The goal of this observational study is to observe the formation and development of the non-perfusion area of diabetic retinopathy in the posterior area of the retina in type 2 diabetes patients aged 18-75 years old, who can cooperate with all examinations and sign informed consent, clinical myopathy examination and Optos 7 field of vision with mild than severe NPDR, and no other exclusion indicators.The main questions it aims to answer are whether posterior retinal non-perfusion area occurs earlier than peripheral non-perfusion area and whether the rate of non-perfusion area expansion is a risk factor for the progression of diabetic retinopathy. Participants will have protocol-specific follow-up examinations at 1, 2, 3, 4, and 5 years (± 3 months). Additional visits are made as required by the study and the patient's condition. The contents of follow-up examinations are: History of other diseases, medications being used, eye diseases, surgeries, treatments, height, weight, and blood pressure. Best corrected vision, logarithmic visual acuity chart. Tupai OCTA, 24×20mm range, 6×6mm range scan. Optos fundus imaging, color and no red light images. Fundus fluorescence angiography (only preliminary examination for the first time found mild to moderate NPDR patients, who have been angiographed in the past, only at the 5th year, or as required by the condition). Glycosylated hemoglobin. Creatinine, urea, glomerular filtration rate. Total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol. Urinary microalbumin/urinary creatinine ACR. Microvisual field.