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What is Astigmatism?



If you have been told you have astigmatism, you are not alone. The truth is most people do have this problem to some degree, but it doesn’t always affect vision enough to require correction. Astigmatism is often associated with common vision issues like myopia or hyperopia, though. What is astigmatism and how does it happen?


What is Astigmatism?

Astigmatism refers to an imperfection in the curvature of the eye. In a perfect world, everyone’s eye would be round like a ball. When the eye is shaped just right, both the cornea and lens have the same curve to them. This allows light to enter the globe and hit the lens at an ideal angle.

It’s not a perfect world, though, so most people have eyes shaped more like an egg. In other words, the cornea is curved differently than the lens. This is astigmatism in a nutshell. When the eye globe shape is more oblong than round, it affects how light refracts and you don’t see as well.

There is no clear-cut answer to why some people get astigmatism, but most are born with it. It can also occur after an injury to the eye, disease or a surgical procedure.

The measurement for astigmatism is diopter. A cornea shaped like a ball has zero diopters. A person with 1.5 or more diopters usually needs some type of correction to see clearly. Sometimes, as a person ages, the shape of the lens changes and this may increase or decrease astigmatism. The doctor will look for astigmatism as part of your comprehensive eye exam in Birmingham using instruments that check the curvature of the cornea, visual acuity and refraction.


What are the Symptoms of Astigmatism?

You could have astigmatism and not even know. This is especially true for children. They may have blurry vision without realizing it’s abnormal. In general, the symptoms include:

  • Distorted vision

  • Eye discomfort

  • Fatigue

  • Headaches

  • Poor night vision

  • Squinting


How is an Astigmatism Treated?

The treatment plan depends on a number of factors, but the goal is to improve your eyesight and eye comfort at the same time. Treatment options include:

  • Eyeglasses – Eyeglass lenses compensate for the curvature issue by bending light in a way that works for your eyes.

  • Contact lenses – Similar to eyeglasses, contacts correct the error and are custom designed to fit each person

  • Orthokeratology – Patients wear specially designed rigid contact lenses for just a few hours a day. The lenses temporarily change the shape of the cornea.

  • Refractive surgery – Patients looking for a permanent solution will want to consider refractive surgery, which effectively eliminates the need for any corrective lenses. With surgery, the doctor uses a laser to reshape the cornea, which corrects the curvature error. This surgery is done on an outpatient basis and comes with very few risks, but it might not be right for everyone.


If you have astigmatism that is affecting your vision, it’s time to make an appointment with a board certified ophthalmologist like Dr. Young H. Choi in Birmingham.



* All information subject to change. Images may contain models. Individual results are not guaranteed and may vary.