Diabetes is caused by insufficient insulin due to the secretion of the pancreas, which prevents the body from metabolizing the sugar in the food it consumes normally, resulting in high blood glucose concentration. High blood glucose concentration damages the blood vessel wall, causing changes in the permeability of the vessel wall, and the cells of the vessel wall atrophy due to loss of water, resulting in narrowing of the blood vessels, loss of elasticity of the vessel wall, and sluggish blood flow. Complications of diabetes mostly occur in capillary-rich organs, among which retinopathy is a common complication of diabetes mellitus. Diabetic retinopathy is caused by the long-term attack of high blood glucose, resulting in impaired capillary circulation in the retina of the eye: blood flow is sluggish, tissues are hypoxic, capillary walls become degenerative and brittle, and microangiomas, punctate or lamellar hemorrhages, and cotton wool exudates appear in the retina at the posterior pole of the eye, resulting in vision loss. If left untreated at this time, the lesion will further develop. Neovascularization of the fundus choroid due to hypoxia can cause vitreous hemorrhage, reproductive retinopathy, and lead to blindness. The excellent antioxidant properties of lutein can significantly improve vascular resistance, restore the lost balance of osmotic pressure inside and outside the blood vessels, reduce vascular permeability, inhibit the leakage of substances from the blood vessels, ensure the integrity of the eye blood vessels, and allow the eyes to receive adequate blood supply. At the same time, lutein also inhibits the production of neovascularization in the choroid, reducing the risk of bleeding in the fundus. Li Xiaorong and Hu Bojie from the Eye Center of Tianjin Medical University did an experiment on observing the changes in serum lutein levels and visual function in a Chinese population after lutein supplementation to explore its effects on serum lutein levels and visual function in patients with diabetic retinopathy. Serum lutein concentrations were measured in 30 normal subjects and 30 patients with diabetic retinopathy. Serum lutein concentrations were significantly lower in patients with diabetic retinopathy, and serum lutein concentrations were significantly higher at different times before and after taking the drug. There were significant improvements in visual acuity and contrast sensitivity at different times before and after medication.