The bundles of nerve fibers then come together again just before they reach the back part of the brain, where vision is sensed and interpreted. The eyeball itself is divided into two segments, each filled with fluid. These fluids help the eyeball maintain its shape. The anterior segment itself is divided into two chambers. Normally, the aqueous humor is produced in the posterior chamber, passes through the pupil into the anterior chamber, and then drains out of the eyeball through outflow channels at the edge of the iris.
Several muscles working together move the eyes.
Each muscle is stimulated by a specific cranial nerve. The bony orbit that protects the eye also contains many other nerves. As mentioned, the optic nerve exits through the back of the eye and carries nerve impulses created in the retina to the brain. The lacrimal nerve stimulates the tear glands to produce tears. Other nerves transmit sensation to other parts of the eye and stimulate the muscles of the orbit.