Eye Anatomy

The eye has been called the most complex organ in our body. It's amazing that something so small can have so many working parts. But when you consider how difficult the task of providing vision really is, perhaps it's no wonder after all.

(Click on the words in the eye anatomy illustration below for their definitions.)

The eye is like a camera. Light comes in through the cornea, a clear cover that is like the glass of a camera's aperture. The amount of light coming in is controlled by the pupil, an opening that opens and closes a little like a camera shutter. The light focuses on the retina, a series of light-sensitive cells lining the back of the eye. The retina acts like camera film, reacting to the incoming light and sending a record of it via the optic nerve to the brain.

For more detailed information, please read the article on "Refraction and Refractive Errors: How the Eye Sees."
 

Other parts of the eye support the main activity of sight: Some carry fluids (such as tears and blood) to lubricate or nourish the eye. Others are muscles that allow the eye to move. Some parts protect the eye from injury (such as the lids and the epithelium of the cornea). And some are messengers, sending sensory information to the brain (such as the pain-sensing nerves in the cornea and the optic nerve behind the retina).