Diabetic eye complications are not only common, but often many patients go blind due to failure to take timely and effective treatment. Many patients with diabetic eye disease can be found in the clinic almost every day and are seen late, losing the opportunity for early treatment. It is important for any diabetic patient to have regular eye examinations and not to go to the doctor only when they feel that they have visual impairment or other eye discomfort. As with other complications of diabetes, early detection and early treatment are crucial. In fact, diabetes causes a wide range of damage in the eye. The common ones are diabetic retinopathy, referred to as glycoretinopathy, as well as diabetic cataract, optic nerve damage, macular degeneration, acute or chronic intraocular infections, vitreous hemorrhage, and secondary glaucoma. All of these lesions can cause blindness, so special attention should be given to both diabetic patients and diabetic physicians. Diabetic retinopathy is one of the most serious microvascular complications in diabetic patients and a major cause of blindness, which will be specifically addressed later in the lecture. Cataracts are a common eye disease in which the lens of the eye loses its transparency. Although cataracts can occur in middle-aged and elderly people without diabetes, diabetes can promote the development and progression of cataracts, especially in states where long-term hyperglycemic toxicity persists. Refractive changes of the eye are also frequent abnormalities in diabetic patients. Patients often feel blurred vision, mostly short-lived or transient, associated with dramatic fluctuations in blood glucose, manifesting as myopia during hyperglycemia and farsightedness when blood glucose drops more rapidly from high to low. This lesion can return to normal within a few weeks of intensive treatment for diabetes. The incidence of glaucoma is also significantly higher in diabetic patients. The onset of primary open-angle glaucoma may be related to sclerosis of the anterior chamber angle trabeculae and poor outflow of atrial fluid due to diabetes mellitus. Neovascular glaucoma occurs mostly in those with diabetic proliferative retinopathy. Ocular neuropathy: Damage to the oculomotor nerve is a diabetic vascular neuropathy, and ocular muscle paralysis often occurs suddenly. Among them, oculomotor nerve injury is the most common, manifesting as ptosis, limited eye movement, diplopia, etc.; followed by abducens nerve, manifesting as extraocular muscle paralysis. Oculomotor nerve injury generally has a good prognosis, but the course of the disease may last more than 8 weeks. When the trophoblastic vessels of the optic nerve are damaged, a neuroinflammatory response can occur, manifested as optic papillary edema, and in advanced stages, optic nerve atrophy, clinically manifested as varying degrees of visual acuity loss or even complete blindness. Autonomic neuropathy in the eye can lead to impaired regulation of the pupil’s light reflex and maladaptation to dark and bright light; it can also lead to impaired regulation of lacrimal secretion and dry eyes or easy tearing. Iris erythema is due to vasodilatation and neovascularization of the iris surface, which can extend further into the anterior chamber angle and form adhesions, and can lead to hemorrhagic secondary glaucoma because the walls of the neovascularization are thin and prone to rupture. Other diabetic patients are prone to conjunctival microaneurysms, subconjunctival hemorrhage, retinal lipemia, vitreous lesions, etc. Diabetic eye disease is a variety of complications caused by diabetes in the eye, just as diabetes can cause various kinds of damage to the heart, brain, liver, gallbladder, kidney, gastrointestinal, bladder, skin, mouth, bones, muscles, etc. in the large scope of the whole body, it can cause damage to vision, eye pressure, eyelids, conjunctiva, cornea, iris, anterior chamber, ciliary body, lens, vitreous, etc. in the small scope of the eye, especially retinal damage. Therefore, when it comes to prevention and treatment, treating diabetes is fundamental and treating eye damage is symptomatic, and in most cases requires close cooperation between the diabetologist and the ophthalmologist, working together.