What is astigmatism?

Astigmatism is distorted vision caused by an irregular curvature of the front surface of the eye (the cornea). As a result of astigmatism, some images are more in focus in one direction than in another. A person with astigmatism might not see vertical lines clearly. Horizontal lines may be fuzzy to another person with astigmatism, while a third may have trouble seeing diagonal lines.

A little astigmatism is common and may not cause a vision problem. More astigmatism may cause significant blurring and eye fatigue. It can be especially troublesome when one eye has much more astigmatism than the other. This makes it hard to use both eyes together.

How does it occur?

Some people have had astigmatism since birth. Other people develop astigmatism as they get older when the cornea, like skin and other tissues, loses its flexibility. It is also very common to develop astigmatism as part of the healing process after cataract or cornea surgery.

What are the symptoms?

The symptoms of astigmatism are blurred horizontal images, or blurred vertical images. Diagonal images may be blurred as well.

How is it diagnosed?

To diagnose astigmatism, an eye doctor will examine and test your eyes. The sharpness of your vision may be checked by testing your ability to read letters from a chart. Your ability to correctly read letters of different sizes will determine whether your eyesight needs correction. Different lenses may be used to see if your vision can be improved.

Your doctor may also check your eye muscles. He or she may examine your eyes with special instruments to see if you have any eye diseases.

How is it treated?

In minor cases of astigmatism, you will not usually need glasses. For more advanced cases, glasses or contact lenses are normally prescribed to correct the irregular curve of the cornea. For severe cases surgery may be necessary (refractive surgery or corneal transplant).

How can I take care of myself?

Regular eye checkups every 2 or 3 years are advisable (every 2 years is suggested if you are over 40).

Contact your doctor if you experience a noticeable change in your vision, particularly if it gets worse.

Protect your eyes against unnecessary risk of injury in your work and recreation by wearing special glasses or goggles where hazards exist.

Can I help prevent astigmatism?

Because there is no known cause for astigmatism, there is nothing you can do to prevent it.