Background: Glaucoma is a progressive optic neuropathy, which is characterized by degeneration of the retinal ganglion cells. The role of optic nerve head (ONH) microvascular network and vascular dysfunction has been investigated in the pathogenesis of glaucoma. Objective: The aim of the current work was to assess the correlation between visual field changes in primary open angle glaucoma (POAG), and the density of the radial vessels around the optic disc. Patients and Methods: One hundred eyes of fifty patients were enrolled in this prospective cross-sectional study. Patients were recruited from the Department of Ophthalmology, Al-Zahraa University Hospital from December 2018 to March 2020. They were divided into two groups, control group with normal functional and structural data, and glaucomatous group with POAG. Results: There were significant differences in all measurements among both groups, including visual field indices, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) parameters. The changes of peripapillary vessel density (PpVD) had strongly positive correlations with the mean deviation (MD), ganglion cell complex (GCC) thickness and retinal nerve fiber layer (RNFL) thickness, while had negative correlation with pattern standard deviation (PSD) and cup disc (C/D) ratio. Conclusion: Decreased PpVD was detected in the glaucomatous group. There were statistically significant correlations between visual field changes (changes of both MD and PSD) and PpVD where there were strongly positive correlations with the (MD), and negative correlation with PSD. This can add to the diagnosis of POAG. Also, it provided more information about the microvascular changes in the ONH and peripapillary retina in cases of POAG.