ANATOMY OF THE EYE
Your eye is an extremely sophisticated and complex organ. It is not unlike the optical system of a camera. Light enters the eye through the cornea, a powerful focusing surface which is responsible for about 70% of your prescription. After the cornea it goes through a clear liquid which is known as the aqueous fluid, and then passes through a small aperture called the pupil. The iris is a colored ring of tissue which contracts and relaxes to regulate the size of the pupil (the opening formed by the iris) and thereby adjusting the amount of light that gets through. Light rays on entering the pupil are focused through the lens and proceed through a clear jelly-like substance in the center of the eye called the vitreous, which gives the eye its form and shape. The light rays fall on the retina as an upside down image. The visual receptors on the retina convert the image to electric impulses which are sent along the optic nerve to the brain, where it is interpreted as an upright image.
