blood pressure and blood lipids at the same time.