The optic nerve (cranial nerve II) provides for vision.  Each of the two optic nerves leave the orbit through the optic foramen and unites with the other optic nerve at the optic chiasm.  In the chiasm, some of the nerve fibers cross to the other side.  The optic tract continues and sends signals to the lateral geniculate body, then through the optic radiations to the calcarine cortex of the occipital lobe (where vision is perceived).