Final answer:
The optic chiasm is where the optic nerves from both eyes intersect, allowing for the crossing of fibers carrying information from the right and left visual fields to the opposite hemispheres of the brain. Damage to this area can affect visual perception.
Step-by-step explanation:
The optic chiasm is a crucial anatomical feature in the human visual system, where the optic nerves from both eyes intersect. Within this X-shaped structure, located just below the cerebral cortex at the front of the brain, the nerve fibers from the medial retinas cross, or decussate, to the opposite side. This crossing allows visual information from the right visual field to be sent to the left hemisphere of the brain and vice versa for the left visual field. This decussation ensures that the visual cortex receives input from both eyes for the corresponding half of the visual field. Damage to the optic chiasm, such as from a pituitary tumor, can lead to deficits in visual field perception, such as loss of peripheral vision. After passing through the optic chiasm, the nerve fibers continue as the optic tract, which has major targets in the diencephalon and midbrain, including the lateral geniculate nucleus of the thalamus that projects to the visual cortex of the occipital lobe.