astigmatism

Astigmatism is an irregular curvature of the lens or the cornea of the eye. In simple terms, it’s a problem with how the eye focuses light. It is the most common vision problem and may accompany nearsightedness or farsightedness.

Astigmatism is a lifelong condition. It may worsen slowly over time but usually, it remains stable throughout life.

Causes?

Astigmatism is usually it is caused by an irregularly shaped cornea. However, sometimes it is the result of an irregularly shaped lens.

Astigmatism caused by an irregularly shaped cornea is called corneal astigmatism. Astigmatism caused by an irregularly shaped lens, is called lenticular astigmatism. Usually astigmatism is hereditary. If one or both of your parents have it, you will probably develop it.

Signs and symptoms

Some of the most common symptoms are:

  • blurred vision
  • distorted vision
  • headaches
  • eye strain
  • squinting

The symptoms are most noticeable after reading or other prolonged visual tasks.

Kinds of astigmatism

There are three kinds of astigmatism: Myopic, hyperopic, and mixed.

  • Myopic astigmatism
    • One or both principal meridians of the eye are nearsighted.
  • Hyperopic astigmatism
    • One or both principal meridians are farsighted.
  • Mixed astigmatism
    • One prinicipal meridian is nearsighted, and the other is farsighted.

*When thinking about meridians, picture them as circles passing through the front and back poles of the eyeball.

Astigmatisms can also be classified as irregular. Irregular astigmatisms are most often caused by an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus.

Diagnosis?

Your eye doctor can diagnose astigmatism using a standard eye examination. Your eye doctor will use a test called a retinoscopy to estimate the amount of astigmatism. Retinoscopy involves you shining a light into your eye while manually introducing a series of lenses between the light and your eye.

Treatments

Astigmatism can usually be corrected with eyeglasses, contact lenses or LASIK surgery.

Can you have LASIK with a stigmatism?

Yes, in most cases (lower than 3.0 diopters (D))  LASIK can fully correct astigmatism, and the effect is permanent. In instances higher than 3.0 diopters (D), followup surgery may be necessary.

Can astigmatism be prevented?

No. Astigmatism is hereditary and is present at birth.