White Matter Abnormalities and Correlation With Severity in Normal Tension Glaucoma: A Whole Brain Atlas-Based...

Area of Science:

• Neuroimaging
• Ophthalmology
• Neurology

Background:

• Normal tension glaucoma (NTG) is a progressive optic neuropathy.
• White matter (WM) integrity may be affected in NTG.
• Diffusion tensor imaging (DTI) is a sensitive technique for assessing WM microstructure.

Purpose of the Study:

• To detect whole brain white matter (WM) injury in normal tension glaucoma (NTG) patients using DTI.
• To analyze correlations between DTI parameters and glaucoma indices.

Main Methods:

• Atlas-based DTI analysis was used to measure fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).
• DTI parameters were compared between NTG subgroups (mild, moderate, severe) and normal controls (NC).
• Relationships between DTI parameters and glaucoma indices (visual field mean deviation, RNFL thickness) were assessed.

Main Results:

• NTG patients showed significantly decreased FA and AD, and increased MD and RD in specific WM regions (posterior thalamic radiation, sagittal stratum, cingulum-hippocampus, fornix/stria terminalis) compared to NC.
• DTI parameters correlated with visual field mean deviation (MDVF) and retinal nerve fiber layer (RNFL) thickness.
• A tipping point was observed between MDVF and DTI parameters, and between MDVF and RNFL thickness.

Conclusions:

• Atlas-based DTI can identify WM damage in NTG patients, particularly in regions related to visual function.
• DTI analysis can aid in investigating disease progression and pathological changes in NTG.
• White matter impairment and RNFL thinning precede detectable visual field loss in NTG.