Astigmatism FAQs

What is astigmatism?

Astigmatism is a vision condition in which light entering the eye can't be equally focused all at once. For example, the short top, horizontal bar of the letter "T" may be clear while the long vertical line may be blurry, or vice versa. Astigmatism often occurs with other refractive errors like nearsightedness and farsightedness. As a result, vision can be blurred at all distances if astigmatism is not corrected.

Astigmatism usually does not result because of disease, rather, it is a common vision condition. Most people who are nearsighted or farsighted also have some amount of astigmatism.

Why does astigmatism occur?

Typically, astigmatism occurs when the front of your eye (the cornea) is curved differently from top-to-bottom compared to side-to-side, much like the shape of a football or rugby ball is different from the shape of a basketball. The causes of this irregular shape vary. It can be hereditary, or it may result from pressure of the eyelids on the cornea, trauma and scarring of the cornea, or the vision disorder keratoconus.

What are signs/symptoms of astigmatism?

People with significant amounts of astigmatism will usually have blurred or distorted vision. For example, some lines on a clock dial or wagon wheel can appear clear while others look blurred. People with mild astigmatism may experience headaches, eye strain, fatigue or blurred vision at only certain distances.

How is astigmatism diagnosed?

A comprehensive eye examination by your doctor of optometry will include testing for astigmatism.

How is astigmatism treated?

Astigmatism can generally be corrected with properly prescribed and fitted eyeglasses or contact lenses. For patients who qualify for refractive surgery, surgery such as LASIK or PRK can permanently alter the shape of the cornea. A procedure called orthokeratology uses a series of rigid contact lenses to temporarily alter the shape of the cornea and provide improved vision for one to two days at a time. Your doctor of optometry can help you decide what treatment is right for you.

How common is astigmatism?

Most people have some amount of astigmatism. However, usually only individuals with moderate to high amounts need correction.

How will astigmatism affect me?

You may have to adjust to wearing eyeglasses or contact lenses if you do not wear them now. Other than that, astigmatism probably will not significantly affect your lifestyle. Astigmatism may change slowly. Regular visits to your doctor of optometry can help you maintain proper vision.


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