Astigmatism is an eye condition causing refractive error



What Is Astigmatism?

Astigmatism is a refractive error, meaning it is not an eye disease or eye health problem, but rather it's simply a problem with how the eye focuses light. In an eye with astigmatism, light fails to come to a single focus on the retina to produce clear vision. Instead, multiple focus points occur, either in front of the retina or behind it, or both. Astigmatism is very common, with more than 25% of the population having in one, or both eyes.

The Cause Of Astigmatism

Astigmatism usually is caused by an irregularly shaped cornea. Instead of the cornea having a symmetrically round shape (like a baseball), it is shaped more like a football, with one meridian being significantly more curved than the meridian perpendicular to it.

Types Of Astigmatism

There are three primary types of astigmatism:
  • Myopic astigmatism. One or both principal meridians of the eye are nearsighted.
  • Hyperopic astigmatism. One or both principal meridians are farsighted.
  • Mixed astigmatism. One principal meridian is nearsighted, and the other is farsighted.

Correcting Astigmatism

Astigmatism, like nearsightedness and farsightedness, usually can be corrected with eyeglasses, contact lenses or refractive surgery. In addition to the spherical lens power used to correct nearsightedness or farsightedness, astigmatism requires an additional cylinder lens power to correct the difference between the powers of the two principal meridians of the eye.

Symptoms Of Astigmatism

Astigmatism is a common refractive error that occurs when the cornea or lens of the eye has an irregular shape, leading to blurred or distorted vision. The symptoms of astigmatism can vary in severity and may include:
  • Blurred Vision. The primary symptom of astigmatism is blurred vision at all distances. Objects can appear fuzzy, both up close and far away.
  • Distorted or Warped Vision. Astigmatism can cause objects to appear stretched, slanted, or distorted, particularly when looking at fine details or lines.
  • Eyestrain. Individuals with astigmatism often experience eyestrain, especially after prolonged periods of reading, using digital screens, or performing tasks that require focused vision.
  • Headaches. Persistent headaches, especially around the eyes, can occur due to the extra effort required to focus with astigmatism.
  • Difficulty with Night Vision. Astigmatism can lead to difficulties with night vision, causing glare, halos, or starbursts around light sources.
  • Squinting. People with astigmatism may unconsciously squint to try to improve their vision, as squinting temporarily changes the way light enters the eye.
  • Eye Discomfort. Astigmatism can cause general eye discomfort, dryness, and irritation due to the strain placed on the eye muscles.
  • Difficulty Seeing Clearly at Various Distances. Unlike some other refractive errors, astigmatism can affect vision at all distances, making both near and far objects appear unclear.

It's important to note that these symptoms can be similar to those of other vision problems or eye conditions. If you're experiencing any of these symptoms, a comprehensive eye exam by an optometrist is recommended to determine if astigmatism or another vision issue is the cause. Early detection and appropriate corrective measures can significantly improve your visual clarity and overall eye health.

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