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What Is Astigmatism?

astigmatism of the eye

Story at-a-glance -

  • Astigmatism is not an eye disease or a health problem. Rather, it just means that there’s a defect in how your eyes focuses light due to its irregular shape
  • In fact, the American Academy of Ophthalmology states that as many as 1 in 3 people have this refractive error, along with near or farsightedness

Have you ever experienced having blurry or fuzzy vision at certain distances? When nighttime comes, do you have trouble seeing things around you, such as when you’re driving? If you’re experiencing these symptoms,1 then you may have a common problem of the eye called astigmatism. But what is this health condition, and should you be worried?

Basic Facts on Astigmatism

The word astigmatism may sound scary, but in reality, it only means one simple thing: Your eye isn’t completely round. Astigmatism is not an eye disease or a health problem. Rather, it just means that there’s a defect in how your eyes focus light due to their irregular shape.

A normal eyeball has a perfectly circular shape, allowing light to enter and bend evenly, so you have a clear view. However, some people have eyeballs that are shaped more like the back of a spoon or a football. In this case, the light tends to become more bent in one direction than another.

As a result, the light fails to come to a single focus on the retina to give you clear vision; instead, multiple focal points, either in front or behind the retina, or sometimes both, occur.2 This causes only one part of the object to be in focus, while those at a distance appear wavy and blurry. This is what’s called astigmatism.3

Astigmatism is fairly common, and the American Academy of Ophthalmology states that as many as 1 in 3 people has this refractive error, along with near or farsightedness.4 There are several different types, but the three most common are mixed, hyperopic and myopic astigmatism.5

A blurry eyesight is the primary symptom of astigmatism, with many people often blaming it on eyestrain or fatigue.6 Other symptoms may manifest, though, such as eye irritation, frequent squinting and headaches.7

What Causes Astigmatism?

Astigmatism can occur both in children and adults. No one knows exactly what causes it, although genetics has been pinpointed as a primary cause. There are other risk factors, such as a history of eye surgery or an eye injury. This condition commonly occurs along with farsightedness or nearsightedness.8

In addition, the lens’ curvature inside the eye can change over time, leading to an increase or decrease in astigmatism. This usually happens during adulthood and may precede the formation of naturally occurring cataracts.9

How Can You Diagnose and Treat Astigmatism?

To confirm if you have astigmatism, an ophthalmologist or optometrist will conduct a comprehensive eye examination. This can include:10

  • Visual acuity assessment test — The doctor will ask you to read random letters on a chart to measure how well you see them.
  • Refraction test — You will use an optimal refractor machine, which contains different corrective glass lenses, to read a chart. Your doctor will adjust the lenses until they find one that suits your vision.
  • Keratometry — A keratometer will be used to measure the curvature of your cornea.

The good news is that astigmatism can be corrected. Corrective lenses like glasses and contact lenses are the most commonly prescribed, least invasive remedies for this eye condition. In some cases, surgery like LASIK may be advised, but this is highly invasive and is usually reserved for severe astigmatism cases.


Astigmatism: Introduction

What Is Astigmatism?

Astigmatism Symptoms

Astigmatism Causes

Astigmatism Test

Types of Astigmatism

Astigmatism Treatment

Contact Lenses For Astigmatism

Astigmatism Prevention

Astigmatism FAQ

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