Definition The three most common reasons people need glasses are far sightedness, near sightedness and astigmatism. Many people think astigmatism is a disease or neurological problem. It is not. It is an abnormality in the optical part of the eye. It produces a blurred image.
What is going on in the body? An individual with astigmatism has an abnormal curve in the optical part of the eye. It is usually the cornea. Sometimes the lens is involved. When light enters the eye it produces a smeared image rather than sharp focus. Poor vision is the result when the eye has the wrong shape.
What are the signs and symptoms of the condition? Symptoms of astigmatism include blurred vision, things looking fatter or taller than they should or a smeared focus.
What are the causes and risks of the condition? Astigmatism usually occurs naturally. It is caused by an abnormal curvature or shape of the cornea or lens. It may also be caused by injury to the cornea or by any other factor that could change the shape of the cornea or lens.
What can be done to prevent the condition? There is no way to prevent astigmatism. The eye develops this way in some people.
How is the condition diagnosed? Diagnosis is usually made by an eyecare professional during the refraction part of an eye examination. It can also be diagnosed using instruments that measure the curve of the cornea. There are instruments now that can make a map of the cornea.
What are the long-term effects of the condition? In order to focus sharply, a person must have the astigmatism corrected. Vision is helped by using glasses or contact lenses that control the light coming into the eye. The glasses or contact lenses direct the light to a point focus on the retina, rather than a smear. If large amounts of astigmatism are not corrected early in life, it is possible to develop refractive amblyopia, or lazy eye. Perfect vision in that eye will never develop, even later in life.
What are the treatments for the condition? Treatment of astigmatism is usually done with glasses. Glasses adjust for the abnormal shape on the front of the eye by focusing light at a point on the retina. This produces sharp vision. Contact lenses can also correct astigmatism. Recently, refractive surgical procedures have become recognised as a possible treatment for astigmatism. Cuts in the cornea or the use of lasers or other surgical techniques on the cornea have been shown to reduce or get rid of astigmatism. There is no known medical treatment for astigmatism such as eye drops or oral medications.
What are the side effects of the treatments? Contact lenses can correct astigmatism. Wearing contact lenses should be supervised by an eyecare professional. For surgical treatment, the possible side effects include those for any surgical procedure. The surgical approach should be carefully discussed with an ophthalmologist (eye specialist), before undergoing the treatment.
What happens after treatment for the condition? Since treatment for astigmatism usually involves glasses or contact lenses, good vision almost always results. There are no long-term complications.
How is the condition monitored? Monitoring of astigmatism is done during routine eye examinations.
Author: William Stevens, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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