How the eye Works

Think of the eye as a camera and you cannot go far wrong. Instead of film at the back of the eye we have the retina. And just as the lens at the front of the camera focuses an image on the film, so the eye's own focusing system of cornea and lens places an image on the retina. Both the lens and the cornea must be clear if good images are to be formed. In order to focus on different objects, the lens actually changes shape as muscles around it relax and contract. Your pupil acts just like the aperture on a camera, becoming bigger and smaller to cope with different lighting conditions. The retina then converts the image you see to electrical signals for your brain to decode.

Other eye structures 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 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).

So you see, the eye is just like a miniature camera - but far more valuable to you!