You can understand the way your eyes work by thinking of a camera. The white part of your eye is called the sclera. In its center is the cornea, the transparent part of the eye that covers the iris or colored part of your eye. The iris operates like a camera shutter by controlling the amount of light that enters the eye.
Located behind the iris is the eye lens. It is suspended by fibers that tighten or loosen to focus the light rays from objects outside the eye onto the retina, located at the back of the eye. The retina is like film in a camera.
The vitreous makes up the main mass of your eye. It fills the space between the lens and the retina, and is filled with a clear, gelatinous fluid. Within the layers of the retina are special cells that perceive light and color. The images received by the retina are conveyed to the brain by the optic nerve, allowing us to see objects.