Astigmatism is a common visual defect and occurs in almost everybody to some degree. It can be corrected by surgery, contact lenses and eye glasses. Astigmatism is caused due to an irregular shaped cornea or the curvature of the lens in the eye. These do not allow the light from focusing on the retina leading to blurred vision. Astigmatism is not a disease; it just means that there is a variation in the shape of your cornea.