BASIC VISUAL PATHWAYS
A. The pathway:
Vision is generated by photoreceptors in the retina, a layer of cells at the back of the eye. The information leaves the eye by way of the optic nerve, and there is a partial crossing of axons at the optic chiasm. After the chiasm, the axons are called the optic tract. The optic tract wraps around the midbrain to get to the lateral geniculate nucleus (LGN), where all the axons must synapse. From there, the LGN axons fan out through the deep white matter of the brain as the optic radiations, which will ultimately travel to primary visual cortex, at the back of the brain.
B. Visual fields:
Information about the world enters both eyes with a great deal of overlap. Try closing one eye, and you will find that your range of vision in the remaining eye is mainly limited by your nose. The image projected onto your retina can be cut down the middle, with the fovea defining the center. Now you have essentially two halves of the retina, a left half and a right half. Generally, the halves are referred to as a temporal half (next to your temple) and a nasal half (next to your nose).