Eye Problems Astigmatism

Astigmatism is a mild, easily treated, common vision problem that is often accompanied by nearsightedness or farsightedness. It can occur in both children and adults and is usually caused by an irregularly shaped cornea or an irregularly shaped lens.

In an eye with astigmatism, the cornea is shaped oblong, like a football, rather than spherical. Due to this abnormal shape, the light rays tend to focus on two spots within the eye, rather than on one, making items at any distance appear blurry.

Astigmatism of the Eye

Causes of Astigmatism

Normally, astigmatism is hereditary. Most people with astigmatism are born with misshapen corneas. In these cases, astigmatism remains fairly constant throughout a person’s life. It does not worsen or improve over time.

Astigmatism can also be caused by eye injuries in which the cornea is scarred, complications of eye surgery or keratoconus, a progressive disease in which the cornea thins and gradually bulges into a cone shape.

Symptoms of Astigmatism

Symptoms of astigmatism include:

  • blurring of lines (vertical, horizontal or diagonal)
  • distortion in portions of your visual field
  • eyestrain
  • fatigue
  • headaches.

People with only a slight astigmatism may not notice a vision problem or may experience only slightly blurry vision. The blurriness often occurs in one direction more than another (i.e., vertically, horizontally or diagonally).

In addition, people with astigmatism may have a harder time than those with normal vision discerning fine details. If the astigmatism goes uncorrected, it can cause more serious problems including headaches, eye strain and distorted or blurred vision at any distance.

To prevent long-term problems from developing, eye experts recommend that children have an eye exam at six months of age, at age three and before beginning school. After that, assuming the child does not have vision difficulties, he should have an exam every two years thereafter. Experts recommend that adults have an exam every one to three years, depending on risk factors, age and physical condition.

Astigmatism can be detected during a routine eye exam using these tools: keratometer, keratoscope and videokeratoscope. While the keratometer measures reflected light from the surface of your cornea, the keratoscope and videokeratoscope detect and quantify the curvature of the cornea to identify the presence of astigmatism.

Astigmatism Correction

Regardless of its cause, astigmatism can be corrected in several ways. If the astigmatism is slight and nearsightedness or farsightedness is also present, a patient can wear eyeglasses or contacts to correct both conditions. In very mild cases where other vision problems are not present, the astigmatism does not need to be addressed.

In more severe cases, however, astigmatism can be corrected through refractive surgery. With refractive surgery, cuts are made to the cornea to change the cornea’s curvature.

Years ago patients with astigmatism could only wear hard contact lenses, or rigid gas-permeable lenses, to correct their vision. This is no longer true. Now, astigmatism can be corrected with toric contact lenses, which come in both hard and soft varieties. A patient’s preference will depend which type of lens provides clearer vision, as well as which lens feels more comfortable. Like other contact lenses, toric lenses come in many styles. Patients can choose extended wear or disposable, hard or soft and multifocal lenses. Patients can even wear colored contacts for astigmatism.