ASTIGMATISM

Astigmatism results in the blurring of all images, whether they are near or far. This usually occurs when the cornea is shaped like a football- with a steeper curve in one direction and flatter curve in the other-rather than round like a basketball. This uneven shape causes light rays entering the eye to focus on more than one point, rather than only the retina as they should.

When you have astigmatism, images focus in more than one place in the eye, because your eye is shaped unevenly.

Astigmatism is very common, affecting about one in four people, and is usually present at birth. If you are nearsighted or farsighted, there’s a good chance that you have a touch of astigmatism, too. A small degree of this refractive error is considered normal and does not require correction.

In mixed astigmatism, the symptoms of nearsightedness and farsightedness occur simultaneously. This combination of vision problems results in the overall inability to see images clearly.

When an eye doctor examines your eyes, he or she has a quantitative way of measuring your vision. These numbers describe your vision problems, their severity, and your prescription for vision correction. Because most people have some astigmatism, the typical prescription notation includes numbers indicating both the degree and direction of the error.

Read more:
Nearsightedness
Farsightedness
Astigmatism
Presbyopia