There was a decrease in both the average thickness of the retinal nerve fiber layer (RNFL) and the circumpapillary vascular density (cpVD) in various regions of the eye in patients with preperimetric glaucoma (PPG). Both cpVD and RNFL thickness exhibited similar diagnostic efficacy in early glaucoma, even though RNFL loss was more pronounced in preperimetric eyes. Researchers sought to analyze the associations between vascular and structural characteristics in PPG and early glaucoma and to assess the variations in circumpapillary and macular vascular density. For this cross-sectional analysis, investigators enrolled a total of 27 patients, each of whom had PPG in 1 eye and early primary open-angle glaucoma in the other, in addition to a control group of 27 eyes belonging to 27 healthy volunteers. Optical coherence tomography angiography (OCTA) imaging was performed on all participants. AngioVue OCTA measurements of the vascular system and the retinal nerve fiber layer/macular ganglion cell complex were acquired in a single scan. An investigation of cpVD was conducted in 8 different industries. The diagnostic area under the curve (AUC) was calculated to determine how well the test performed. The area under the receiver operating characteristic curve of 0.853 for average RNFL thickness and 0.753 for whole-image vascular density indicate similar diagnostic performance in preperimetric eyes. While cpVD only varied in the nasal inferior and nasal superior sectors (P=0.001 and 0.041, respectively), RNFL thickness was significantly reduced in all quadrants (P<0.001-0.003) except the temporal quadrant in PPG eyes. Perifoveal macular vascular parameters differed in all quadrants (all P<0.05) in early glaucoma eyes, while cpVD differed substantially from controls in all sectors except the inferotemporal, temporal inferior, and superior temporal sectors. It was shown that cpVD and RNFL thickness were highly linked in the superior, nasal, and temporal quadrants (r=0.664, 0.698, and 0.649, respectively, P<0.001) and moderately correlated in the inferior quadrant (r=0.450, P<0.001). The involvement of the RNFL is helpful in diagnosing and monitoring PPG, but the alteration in nasal cpVD is also significant. In the early stages of glaucoma, macular vascular parameters and macular ganglion cell complex take on a more central role in glaucoma monitoring. More long-term research is required to establish OCTA’s role in glaucoma diagnosis and monitoring.