Astigmatism is a common eye condition that is corrected by eyeglasses, contact lenses, or surgery. It is caused by an eye that is not completely round. The front surface of the eye (cornea) of a person with astigmatism is not curved properly. When light rays enter the eye that has astigmatism, they do not focus correctly on the retina. This misdirection of light rays, results in a blurred image.