Astigmatism

Astigmatism is a condition where vision is disordered (blurred, unfocused, fuzzy) because the cornea (the front surface of the eye) or lens, which is located behind the cornea, has an abnormal or irregular curve (misshaped). Astigmatism can occur in children as well as adults. Astigmatism is fairly common and not contagious. There are two common types of astigmatism: corneal astigmatism and lenticular astigmatism. Corneal astigmatism is when the cornea is misshaped. ; Lenticular astigmatism is when the lens is misshaped.

  • Causes

    The precise cause of astigmatism is unknown. It is often present at birth and may coexist with nearsightedness or farsightedness. Sometimes it may occur after an injury or eye surgery.

  • Definition

    Astigmatism is a condition where vision is disordered (blurred, unfocused, fuzzy) because the cornea (the front surface of the eye) or lens, which is located behind the cornea, has an abnormal or irregular curve (misshaped). Astigmatism can occur in children as well as adults. Astigmatism is fairly common and not contagious.


    There are two common types of astigmatism:
    corneal astigmatism
    and
    lenticular astigmatism.

    • Corneal astigmatism is when the cornea is misshaped.
    • Lenticular astigmatism is when the lens is misshaped.

    Normal Anatomy of the Eye
    IMAGE
    Copyright © Nucleus Medical Media, Inc.

  • Diagnosis


    Your doctor will ask about your symptoms and medical history, and perform a physical exam. You may also be referred to a doctor who specializes in the medical and surgical treatment of eye disorders and vision measurements (ophthalmologists) or a trained and licensed professional who can diagnosis vision and eye disease and prescribe corrective lenses (optometrist). Tests may include the following:

    • Visual acuity assessment test (VAT)—this test is used to measure how well you can distinguish different size letters or symbols (very large to very small) at a specific distance
    • Refractor test—this test uses a refractor, a special instrument that has interchangeable lenses of different strengths to measure how well you see objects at various distances. The ophthalmologist or optometrist will ask you to look through the lens and read a chart that is several feet away. The ophthalmologist or optometrist will adjust the strength of the lens based on your responses.
    • Keratoscope—a device used to detect and measure the presence of corneal surface curvature

  • Prevention

    There are no known preventative measures that will reduce your chances of getting astigmatism. However, routinely getting a comprehensive vision exam will reduce your chances of astigmatism going undetected (unidentified) and untreated.

  • Risk Factors

    A risk factor is something that increases your chance of getting a disease or condition.


    The following factors increase your chances of developing astigmatism. If you have any of these risk factors, tell your doctor:

    • Heredity—a family history of astigmatism, eye disease, or disorders such as
      keratoconus

    • Eye surgery—certain types of eye surgery, such as
      cataract
      (lens of the eyes are cloudy) removal
      (less common with modern techniques)
    • A history of corneal scarring or thinning

    • A history of excessive
      nearsightedness
      (a visual defect where distant objects appear blurred) or
      farsightedness
      (a visual defect where distant objects are seen better than objects that are close)

  • Symptoms


    The symptoms for astigmatism vary from person-to-person. Some people might be asymptomatic (showing no signs of the condition) while others are symptomatic (showing signs of the condition). If you experience any of these symptoms, do not assume it is due to astigmatism. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician.

    • Dizziness
    • Headaches
    • Blurred (objects appear fuzzy) or distorted (objects appear twisted or out of focus) vision
    • Excessive squinting or closing of the eyes

  • Treatment

    There are several treatment options for astigmatism. If you suspect you have astigmatism, contact your doctor.Talk with your doctor about the best treatment plan for you. Treatment options include the following: