"Astigmatism is a condition in which the cornea, the transparent layer that covers the front part of the eyeball, is not symmetrical. The cornea bends or refracts light rays to focus the light onto the retina in the back of the eye, but when it doesn't cover the eyeball evenly, the light rays are not focused on a single point. The result can be blurry vision. However, small amounts of astigmatism usually don't lead to vision problems, as blinking helps maintain the cornea's symmetrical curve. Infants can be born with astigmatism, or it can be caused by heavy eyelids, blunt trauma to the eyeball, scarring of the cornea from lacerations, and infection. Astigmatism is measured in diopters. A measurement of 1 diopter often requires correction with eyeglasses or contact lenses. Follow the links below to find WebMD's comprehensive coverage of astigmatism, how it develops, what it looks like, how to treat it, and much more."