Astigmatism means that the cornea, or window, of the eye is not round or spherical. A cornea without astigmatism is round or spherical (like a basketball). A cornea with astigmatism is shaped more like a football, with two different curvatures, one steeper than the other. The flatter curve is weaker and therefore doesn't focus the image as much as the steeper, more powerful curve.

The flatter curve is weaker and therefore doesn't focus the image as much as the steeper, more powerful curve. The result is an eye with two different points of focus, giving you blurry vision. The image may not only be blurred, but may be seen as a doubled or distorted image.

Astigmatism is a very common vision condition. Most people have some degree of astigmatism. Slight amounts of astigmatism usually don't affect vision and don't require treatment. However, larger amounts cause distorted or blurred vision, eye discomfort and headaches.

Astigmatism frequently occurs with other vision conditions like nearsightedness (myopia) and farsightedness (hyperopia). Together these vision conditions are referred to as refractive errors because they affect how the eyes bend or "refract" light.

The specific cause of astigmatism is unknown. It can be hereditary and is usually present from birth. It can change as a child grows and may decrease or worsen over time.

A comprehensive optometric examination will include testing for astigmatism. Depending on the amount present, your Optometrist can provide eyeglasses or contact lenses that correct the astigmatism by altering the way light enters your eyes.