Article 4

Background: Primary Open Angle Glaucoma (POAG) is a prevalent neurodegenerative disorder marked by the progressive degeneration of the retinal nerve fiber layer (RNFL) and retinal ganglion cells (RGCs), attributable to ischemia. The non-invasive optical coherence tomography angiography (OCTA) method provides a new way to diagnose and treat glaucoma by detecting and quantifying vascular and clinical structural characteristics. In regard to glaucoma staging system II visual field, this research intends to identify ischemia alterations in primary open-angle glaucoma patients using optical coherence tomography (OCT) angiography. Patients and methods: Group A consisted of 40 eyes from 40 glaucomatous patients, while Group B consisted of 40 eyes from 40 healthy, non-glaucomatous volunteers in this prospective observational single-center hospital-based cross-sectional case-control clinical trial. Visual acuity, intraocular pressure, gonioscopy, optical coherence angiography, visual field, and data were gathered and evaluated from all subjects. Results: Each group is balanced in terms of age and gender. In terms of mean UDVA and CDVA, there were highly significant differences between the two groups (P-value <0.001). Mean intraocular pressure (IOP) did not differ significantly between the two groups (13.59 ± 2.11 and 15.08± 0.67, respectively; P-value = 0.06). For both the superior and inferior RNFL thickness, there was a highly significant difference between the cases and controls according to optical coherence tomography assessment (OCT) (P-value = 0.002 and 0.001, respectively), in relation to OCTA.A statistically significant difference was seen with respect to the whole picture, the upper hemifield, and the lower hemifield VD (P-value <0.001 for all components). There were robust positive associations found between one set of MD visual field measurements and a number of OCT and OCTA outcome metrics, notably the OCT inferior RNFL thickness. However, considerable negative associations were seen between PSD in the visual field and both the superior and inferior RNFL thickness in the OCT (r=0.21, 0.68; P-value = 0.005 and 0.003, respectively). Conclusion: In patients with POAG, a higher negative MD and higher positive PSD values in the VF are associated with thinner RNFL thickness, larger OCTA FAZ size and perim, lower retinal perfused vessel density, and reduced retinal blood flow, all of which point to the presence of ischemic retinal changes.