Quantitative analysis of the displacement of the anterior visual pathway by pituitary lesions and the associated visual field loss

PURPOSE. To evaluate quantitatively the relationship between the displacement of anterior visual pathway structures by pituitary tumors and visual field damage with the goal of improving diagnosis and management. METHODS. Subjects had pituitary macroadenomas and both magnetic resonance imaging (MRI) and static perimetry. Neuroradiologists measured the displacement of anterior visual pathway structures and right-left tumor asymmetry. To quantify the degree and laterality of visual field loss, we used algorithms from the neurologic hemifield test to analyze each right-left pair of visual fields with respect to temporal asymmetry, the proportion of loss that was temporal, total asymmetry, and total damage. We compared these metrics with the displacement of anterior visual pathway structures and tumor asymmetry. RESULTS. Of 114 subjects, 64 (56%) were male and the median age was 57 years (range, 14-88). The summation of vision loss in both eyes and the proportion of temporal loss were statistically significantly related to the maximum displacement of the anterior visual pathway (both P < 0.001 for fit of linear regression). The relationship between the asymmetry of visual field loss in the two eyes and the subjective assignment of tumor asymmetry on MRI did not achieve statistical significance (P = 0.06 by analysis of variance). CONCLUSIONS. Displacement of the anterior visual pathway by pituitary tumors is associated with both the total amount of visual field loss and the proportion of temporal visual field loss. Although there was right-left asymmetry of vision loss in some subjects, it was not related to the subjective assessment of tumor asymmetry.