What Is Astigmatism?

What Is Astigmatism?

It’s a big word, but it simply means your eye isn’t completely round. Almost all of us have it to some degree.

A normal eyeball is shaped like a perfectly round ball. Light comes into it and bends evenly, which gives you a clear view. But if your eye is shaped more like a football or the back of a spoon, light gets bent more in one direction than another. That means only part of an object is in focus. Objects at a distance may look blurry and wavy. It’s fairly easy for an eye doctor to fix with glasses, contacts, or surgery.

What Causes It?

It’s totally natural and most people are born with it. We don’t know the exact cause. You can also get it after an eye injury, eye disease, or surgery. There’s a myth that you can get it if you read in low light or sit too close to the TV, but that isn’t true.

Astigmatism2

What Are the Symptoms?

Blurry vision. You might chalk it up to fatigue or eyestrain, but it’s the major sign of astigmatism. If you can’t see clearly, schedule an eye exam to find the source of your problems.

How Is It Diagnosed?

You’ll need a thorough eye exam. Your doctor may also find another problem -- you could be nearsighted or farsighted. Because astigmatism symptoms come on slowly, you should go to an eye doctor if you notice changes in your vision.

How Is Astigmatism Treated?

Almost all cases can be corrected with glasses or contacts. But if you only have a slight astigmatism -- your doctor may refer to it as a degree -- and you don’t have another vision problem, you may not need them.

Irregular astigmatism is far less common and is linked to problems with your cornea, the front part of the eye. A common one is keratoconus, in which your normally round cornea becomes cone-shaped.

There are two treatments for the common levels of astigmatism:

Corrective lenses. That means glasses or contacts. If you have astigmatism, your doctor will probably prescribe a special type of soft contact lenses called toric. They can be made to bend light more in one direction than the other. If your case is more severe, you might go with a gas-permeable rigid contact lens. Your eye doctor will figure out which one is best for you.

Refractive surgery. This laser surgery changes the shape of your cornea. There’s more than one type, so your doctor will help you pick the one that’s right for you. You’ll need to have healthy eyes with no retina problems or corneal scars.

WebMD Medical Reference Reviewed by Alan Kozarsky, MD on September 20, 2016

Sources

SOURCES:

Yanoff, M. Ophthalmology, Mosby, 2008.

MedlinePlus: "Vision Problems."

National Eye Institute: "Facts About Refractive Errors."

American Academy of Ophthalmology: “What Causes Astigmatism?”

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