Nonuniform Pressure Generation in the Optic Chiasm May Explain Bitemporal Hemianopsia

During deformation of the optic chiasm from below by a radially expanding mass analogous to a pituitary tumor, the central aspect of the optic chiasm consistently manifests a higher pressure than the temporal aspect. It is hypothesized that the peculiar geometry of the optic chiasm renders the crossing nasal fibers more prone to a deformation stress exerted from below. Nonuniform pressure generation between the central and temporal aspects of the chiasm results in a greater effective stress on the crossing fibers of the chiasm and may be responsible for the clinical phenomenon of bitemporal hemianopsia.