 The
cornea and lens of the eye together work to focus incoming
light like a camera lens to form an image on the retina located
in the back of the eye.
The cornea is where the light first enters the front of the eye. It provides about two thirds of the eye's focusing power and the lens inside the eye provides the other third.
 Some eyes focus or refract the incoming light too much, or the eye is longer than normal, so the images of distant objects are formed in front of the retina, and the image on the retina is blurred. This condition is called nearsightedness or myopia. Farsightedness or hyperopia is the opposite condition where the eye is deficient in focusing power resulting in images being formed behind the retina. Patients with hyperopia have difficulty seeing up close but can also have difficulty seeing distances depending on the extent of the problem. Hyperopic eyes are too short. Astigmatism occurs when either the cornea and/or the lens is cylindrical or football shaped instead of spherical in shape. This creates a frosting of the image with resulting blurred and ghosting vision.
Learn more about nearsightedness, click here.
|
