What is Astigmatism?


Diagnosed through an eye exam, astigmatism is a fairly common condition typically corrected with contact lenses, eyeglasses, or surgery. Astigmatism occurs when the cornea or lens of one or both eyes isn’t entirely rounded. The extent of vision problems experienced will depend on the degree of the imperfection.

Types of Astigmatism

Astigmatism falls into one of two broad categories. The more common of the two, corneal astigmatism, refers to a distorted cornea. A lenticular astigmatism is caused by a distorted lens. Specific types of astigmatism include:

What are the Symptoms of Astigmatism?

Astigmatism is often present at birth, although the condition can improve or become worse over time. If left untreated, astigmatism can lead to various degrees of eyestrain.

Symptoms include:

  • Headaches
  • Fatigue
  • Blurred vision
  • Difficulty focusing at certain distances

Astigmatism Causes

An irregular curvature of the lens in the eye or the cornea causes astigmatism. Light rays cannot refract in a proper manner if the lens or cornea is not evenly curved and smooth, and this is is known as a refractive error. Distorted or blurred vision occurs with both near and far distances for those with astigmatism.

This diagnosis is common and most people that have the condition are born with it. It is not known why exactly astigmatism causes the corneal shape to be different for different people. Developing astigmatism is hereditary.

Eye injury, surgery, or disease can cause astigmatism to develop. Astigmatism cannot be developed from sitting close to the television or from reading in bad light.

How is Astigmatism Treated?

What’s considered “normal astigmatism,” referring to a slight or mild curvature of the lens or cornea, is often corrected with prescription eyeglasses or contact lenses. If astigmatism is mild enough, corrective lenses may not be required. Corrective lenses are usually necessary for moderate to high astigmatism.

Irregular Astigmatism

Considered rare, irregular astigmatism is characterized by abnormalities of the cornea. Treatment may include rigid gas permeable contact lenses. Corneal surgery may be recommended if the irregularity is severe.

Refractive Surgery

Commonly referred to as “laser eye surgery,” refractive surgery is a permanent corrective procedure that changes the shape of the cornea or lens. Ideal candidates must have otherwise healthy, disease-free eyes.

Even though astigmatism affects millions of people, there is no definitive cause. While refractive surgery is an appealing solution to correct the condition, it’s not for everyone. An eye doctor will determine what corrective options are available for a patient to consider.

Astigmatism Prevention

There is not a way to prevent astigmatism as it is present from birth and hereditary. It is however still important to keep the eyes healthy by following a good diet. Eye exercises may also be beneficial in keeping the eyes from becoming too dry for those who work in front of the computer.

There are ways to correct the condition, however. Specific contact lenses, glasses, or surgery are all ways to counteract astigmatism. Glasses are a non-invasive and reliable way of correcting it, whilst hard contact lenses are ideal for those with the condition, as soft lenses are not effective in counteracting severe cases.

Surgery is an option to permanently solve astigmatism, and it is especially helpful for those with exceptionally dry eyes or conditions that do not allow them to wear corrective lenses. Laser in situ keratomileusis, or LASIK, is the most reliable surgery available that can be used to correct astigmatism. A small flap of tissue is created in LASIK, which comes from a tiny incision on the outward portion of the eye, and is then lifted up. A cooled laser beam then corrects the uneven curvature that is causing the astigmatism. After the laser corrects the surface, the flap is returned, and recovery is typically painless and quick.

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Last Reviewed:
September 12, 2016
Last Updated:
June 06, 2018
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