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Visual acuity test
Visual acuity test

Astigmatism
Definition:
Astigmatism is a condition in which the cornea of the eye is asymmetrically curved, causing out-of-focus vision.

Causes, incidence, and risk factors:

The cause of astigmatism is unknown. It is usually present from birth, and often occurs together with nearsightedness or farsightedness. A minor degree of astigmatism is considered normal and does not require correction. Astigmatism is very common.
Symptoms:

Difficulty in seeing fine detail, either close-up or from a distance.
Signs and tests:

Astigmatism is easily diagnosed by a standard ophthalmic exam with refraction test. Special tests are not usually required. Children or others who cannot respond to questions can have their refractive error measured by a test using reflected light called retinoscopy.
Treatment:

Glasses or hard contact lenses will correct astigmatism. Soft contact lenses do not work as well.
Expectations (prognosis):

Vision is usually normal with the correct glasses or contact lenses.
Complications:
  • There are complications associated with contact lenses (including the risk of corneal abrasion), which may develop if contact lenses are used.
  • Unequal astigmatism may cause amblyopia.
Calling your health care provider:

Call for an appointment with the health care provider or ophthalmologist if vision problems worsen or do not improve with glasses or contact lenses.
Prevention:

Review Date: 11/4/2002
Reviewed By: Raymond S. Douglas M.D., Ph.D. Department of Ophthalmology, UCLA Medical Center, Los Angeles, CA. Review provided by VeriMed Healthcare Network.
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