What is Astigmatism?

Normal Eye Astigmatism

Astigmatism occurs when the cornea is shaped more like an oblong football than a spherical baseball, which is the normal shape. In most astigmatic eyes, the oblong or oval shape causes light rays to focus on two points in the back of your eye, rather than on just one. This is because, like a football, an astigmatic cornea has a steeper curve and a flatter one. It may accompany with near-sightedness or far-sightedness. Usually astigmatism is hereditary: many people are born with an oblong cornea, and the resulting vision problem may get worse over time. But astigmatism may also result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery, or from keratoconus, a disease that causes a gradual thinning of the cornea.

Signs and symptoms

If you have only a small amount of astigmatism, you may not notice it or have just slightly blurred vision. But sometimes uncorrected astigmatism can give you headaches or eyestrain, and distort or blur your vision at all distances.

Treatment

Astigmatism can be compensated for satisfactorily with eyeglasses or contact lenses. Depending on the type and severity of your astigmatism, you may also be able to have it corrected with refractive surgery.