Diabetes mellitus is a group of lifelong metabolic diseases characterized by chronic hyperglycemia caused by multiple etiologies. Diabetes itself does not necessarily cause harm, but the long-term increase in blood sugar, macrovascular and microvascular damage and endanger the heart, brain, kidneys, peripheral nerves, eyes, feet, etc. According to the World Health Organization, diabetes complications up to more than 100 kinds of complications, is currently the most known complications of a disease. More than half of the deaths due to diabetes are due to cardiovascular and cerebrovascular causes, and 10% are due to nephropathy. Amputations due to diabetes are 10-20 times more common than non-diabetes. For this reason prevention of complications of diabetes is a vital social issue. In addition to frequent blood glucose checks, diabetic patients should have regular blood biochemistry checks, heart, brain and kidney function tests and eye fundus checks. Diabetic eye complications 1. Diabetic retinopathy retinal capillary lesions manifest as aneurysms, hemorrhagic spots, hard exudates, absorbent cotton spots, venous bead-like, intraretinal microvascular abnormalities, and macular edema. Extensive ischemia causes retinal or optic disc neovascularization, anterior retinal hemorrhage, and detachment of the retina by traction. Patients have severe visual impairment. Diabetes can cause two types of retinopathy, proliferative and non-proliferative retinopathy. Diabetic retinopathy is one of the major blinding eye diseases. 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 and cause vitreous hemorrhage. Compared to non-proliferative retinopathy, proliferative retinopathy is more dangerous to vision and can lead to severe vision loss or even complete blindness. 2. The initial onset of diabetes-related uveitis is mostly acute anterior uveitis with sudden onset of eye pain, photophobia and tearing. Examination reveals ciliary congestion, a large number of fine dusty posterior corneal deposits, anterior chamber flash glow, anterior chamber inflammatory cells, and in a few patients, a large amount of fibrinous exudate in the anterior chamber, or even pus accumulation in the anterior chamber, which eventually leads to complications such as posterior iris adhesions, iris neovascularization, concurrent cataracts, and secondary glaucoma. 3.Diabetic cataract Diabetic cataract, occurs in adolescent diabetic patients whose blood sugar is not well controlled. It develops rapidly and can even develop into cloudiness and complete cloudiness within days, weeks or months; it starts with typical white dot-like or snowflake-like cloudiness under the anterior and posterior capsules and rapidly expands into complete cataract, which is more common in the later subcapsular pole; it is often accompanied by refractive changes and shows myopia when blood sugar is elevated and farsightedness when blood sugar is lowered.