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Astigmatism

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In normal vision light focuses on the retina, but in astigmatism  it focuses in more than one placeAstigmatism is a very common condition that causes blurred vision because of the shape of the cornea or lens in the eye.

In a normal eye, light focuses on one spot on the light-sensitive layer at the back, called the retina. This gives sharp, clear vision. With astigmatism, the light focuses on several spots, which means you see fuzzy, blurred images.

Usually this happens because the front surface of your eye (the cornea) has an irregular or rugby-ball shape (called corneal astigmatism). Occasionally the lens inside your eye may be tilted (called lenticular astigmatism). Whatever form of astigmatism you have, things will appear fuzzy or shadowy.

Astigmatism can happen with short-sightedness (myopia) or long-sightedness (hyperopia). Some people are born with it, but it can also develop gradually as you're growing.

Symptoms of astigmatism

If you have astigmatism, you may notice:

Diagnosing astigmatism

If you have any of the symptoms listed above, see your optometrist for an eye examination. This will show what is causing any vision problems, including astigmatism.

Treating astigmatism

The treatment for astigmatism adjusts your focus precisely onto your retina, so you can see sharp images instead of fuzzy ones.

Corrective lenses (glasses or contact lenses) change the way light focuses into your eye, and refractive surgery (laser surgery) reshapes the surface of your eye so light focuses onto your retina.

Glasses

Prescription glasses can correct both corneal astigmatism (when your cornea is an irregular shape) and lenticular astigmatism (when the lens inside your eye is tilted). Depending on how serious your astigmatism is, you may need to wear them all the time, or you may only need to wear them when you're concentrating on a specific task.

It can take a while to get used to glasses for astigmatism because as well as making your vision sharper, the glasses may slightly distort your vision for a few days. For example, a round plate might look oval or a flat table might seem bowed. Most people get used to this quickly, but some people need to have their prescription changed slightly. Your optometrist will talk with you about this when deciding which treatment option suits you best.

Contact lenses

There are many different types of contact lenses available, in both hard (rigid, gas permeable) and soft (usually disposable) materials. They include options for extended-wear prescriptions. Ask your optometrist which ones will be best for you.

Refractive surgery

Refractive surgery can permanently reshape the surface of your eye, using methods such as LASIK, PRK and LASEK. Ask your optometrist for more information. They can assess if you're suitable for surgery and refer you to a specialist eye surgeon if appropriate.

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Written by Canterbury optometrists. Adapted by HealthInfo clinical advisers. Last reviewed March 2023.

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