The Eye A Biological Camera

The eye functions much like a camera. Light passes through the cornea and the lens of the eye and is focused on the retina in much the same way that an image is focused on the film of a camera.

The cornea and the lens are transparent and bend light rays in such a way that an image is projected onto the the retina. The iris, the colored part of eye, contains the pupil which controls the amount of light entering the eye in much the same way as the shutter of a camera controls the amount of light entering a camera. The light rays then pass through the vitreous cavity that is filled with a clear gelatinous material and are finally focused on the retina. The image on the retina is then transmitted to the brain through the optic nerve. This is the basic mechanism of vision.

Anatomy Of The Lens

The natural lens of the eye is located behind the colored part of the eye known as the iris. The lens is like a magnifying glass. The lens is transparent and helps to focus light rays onto the retina in the back of the eye.

In younger individuals the lens is flexible and can change shape. This allows the eye to focus at both near and far. As we get older the lens begins to harden and can no longer focus. This process starts to occur at about 40 years of age and is usually complete by age 60. The natural lens of the eye can also develop opacities with clouding of vision. This is called a cataract.