AIM: To analyze the clinical utility and value of the ultra-wide-field swept-source optical coherence tomography angiography(UWF-SS-OCTA)technique in changes of blood flow density and thickness in the central and peripheral regions of the retina and choroid in patients with nonproliferative diabetic retinopathy(NPDR)with or without diabetic kidney disease(DKD).METHODS: Cross-sectional study. Totally 50 cases(50 eyes)of diabetes mellitus(DM)that visited our hospital between June 2023 and June 2024 were included. They were divided into three groups: NPDR combined with DKD group(DKD group, n=20), NPDR without DKD group(NDKD group, n=20), and DM without retinopathy group(DM group, n=10, which served as control). In order to investigate the impact of DKD on ocular microangiopathy in NPDR patients, the retina and choroid within 24 mm×20 mm of the scan were separated into central and peripheral areas using the 3×3 nine-grid partition option that comes with UWF-SS-OCTA, and the parameters were then quantitatively assessed.RESULTS:The central and peripheral blood flow density of the choroidal capillary layer(CCP)was statistically significant between the DM group and the DKD group(t=3.93, P=0.0003; t=3.34, P=0.0016), and between the NDKD group and the DKD group(t=-3.06, P=0.003; t=-2.55, P=0.013), but there was no statistically significant difference between the DM group and the NDKD group(t=1.44, P=0.157; t=1.26, P=0.21). The mid-large choroidal vessel(MLCV)showed a progressive decline in central and peripheral blood flow density in the DM, NDKD, and DKD groups(F=13.74, 19.03, all P<0.0001). The DM, NDKD, and DKD groups saw a progressive decrease in central and peripheral choroidal thickness(CT; F=10.72, P=0.0001; F=13.12, P<0.001).CONCLUSION:CCP, MLCV, and CT can be used as visual indicators to identify impaired renal function in patients with NPDR. UWF-SS-OCTA can support the development of precise and noninvasive monitoring and treatment technology for diabetic ocular microangiopathy, while also offering a scientific foundation for the joint management of DR and DKD.