What is Astigmatism

Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina, resulting in blurred vision. It occurs when the cornea — the clear, dome-shaped surface that covers the front of the eye — or lens inside the eye is curved more steeply in one direction than in another. This irregular curve prevents light from focusing properly on the retina, the sensitive layer of tissue at the back of your eye that converts light into electrical impulses and sends them to your brain. As a result, astigmatism causes blurred vision.

Most people have some degree of astigmatism. In fact, it’s quite common for babies to be born with this condition. Usually, astigmatism is mild and doesn’t require treatment. But sometimes it can be severe enough to affect your ability to see clearly. If you have moderate or severe astigmatism, you may need eyeglasses or contact lenses to correct your vision. In some cases, surgery may be needed.

Astigmatism isn’t related to aging and usually develops early in life. It often runs in families, so you may be more likely to develop this condition if someone else in your family has it.

There are two types of astigmatism: regular (simple) and irregular (complex). Regular astigmatism is the more common type. It occurs when your cornea or lens is curved more in one direction than in another, like an egg. This type of astigmatism can be corrected with eyeglasses or contact lenses.

Irregular astigmatism is less common and occurs when your cornea or lens isn’t curved evenly. This type of astigmatism is usually caused by an injury to your eye or by certain diseases, such as keratoconus. Irregular astigmatism can’t be corrected as easily as regular astigmatism and may require surgery.

What a person with Astigmatism sees: