What is Astigmatism?

What is Astigmatism?

What Does Astigmatism Mean?

  • Astigmatism is a very common refractive (focusing) error.
  • It occurs when the front curvature portion of the cornea has an oval shape (like a football) rather than a round shape (like a baseball).
  • The two different curves in such a corneal surface each bend light rays to a separate focus point.
  • Astigmatism correction makes all the rays of light focus at the same distance so that they all fall correctly on the retina.
  • Small degrees of astigmatism do not impact vision significantly, but with medium and larger amounts, distortion and blur occur.

Two Types of Astigmatism  

There actually are two types of astigmatism, both dealing with irregularities at the front of the eye. When the cornea has an irregular shape, this is called corneal astigmatism. A lenticular astigmatism means the shape of the lens is distorted. With either type, both near and far objects appear blurry or distorted.

Astigmatism can occur alone as the sole optical error, or may occur together with either myopia or hyperopia.


Most people probably are born with some degree of astigmatism, perhaps along with other refractive errors. While adults may realize their vision isn't as good as it should be, children with astigmatism may not be aware they have it, and are unlikely to complain about their vision. Uncorrected astigmatism can impact a child's ability to achieve in school and other activities, so it’s crucial they have regular eye exams to detect and treat astigmatism as early as possible. 

Mild to moderate astigmatism can be corrected with eyeglasses or contact lenses. In some cases, LASIK or another type of refractive surgery might be an option to correct vision.

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