Morphometric Analysis of the Optic Nerve Using MRI in Normal vs. Glaucoma Patients

Background: Glaucoma, a leading cause of irreversible blindness, is characterized by progressive optic nerve damage, primarily affecting retinal ganglion cells and axons. Objective: To assess and compare MRI-derived optic nerve measurements in POAG patients and healthy controls, and to evaluate the diagnostic accuracy and reliability of these measurements. Methods: A total of 85 participants (45 POAG patients and 40 healthy controls) were included in this prospective observational study. MRI scans were performed using a 3T MRI scanner with high-resolution T2-weighted fat-suppressed sequences. Optic nerve measurements were taken at three posterior levels (3 mm, 6 mm, and 9 mm). Results: The POAG group exhibited significantly smaller OND (mean 2.38 ± 0.22 mm) and ON-CSA (mean 4.51 ± 0.81 mm²) compared to the control group (OND: 2.62 ± 0.24 mm, ON-CSA: 5.39 ± 0.90 mm²), with p-values < 0.001 for both. The SASW was significantly wider in the POAG group (2.55 ± 0.28 mm) compared to controls (2.27 ± 0.27 mm, p = 0.003). The diagnostic accuracy of OND and ON-CSA was high, with AUC values of 0.83 and 0.81, respectively. The combination of OND and ON-CSA yielded an AUC of 0.88, indicating excellent diagnostic potential. Intra-rater and inter-rater reliability were excellent, with ICC values above 0.90. Conclusion: MRI-based morphometric analysis reveals significant reductions in optic nerve diameter and cross-sectional area in POAG patients, with a concomitant widening of the subarachnoid space. These findings support the use of MRI-derived metrics, particularly OND and ON-CSA, as reliable biomarkers for detecting glaucoma