ObjectiveTo investigate the correlation of retinal blood vessel density with blood pressure and retinal thickness in the macular region of glaucoma. MethodsA retrospective study. From March 2019 to March 2022, 100 glaucoma patients of 100 eyes (glaucoma group) and 100 healthy people of 100 eyes (control group) diagnosed in Department of Ophthalmology of Luoyang First People's Hospital were included in the study. The patients in the glaucoma group were subdivided into the early, intermediate, and late groups based on the average visual field defect value, which were 38, 32, and 30 cases, respectively. Optical coherence tomography angiography was used to scan the macular area of the examined eyes in a 3 mm×3 mm area. The software automatically divided the retina within 3 mm of the macular central concavity into 2 concentric circles centered on the macular central concavity, which were the central concave area with a diameter of 1 mm and the paracentral concave area with a diameter of 1-3 mm. The blood flow density and retinal thickness of the superficial retinal capillary plexus in the nasal, temporal, inferior, and superior quadrants of the retina within 3 mm of the macula were measured. Blood pressure was measured at the brachial artery using an electronic sphygmomanometer. Comparisons between two groups were made by independent samples t test, and comparisons between multiple groups were made by one-way analysis of variance. Correlations between retinal blood flow density and blood pressure and retinal thickness were analyzed by Spearman's correlation analysis. ResultsThe retinal blood vessel density in the central fovea, parafoveal, inferior, and superior macular areas in the glaucoma group were lower than that in the control group, and with the aggravation of the disease, the retinal blood vessel density in the central fovea, parafoveal, inferior and superior macular areas gradually decreased; the retinal thicknesses in the foveal, parafoveal, inferior, and superior macular areas in the glaucoma group were lower than those in the control group, and with the aggravation of the disease, the retinal thicknesses in the foveal, parafoveal, inferior, and superior macular areas gradually decreased, the differences were statistically significant (P＜0.05). Systolic and diastolic blood pressure were higher in the glaucoma group than in the control group, and they increased gradually as the disease worsened (P＜0.05). Spearman's correlation analyses showed that in glaucoma patients, the density of retinal blood vessels in the macular central plexus, paracentral plexus, and inferior and superior retinas was positively correlated with retinal thickness in the corresponding areas and negatively correlated with blood pressure (P＜0.05). ConclusionThe density of retinal blood vessels in the macular central plexus, paracentral plexus, and inferior and superior retinas are positively correlated with retinal thickness in the corresponding areas and negatively correlated with blood pressure.