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What Causes Astigmatism To Worsen?

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Someone holding up a pair of glasses with the surrounding city background blurred out but sharp focus through the lenses of the glasses to simulate astigmatism

Astigmatism is a common condition typically treated with glasses or contact lenses. However, astigmatism can progress with time and affect your vision. If you have astigmatism, what causes this condition to worsen? 

Continue reading to learn more about astigmatism, including how this condition can become worse over time. 

What Is Astigmatism? 

Astigmatism is a condition where your cornea or lens isn’t round. This abnormal shape causes light to bend improperly. Incoming light refracts in more than one direction, making your vision appear blurry. 

Astigmatism usually develops in childhood and has several associated symptoms, including: 

  • Blurry or distorted vision
  • Eyestrain
  • Headache
  • Difficulty seeing at night

Who Is At-Risk of Astigmatism? 

While anyone can develop astigmatism, some people are more at risk than others. You have a greater likelihood of developing this condition if you have

  • A family history of astigmatism or keratoconus 
  • A scarred or thin cornea
  • Excessive myopia
  • Excessive hyperopia
  • A history of eye surgery, such as cataract surgery

Astigmatism can leave you with headaches, eyestrain, and blurry vision. Many people with this condition have it from childhood, so what causes astigmatism to develop? 

What Causes Astigmatism? 

Your eyes have 2 structures (the cornea and the lens) that bend light onto your retina, creating the images you see. Astigmatism occurs when there is an issue in one or both parts of the eye. This condition is often present from birth—it can be hereditary

Your cornea is the clear front surface of your eye, and the lens is a clear structure inside of your eye that changes shape to help you focus on nearby objects. The cornea and lens usually have round curves, similar to a ball. This shape allows you to see a clear and focused image. 

If the lens or cornea has mismatched curves, it results in a refractive error.

Refractive Error

A cornea or lens with mismatched curves, like an egg, bends incoming light incorrectly. The different images from your eyes overlap and lead to blurry vision.  

Astigmatism occurs when the cornea or lens has a steeper curve in one direction than the other. The type of astigmatism you have depends on which structure has mismatched curves. 

While astigmatism is a refractive error, it can present alongside other refractive errors, such as: 


Rarely, a condition called keratoconus can lead to irregular astigmatism. The smooth surface of the cornea warps when this happens. 

Keratoconus occurs when your cornea begins to thin and bulge outward in a cone-like shape, resulting in blurry vision and light sensitivity. This condition can slowly progress with time. 

If you have astigmatism, what can cause this condition to worsen? 

A man in front of a blue wall with his glasses off holding a book as far away as possible while he squints to see the words on the pages

What Causes Astigmatism to Worsen? 

Astigmatism frequently worsens with age. Your cornea can become more irregular due to pressure from your eyelids as they lose muscle tone. 

Astigmatism generally stays stable until your turn 50. After then, your lens curvature progressively worsens each decade. Corneal and lens curvature gradually changes with time, meaning this condition will change as you age. 

While astigmatism does change with time, it’s still treatable. Your optometrist has several ways to manage your condition and help you see clearly. 

Astigmatism Treatment 

Treating astigmatism focuses on correcting your refractive error. Your optometrist has several ways to do this with corrective lenses, specialty contact lenses, and refractive surgery. 

Corrective Lenses

Corrective lenses include both glasses and contact lenses. Your optometrist can determine how much vision correction you require during a comprehensive eye exam. Your eye doctor can adjust your prescription as needed if your condition worsens. 

For contacts, different lenses are effective for astigmatism. Rigid gas permeable (RGP) lenses are ideal for astigmatism because they have a personalized design. Other corrective lenses include aspheric and toric contacts. 

Aspheric contact lenses can help someone with mild astigmatism—they have a unique shape that fits the eye’s curvature.

Toric contact lenses feature different prescriptions around the horizontal and vertical planes of the lens. They have a weighted bottom to help these focusing powers stay where they need to be on the eye as it shifts when you blink. 


Orthokeratology or ortho-k lenses are rigid contacts designed to treat refractive errors. They gradually improve your vision as you sleep by flattening and reshaping the cornea. You remove these lenses in the morning and enjoy clear vision. 

Refractive Surgery 

Refractive surgery is another option for astigmatism. There are 2 common types of surgery used, LASIK and PRK. 

LASIK is one of the most popular forms of laser eye surgery available today. During this procedure, your doctor creates a small flap in the cornea to reach the rest of the eye. They then reshape the cornea using a surgical laser. 

Photorefractive keratectomy (PRK) reshapes the cornea using a different approach. Your doctor begins by completely removing the outer layer of the cornea. They then reshape the cornea with a laser. 

Your optometrist can help you manage astigmatism. Don’t ignore any blurry vision or other signs of a refractive error—visit your eye doctor for a comprehensive eye exam. If you have symptoms of astigmatism, contact your optometrist.

Written by Dr. Daniel Evans

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