What is Astigmatism?

Astigmatism is the condition that affects the eye’s ability to refract or bend the light that enters it equally in all directions. It is the result of the curving of the light on the single point on the retina, which might be caused by injury, surgery, or an individual’s genes. Consequently, the person has blurred vision and will see irregularly-shaped objects in the surroundings regardless of the distance.

What a Healthy Eye Should Be

A healthy eye is supposed to have one focal point behind the cornea and the lens. However, a person with astigmatism has multiple focal points because of an astigmatic cornea. The lens is curved or shaped like a football, whereas a healthy cornea should have a round shape. This results in an out-of-focus vision. The condition usually occurs with other visual problems such as hyperopia or farsightedness and myopia or nearsightedness.

Who Can Get Astigmatism

According to ophthalmologists, most people have a slight degree of astigmatism, but these do not require treatment because they do not affect the vision. There is no known specific cause of the condition, but individuals with a family history of astigmatism are more likely to get it than others who don’t.

Some people are also susceptible to it when the curvature of the lens changes during adulthood or because of injury or surgery. In rare cases, astigmatism may be a result of keratoconus, or a condition that is characterized by the thinning of the cornea resulting in a cone-shaped curvature.

How Astigmatism is Diagnosed

Symptoms of astigmatism include blurred vision, headaches, eye strain, and squinting. An eye specialist called an ophthalmologist can perform several tests to diagnose visual problems correctly. If you suspect that you have astigmatism, the doctor will need tests that measure how the light focuses on your eyes, such as; refraction, visual acuity, and topography or keratometry.

A phoropter is used to measure the refraction of light in your eyes, while visual acuity is measured by asking you to read a distance chart. Topography on the other hand, will measure the curvature of your cornea using the keratometer.

There are three types of astigmatism that you should be aware of:

  1. Hyperopic astigmatism or farsightedness. Both eyes are hyperopic in different degrees.
  2. Myopic astigmatistm or nearsightedness. Both eyes are myopic in different degrees.
  3. Mixed astigmatism. One is nearsighted and the other is farsighted.

How Astigmatism is Treated

Based on the results of the tests listed above, the doctor will prescribe treatments such as eyeglasses to improve the quality of your vision or contact lenses for people with irregularly-shaped cornea.

Laser and refractive surgery is recommended for reshaping cornea by photorefractive keratectomy or laser in situ keratomileusis. Orthokeratology is recommended if you have moderate astigmatism. In this process, you will be fitted with rigid contact lenses to reshape your cornea.

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