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What Causes Astigmatism to Worsen?

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A young woman standing hunched over, and she's squinting to see even though she is wearing glasses

There are a lot of conditions that can cause blurry vision. Myopia makes distant objects appear blurry, while hyperopia and presbyopia can make it difficult to see things nearby. If you have blurry vision at every distance, however, it could be due to astigmatism.

Astigmatism is a common eye condition, typically diagnosed with a comprehensive eye exam, where an irregularly shaped cornea or lens changes how light focuses through the eye. While it’s typically a manageable condition through prescription glasses or contact lenses, factors such as eye injuries, keratoconus, and aging can cause astigmatism to worsen.

What Is Astigmatism?

Astigmatism occurs when the shape of your eye’s cornea or lens is irregular. Your cornea is your eye’s clear front dome, and your lens rests just inside your eye. When they’re misshapen, light may not correctly travel through your eye to your retina, leading to blurred vision. This blurriness can also cause eye strain and headaches as you try to focus on the world around you.

Astigmatism can happen to anyone. Most people who have astigmatism are diagnosed as children, but it’s not rare for adults to develop it independently. Some factors that can increase your risk of astigmatism include:

  • A family history of astigmatism
  • Keratoconus
  • Corneal scarring
  • Corneal thinning
  • High amounts of nearsightedness (myopia)
  • High amounts of farsightedness (hyperopia)
  • Previous eye surgery
Two similar images comparing what a bridge would look like with normal vision and what the bridge would look like if the person had astigmatism

How Do Optometrists Diagnose Astigmatism?

A visual acuity test is typically an optometrist’s first step in diagnosing astigmatism. During a vision test, your optometrist may ask you to read letters on a chart from a specific distance. If you have astigmatism, you may find it difficult to read the letters or see them clearly. Your optometrist can use this information to make some preliminary determinations about whether you may have astigmatism. But this is just the beginning! We have many more fun diagnostic tools at our disposal.

One such diagnostic test is keratometry, where your optometrist measures the curvature of your cornea, which influences how light enters your eye. Optometrists use a keratometer to measure the cornea’s curvature and determine where it’s the steepest and flattest.

In some cases, we may even make a detailed map of the cornea using corneal topography. Your optometrist can use a special instrument to shine a light on your eye and capture its reflection. We can then use this information to create a 3D map of your cornea’s surface, which we can use to diagnose astigmatism—and other eye conditions.

Can Astigmatism Worsen?

Unfortunately, prescriptions can change, which is why you should visit your optometrist regularly for eye exams. Astigmatism is no different. A few factors can cause your astigmatism to worsen, including your age, eye injuries, and keratoconus.

While most people are diagnosed as children, you may notice your sight worsening as an adult too. Astigmatism can also decrease, so it’s not all bad news!


We all know that getting old has its challenges, but one of those challenges can be your sight. As you age, your cornea can change shape, which can worsen astigmatism. Blame it on the wear and tear of a lifetime of use! Experts aren’t entirely sure why this happens, but it appears to be due to changes in your eyelid tension and eye muscles.

Eye Injuries

Our eyes are powerful tools, yet unfortunately delicate. Sure, we try to keep them safe, but accidents happen. Some common eye injuries include foreign objects in the eye, chemical burns, blunt force trauma, or side effects after eye surgery. These injuries can cause damage to your cornea, lens, or retina, which can worsen existing astigmatism.

For example, if your cornea is scratched, it may heal irregularly, causing the shape of your cornea to change and worsening astigmatism. Similarly, if your lens is damaged, such as by blunt force trauma, light may refract unevenly, resulting in distorted vision and worse astigmatism.


Keratoconus is a condition where your cornea becomes thinner and weaker, causing it to bulge outwards in a cone shape. This change in shape can distort light as it enters your eye. If that sounds familiar, it’s because we’ve been talking about something very similar, astigmatism!

Since astigmatism itself can be caused by an irregular shape of the cornea, when someone with keratoconus also has astigmatism, the cone-shaped distortion in their cornea often makes astigmatism worse.

Keratoconus is fairly rare, though, and the cause is unknown. There appears to be a genetic component, but it’s also been linked to:

  • Eye allergies
  • Aggressive eye rubbing
  • Disorders affecting the eye’s connective tissue

Treatments for Astigmatism

Eyeglasses are often the first option for treating astigmatism, particularly for those with low to moderate levels of astigmatism. The lenses in your glasses can correct how light enters your eye to improve your vision. Glasses have come a long way in recent years and there are plenty of stylish frames available to choose from!

If you’re not a fan of glasses, you may want to consider contact lenses as an alternative. Though eyes with astigmatism used to be hard to fit, modern contact lens technology has provided more options than ever. Rigid gas-permeable (RGP), aspheric, and toric contact lenses can all be excellent choices for vision correction with astigmatism.

For those with more severe cases of astigmatism, laser eye surgery may be a good option. Refractive surgery, like LASIK and PRK, reshapes the cornea to help eliminate astigmatism. This could result in clear vision without the need for glasses or contact lenses. 

Unfortunately, not all people with astigmatism are good candidates for refractive surgery. We can help determine if this treatment is right for you.

Proactive Eye Care for Healthy Vision

Your sight can change over time, but you can stay on top of things with the help of The Eye Care Team! We can examine your eyes and watch for changes in your vision. With prevention and education, we’re here to help care for your sight with impressive diagnostic technology and innovative treatments.

Let’s make a difference in your eye care—book your eye exam today!

Written by Dr. Daniel Evans

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