Background and Objectives: Despite the growing amount of new research, the pathophysiology of glaucoma remains unclear. The aim of this study was to determine the relationship between intracranial pressure (ICP), ocular blood flow and structural optic nerve parameters. Materials and Methods: A prospective clinical study was conducted involving 24 patients with open-angle glaucoma and 25 healthy controls. Routine clinical examination was performed. Swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA) images were taken (DRI-OCT Triton, Topcon). The vessel density (VD) values of the ONH were calculated around the optic nerve head (ONH). An orbital Doppler device (Vittamed 205, Kaunas, Lithuania) was used for non-invasive ICP measurements. Color Doppler imaging (CDI) (Mindray M7, Shenzhen, China) was used for retrobulbar blood flow measurements in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCAs). Results: ICP was 8.35 ± 2.8 mmHg in the glaucoma group and 8.45 ± 3.19 mmHg in the control group (p = 0.907). In the glaucoma group, the VD of the superficial vascular plexus in the inferior-nasal (NI) sector of the ONH showed a correlation with ICP (r = 0.451, p = 0.05). In contrast, the control group exhibited weaker correlations. CRA peak systolic velocity (PSV) demonstrated significant moderate correlations with VD in multiple retinal layers, including the avascular retina layer in the temporal (T) sector (r = 0.637, p = 0.001). Conclusions: Lower ICP was significantly associated with the lower VD of the superficial plexus layer in the inferior-nasal sector in the glaucoma group, with the control group exhibiting weaker correlations in all sectors. Further longitudinal studies with larger sample sizes are needed to establish associations between intracranial pressure, ocular blood flow and ONH parameters.

Background and Objectives: Glaucoma is a neurodegenerative disease involving retinal ganglion cell loss, optic nerve damage and alterations within the central visual pathway. We evaluated visual cortex activity using functional magnetic resonance imaging (fMRI) in patients with primary open-angle glaucoma (POAG) and its associations with retinal structural and microvascular parameters assessed using optical coherence tomography (OCT) and OCT angiography (OCTA). Materials and Methods: This prospective clinical study included 19 patients with POAG and 18 healthy controls. All participants underwent ophthalmological examination, standard automated perimetry (Humphrey 24–2 SITA Standard), swept-source OCT, OCTA of the optic nerve head (ONH) (DRI-OCT Triton, Topcon, Tokyo, Japan), and visual stimulation fMRI (3T Siemens Magnetom Skyra, Siemens Healthineers, Erlangen, Germany). Retinal nerve fiber layer (RNFL) thickness, vessel density (VD), and visual cortex activity were compared between groups. Associations were assessed using Pearson’s or Spearman’s correlation according to data distribution, with Benjamini–Hochberg false discovery rate correction. Unadjusted p and adjusted q values are reported. Results: RNFL thickness was reduced in POAG patients in all four sectors. VD was lower in every sector of the superficial and deep plexus (all q < 0.05), as was outer retinal signal. Choriocapillaris findings were heterogeneous. RNFL thickness correlated with choriocapillaris VD in two of three corresponding nasal sectors, in POAG patients only. Visual cortex activation was lower in POAG patients (p = 0.046; Hedges’ g = −0.68, 95% CI −1.34 to −0.01), but not after adjustment for age (p = 0.086). No association between VD and cortical activity survived FDR correction. Conclusions: In POAG, choriocapillaris VD tracked RNFL thickness in corresponding nasal sectors, an association not detected in controls. Reduced cortical activation did not persist after adjustment for age, and no retinal–cortical microvascular association was found. These exploratory findings suggest that distinct retinal vascular layers may carry different pathophysiological information and require confirmation in larger cohorts.