ObjectiveTo observe the lipid metabolism characteristics of type 2 diabetes mellitus (T2DM) patients with different levels of blood glucose control and preliminarily analyze their relationship with diabetic retinopathy (DR). MethodsA retrospective clinical study. From January 2019 to January 2024, 232 T2DM patients who underwent fundus examination in Department of Ophthalmology of Yichang Central People’s Hospital were included in the study. Based on the glycated hemoglobin A1c (HbA1c) test results, patients were divided into blood glucose standard group and blood glucose non standard group, with 100 and 132 cases respectively. Based on the results of fundus fluorescein angiography, patients were divided into non DR (NDR) group and DR group, with 89 and 143 cases, respectively. 100 healthy individuals who underwent physical examinations during the same period were selected as the control group. The thickness of peripapillary retinal nerve fiber layer (pRNFL) around the optic disc, the blood flow density of radial peripapillary capillaries (RPC) around the optic disc, and the thickness of ganglion cell complex (GCC) in the upper and lower parts of the optic disc and macular area were measured by optical coherence tomography angiography instrument. Fully automated biochemical analyzer was used to detect serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and HbA1c. After adjusting for confounding factors, multiple linear regression model was used to analyze the correlation between HbA1c and blood lipids. Multiple logistic regression analysis was conducted to investigate the correlation between TG, HDL-C, and the occurrence of DR. ResultsCompared with the control group, both the blood glucose standard group and the blood glucose non standard group had higher levels of HbA1c (F=8.115), TC (F=4.373), TG (F=20.220), and LDL-C (F=12.271), and lower levels of HDL-C (F=6.349), with statistically significant differences (P＜0.05). Compared with the blood glucose standard group, patients in the blood glucose non standard group had higher levels of serum HbA1c (t=3.531), TC (t=2.561), TG (t=6.418), LDL-C (t=7.880), and lower levels of HDL-C (t=5.152), with statistically significant differences (P＜0.05). Correlation analysis showed that HbA1c was positively correlated with TC, TG, and LDL-C (P＜0.05), and negatively correlated with HDL-C (P＜0.05). Multiple logistic regression analysis showed that TG, LDL-C, and HDL-C were independent risk factors for the occurrence of DR (Ptrend＜0.05). Compared with the NDR group, the DR group had thinner GCC and pRNFL thickness in the upper part of the optic disc, and lower overall and RPC blood flow density in the upper part of the optic disc, with statistically significant differences (t=4.964, 2.406, 2.685, 2.404; P＜0.05). Correlation analysis results showed that TG, LDL-C, HDL-C, HbA1c were correlated with GCC thickness, pRNFL thickness, and RPC blood flow density (P＜0.05). ConclusionsThe higher the blood glucose level in T2DM patients, the more likely they are to experience dyslipidemia. TG, LDL-C, and HDL-C are independent risk factors for the occurrence of DR. Abnormal blood lipids and blood glucose levels in T2DM patients can affect retinal nerves, blood vessels, and function.