Eye Problems: Astigmatism


About one in three people have an eye condition called astigmatism. In most cases it is not serious and can be corrected. The name astigmatism comes from two Greek roots, a meaning not, and stigma meaning focus. The primary symptom of astigmatism is the lack of ability to focus on near or far objects.

Most everyone has a degree of astigmatism. But most of us can adjust to it and need no correction. Those with more severe astigmatism will need additional help.

The cornea of the eye – that clear disk on the front of the eyeball – is supposed to be spherical. If it is, it allows parallel beams of light to pass through and focus on one spot on the retina in back of the eye, where it is turned into electrical impulses and sent to the brain. A person with astigmatism has an irregularly-shaped cornea and thus, light focuses on more than one place on the retina. This causes the astigmatism symptom of blurry vision. The central three millimeters of the cornea is the area most crucial for proper vision. Astigmatism is measured in diopters.┬áMore than one diopter usually requires correction of some sort.

Astigmatism Causes

Many causes of astigmatism are known. Often it is inherited from one or both parents. It can also be caused by an injury to the eye, the result of surgery, eye infections, work that requires viewing close objects for long periods of time, and even poor posture. Keratonconus is a rare cause of astigmatism in which the cornea gradually loses its spherical shape over time. If this is severe, the patient may require a cornea transplant. Astigmatism can also be caused by irregularities in the lens that is situated just behind the pupil. This is often the result of high blood sugar levels and thus is more common with diabetics.

Astigmatism Symptoms

If you suffer from the astigmatism symptoms of headaches, eyestrain, blurred vision, or fatigue, it would be good to get an eye exam from an optometrist or ophthalmologist. They are trained to detect astigmatism or other vision problems and to know how to correct them.

Astigmatism Treatments

Astigmatism is treated in three ways. First, it can be corrected by eyeglasses, specifically toric lenses. These have a greater refracting ability in one direction than in the other. They can be designed to correct vision problems for those who also have myopia (nearsighted vision) or hyperopia (farsighted vision).

Contacts are also available to correct problems with astigmatism. However, these contacts have one thing different in their design from those correcting just myopia or hyperopia. Because the cornea of a person with astigmatism bends the light more one direction than another, the contact correcting it cannot be free to spin about as contacts normally do. Therefore, the contact lens used to correct astigmatism is weighted so that it is always upright. Also, more severe cases of astigmatism require hard contact lenses.

A third way that astigmatism is corrected is with Lasik laser surgery. In this procedure, a window in the cornea is cut open and then, with cool laser light, the cornea is reshaped to correct the irregularity. If successful, a person will no longer need glasses to correct the astigmatism problems.

If you have experienced any of the symptoms of astigmatism, please have your eyes checked soon. Don’t wait until it gets worse. And if they’re already pretty bad, consider the option of Lasik.