optic chiasm

n. The point at which the branches of the optic nerve from each eye meet. The half of the neuronal fibers from the outer side of the retina in each nerve continue on the same side of the brain back toward the lateral geniculate nuclei, superior colliculus, and the optic cortex, while the half from the nasal side of the retina cross over and travel toward the opposite side of the cortex. The fibers cross in such a way that the receptors from the right side of the visual field send impulses to the left side of the brain, and vice versa.