The eye has three major parts: the globe, the orbit, and the adnexal structures. The globe (eyeball) is filled with a jelly-like material called vitreous. The uvea and the retina are two important parts of the globe. The uvea consists of: the iris (the colored or pigmented part surrounds the pupil, the opening that controls the amount of light that enters the eyeball) the choroid (a thin, pigmented layer lining the eyeball that nourishes the retina and the front of the eye with blood) the ciliary body (contains the muscles inside the eye that change the shape of the lens so that the eye can focus on near or distant objects and cells that produce aqueous humor, fluid in the eye) The retina is like the film in a camera. It is found in the back of the eyeball and contains specialized nerve cells that are sensitive to light. These light-sensing cells are connected to the brain by the optic nerve. The pattern of light (image) appearing on the retina is sent from the retina to an area of the brain called the visual cortex, allowing us to see. Cancers that affect the eyeball are called intraocular (within the eye) cancers. The second part of the eye, called the orbit, consists of the tissues surrounding the eyeball. These tissues include muscles that make the globe move in different directions and the nerves attached to the eye. Cancers of these tissues are called orbital cancers. Finally, there are adnexal (or accessory) structures such as the eyelids and tear glands. Cancers that develop in these tissues are called adnexal cancers.