Visual Pathway

The Optic nerve exits the eye just off center near the fovea. The area where the optic nerve exits is referred to as the blind spot due to the lack of the receptors in this area. The two optic nerves come together at the optic chiasm located just under the hypothalamus in the brain. It is here that a crucial part of vision and perception must happen. Information from each eye must be processed in both halves of the brain. This cross-over of information, i.e. information from the right eye crosses over to the left side and visa versa, happens at the optic chiasm. Information from the medial halves of each eye crosses over to be processed on the opposite half of the brain. Information enters the optic chiasm via the optic nerve. Information leaves the chiasm via the optic tract.

The optic tract consists of two distinct tracts, one headed for processing on the righ side of the brain. The other is headed for processing on the left side of the brain. The right tract contains information from the right eyes lateral half and the left eyes medial half. The tract on the left side contains information from the left eyes lateral half and the right sides medial half.

A reorganized optic tract leaves the optic chiasm and passes onto the lateral geniculate nucleus. Once the information is successfully relayed to the lateral geniculate nuclei it is separated, organized, and relayed to different areas of the visual cortex. The different zones of the visual cortex process the different aspects of vision. It is here that information, taken from both visual fields, is processed and an image is perceived.

(see Visual Fields for more information)