Understanding the Eye

The Normal Eye

The normal eye without a refractive error is a perfect sphere, like a tennis ball. Light enters the eye through the clear cornea (the "windowpane" of the eye) and the pupil to form an image on a film in the back of the eye. This film is called the retina.

Nearsighted (myopia)

People who are nearsighted have a cornea that is too steep, or the globe of the eye is too long. Light is focused on the front of the retina, making images in the distance seem blurry.

Farsightedness (hyperopia)

Farsightedness occurs when the cornea is too flat, or the globe of the eye is too short, and light comes to focus at a point somewhere behind the retina. Both distant and near images are blurry.

Astigmatism

Astigmatism is a condition where the shape of the cornea is oval like a football, rather than spherical, like a tennis ball. Light entering the eye is focused at multiple points on the retina, causing an image to have a "ghosting" effect. Both nearsighted and farsighted people can have astigmatism.

Presbyopia

Presbyopia is an age-related condition in which the natural crystalline lens that helps focus light rays becomes rigid. Because of this natural aging process, most normal sighted or farsighted people and many nearsighted people need to use reading glasses to see close objects. If you are over forty, you may have to continue to wear reading glasses after a refractive procedure. Be sure to discuss this with your doctor before you decide if Refractive Vision Correction is right for you. After the refractive procedure, you may be free of glasses for distance, but not free of reading glasses in most instances.