Astigmatism is a condition that causes blurred vision due to the irregular shape of the cornea or the lens inside the eye. The cornea and lens are primarily responsible for properly focusing light entering your eyes allowing you to see things clearly.
The curvature of the cornea and lens causes light entering the eye to be bent in order to focus it precisely on the retina at the back of the eye. In astigmatism, the surface of the cornea or lens has a somewhat different curvature in one direction than another. In the case of the cornea, instead of having a round shape like a basketball, the surface of the cornea is more like a football. As a result, the eye is unable to focus light rays to a single point causing vision to be out of focus at any distance.
Sometimes astigmatism may develop following an eye injury or eye surgery. A comprehensive eye examination will include testing for astigmatism. Depending on the astigmatism, your eye doctor can provide eyeglasses or contact lenses that correct the astigmatism by altering the way light enters your eyes.
For more information on eye conditions, visit American Academy of Ophthalmology EyeSmart.