Brain morphometric alterations along the visual pathway in nonarteritic anterior ischemic optic neuropathy: a voxel-based morphometry study.

PURPOSE: To investigate brain morphometric changes in patients with non-arteritic anterior ischemic optic neuropathy (NAION) using voxel-based morphometry (VBM) and to explore their associations with structural and functional ophthalmic parameters.

METHODS

This retrospective, cross-sectional study included 15 patients with NAION and 15 healthy controls. All participants underwent high-resolution 3.0-Tesla brain magnetic resonance imaging. Whole-brain VBM was performed using the Computational Anatomy Toolbox (CAT12) implemented in Statistical Parametric Mapping (SPM12) to assess gray and white matter volume differences between groups. Ophthalmic evaluation included best-corrected visual acuity, visual field mean deviation, retinal nerve fiber layer thickness, and ganglion cell-inner plexiform layer thickness measured by optical coherence tomography. Correlation analyses were performed to evaluate the relationships between brain morphometric measures and ophthalmic parameters.

RESULTS

Compared with controls, patients with NAION exhibited reduced gray matter volumes in the limbic lobe, cuneus, occipital lobe, temporal lobe, middle temporal gyrus, parietal lobe, and frontal lobe at an exploratory voxel-level threshold (p < 0.001, uncorrected). Increased gray matter volumes were observed in the bilateral cerebellum, while increased white matter volumes were identified in the right cerebellum and posterior cerebellar lobe. No significant correlations were identified between brain morphometric measures and ophthalmic parameters, time since onset, or visual function (all p > 0.05). None of the observed gray or white matter clusters remained statistically significant after family-wise error (FWE) correction for multiple comparisons.

CONCLUSIONS

Preliminary evidence suggests that patients with NAION may exhibit brain morphometric alterations involving visual pathway-related cortical regions and the cerebellum. These exploratory findings raise the possibility that central nervous system changes in NAION may extend beyond isolated optic nerve pathology. However, because none of the observed clusters survived family-wise error (FWE) correction for multiple comparisons, these findings should be considered exploratory and require confirmation in larger studies.