Tract-based spatial statistical analysis of diffusion tensor imaging is a successful tool for the detection of cortical nerve fibre loss in primary open-angle glaucoma (POAG) patients, claims a recent paper.

, Department of Ophthalmology, Tongji Hospital, Shanghai City, China, devised a cross-sectional investigation consisting of 25 patients with POAG and 24 healthy control subjects.

All participants underwent thorough ophthalmological assessments, including cup-to-disc ratio, retinal nerve fibre layer thickness and a visual field test. The main outcome measures were diffusivity changes of the nerve fibres in the visual pathway, mean diffusivity and fractional anisotrophy. All measurements were compared with ophthalmological data.

Bilateral optic tracts and optic radiations in POAG patients demonstrated significantly decreased fractional anisotrophy and increased mean diffusivity, compared to the control group.

The fractional anisotrophy of the optic tracts and optic radiations consistently varied with cup-to-disc ratio, retinal nerve fibre layer thickness and visual function analysis, respectively.

There was no significant correlation between the mean diffusivity of the optic radiations and the ophthalmological measurements. But the mean diffusivity of the optic tracts correlated with the ophthalmological measurements.

Optic tracts and optic radiations of POAG patients revealed radiological evidence of neurodegeneration, which varied with optic disc damage and loss of visual function.

The abstract can be found in the journal 