Basic Anatomy of the Eye (Jared Kellar, O.D.)

The eye has been called the most complex organ in the body. Each cell of your eye is highly specialized and important in providing proper vision.

The eye is often said to be like a camera (although it would be better to say a camera is like your eye). The eye lets light in through the cornea, which is like a camera's opening. The amount of light allowed into the eye is controlled by the iris, which opens and closes a similar to a camera aperture/shutter. The lens and ciliary body of the eye works like an autofocus camera, focusing at distance when looking far away, and changing to focus up close-up when working near, such as during reading. The light focuses on the retina (specifically the macula), which sends the image through the optic nerve to the brain, acting as film would in order to record the light (the photo itself).

Other eye structures support the main activity of sight. Some lubricate or nourish the eye. Others are muscles that allow the eye to move (in all, each eyeball has 9 muscles!). Some protect the eye from injury (eyelidslids and the epithelium of the cornea). And some are messengers, sending sensory information to the brain (pain-sensing nerves in the cornea and the optic nerve behind the retina).