Medical Dictionary Search here

Astigmatism



Astigmatism is a refractive error of the eye that causes the visual image in one plane to focus at a different distance from that of the plane at right angles. This most often results from too great a curvature of the cornea in one plane of the eye.
Astigmatism is the most common refractive problem responsible for blurry vision. You may also hear astimatism called a refractive error.Most of the eyeball's focusing power occurs along the front surface of the eye, involving the tear film and cornea (the clear 'window' along the front of the eyeball). The ideal cornea has a round surface. Anything other than round contributes to abnormal corneal curvature -- this is astigmatism. Here's a good way to demonstrate the effects of astigmatism. Look at your reflection in the curved surface of a round soup spoon and compare it with your reflection in an oval teaspoon.The cornea is the transparent window over the colored part of the eye. It bends (refracts) light rays and helps focus the light onto the retina in the back of the eye so people can see. When the cornea is oblong shaped, it causes light rays to focus on two different points on the retina, instead of just one. As a result, people with significant astigmatism may have distorted or blurry vision.

Signs and symptoms of astigmatism may include:
  • Distortion in portions of your visual field
  • Blurred vision
  • Eyestrain
  • Headaches