Visual field defect positively correlated to optic radiation damage in glaucoma

The authors hypothesized that the fractional anisotropy (FA) value of optic radiation decreases as the visual field defect progresses. To test this hypothesis, they used FA diffusion-tensor MRI to study the axonal architecture of the optic radiation in 29 patients with glaucoma and 19 healthy controls, and examined the correlation between the FA value of the optic radiation and the corresponding visual field defect.

They observed significantly lower FA values for the bilateral anterior and posterior optic radiations of patients with glaucoma than for those of the healthy controls. Furthermore, FA values of the entire optic radiation correlated with the degree of visual field defect. Age and FA value were negatively correlated in the control group.

They propose that diffusion-tensor MRI is an objective method for estimating the progression of alterations in the central nervous system that accompany glaucoma. However, they note that presently the clinical use of diffusion-tensor MRI for glaucoma has several limitations, including low specificity, high cost and the requirement of a long examination period.