Positive correlation between the degree of visual field defect and optic radiation damage in glaucoma patients

We evaluated optic radiation (OR) damage in patients with glaucoma by using fractional anisotropy (FA) of diffusion-tensor magnetic resonance imaging. We studied 29 patients with glaucoma and 19 healthy controls. Regions of interest were placed over the bilateral anterior and posterior ORs on the FA maps, and the FA value of each region was measured. FA values of the bilateral anterior and posterior ORs were significantly lower in patients with glaucoma (anterior right, P = 0.0002; anterior left, P = 0.00028; posterior right, P = 0.0004; and posterior left, P = 0.0001) than in the healthy controls. In glaucoma patients, significant correlations were observed between the FA values and the average of the total deviation of the contralateral hemifields of both eyes (left hemifield and anterior right OR, correlation coefficient [r] = 0.46 [P = 0.013]; right hemifield and anterior left OR, r = 0.43 [P = 0.021]; left hemifield and posterior right OR, r = 0.54 [P = 0.0027]; and right hemifield and posterior left OR, r = 0.46 [P = 0.012]). FA values of the entire OR were decreased in glaucoma patients and correlated with the degree of visual field defect.