Testing for Astigmatism and What Comes Next

Astigmatism is a common refractive eyesight error, affecting up to a third of Americans. Most people with astigmatism do not experience symptoms because their condition is so mild. But if you have blurry vision with eye strain or headaches, astigmatism could be the cause.

A comprehensive eye exam is the gold standard for testing for astigmatism, an irregular curvature of the eye’s cornea or lens. Your doctor will perform a series of tests to assess both your eye health and refraction quality.  

Because several eye health conditions can cause blurry vision, comprehensive testing in a doctor’s office is the best way to determine if you have astigmatism. Recently developed online tests can screen for refractive errors but cannot replace the detailed in-office testing your doctor can provide. 

If you have astigmatism, glasses, contacts, or surgeries like LASIK could help you see clearly. 

How to Test for Astigmatism 

Evaluation for astigmatism begins with your doctor taking a detailed patient history that includes any eye symptoms you are experiencing, the duration of the symptoms, and your overall health. A family history of astigmatism is also relevant.

Then, your doctor will perform several tests to determine if you have astigmatism and how significant it is. 

Eye Chart

A Snellen chart helps your doctor measure your visual acuity, or distance vision. 

Your doctor will place the chart 20 feet away and ask you to read the letters you see. The letters get progressively smaller (and potentially harder to discern).

The result of visual acuity testing is expressed as a fraction. For instance, if you have a visual acuity of 20/20, you have standard vision. 

However, people with astigmatism often complain of blurry vision. Your results could be worse than 20/20 as a result. 

Phoropter

Your doctor places a large device in front of your eyes containing many lenses and dials. Your doctor will manipulate these tools, asking you to focus on a letter and call out when the image is sharp. 

This tool helps your doctor understand what strength of lens might give you sharper vision.

Autorefractor

Using a very bright light, your doctor uses an autorefractor tool to measure how the light shifts and curves as it bounces off the back of your eye and returns to the front.

Keratometer

Your doctor uses this sophisticated tool to measure the curve of your cornea. You’ll lean into a headpiece and open your eyes wide. Your doctor will look through a lens as a bright light shines into the eyes. The data will give your doctor more information about your cornea’s shape.

Advanced Testing

Your doctor can perform a corneal topography exam, creating a very detailed map of the hills and valleys on your cornea’s surface. This information could be particularly useful if you’re planning a surgical correction for astigmatism. 

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How Do At-Home Tests & Online Tests Compare?

A doctor’s visit is the best way to determine if you have astigmatism. But it’s not your only choice. 

Bloggers and DIY websites are filled with information about building astigmatism testing kits. And some companies offer at-home tests too. 

The benefits of at-home tests include the following:

• Speed: You don’t have to wait for a doctor’s appointment to find out if you have astigmatism. Get the results in minutes. 
• Cost: DIY astigmatism checkers are incredibly cheap. Make the easiest version out of paper fasteners, tape, and paper. 
• Comfort: No eye dilation, poking, or prodding is required for these astigmatism tests. 

But the drawbacks of at-home tests can be significant. They include the following:

• Limited scope: An at-home test can only tell you if you have astigmatism, not if you have another condition blurring your vision. 
• Inaccurate results: Make a mistake, and the tool you build won’t tell you anything at all. 
• More work required: If you do have astigmatism, an at-home test can’t write a prescription for glasses or schedule you for surgery. Only a doctor can do that.

What Happens if I Am Diagnosed With Astigmatism?

If you’re diagnosed with astigmatism, you have choices. Your doctor will explain them to you and help you make a smart decision based on factors like your visual acuity, line of work, and hobbies. 

Your treatment options include the following:

• Nothing: Not all cases of astigmatism require treatment. If you’re fine with slightly blurry vision, you’re not required to get any kind of correction. 
• Glasses: Lenses in front of your eyes refocus light on your retina, allowing you to see clearly despite your astigmatism. 
• Contact lenses: Contacts work much like glasses, but they sit on your eye’s surface. Harder versions, such as rigid gas-permeable contacts, are often recommended for people with astigmatism. 
• Refractive procedures: Surgeries like LASIK involve using a laser to reshape the cornea and smooth curve problems caused by astigmatism. Surgery is a permanent correction. 

What if Tests Are Normal?

Astigmatism is just one potential cause of blurry vision. If the astigmatism tests are normal, your doctor may identify another condition that is changing your vision.

Macular degeneration, glaucoma, and retinopathy also cause visual disturbances. Therefore, your doctor will perform tests such as slit lamp examination and tonometry to determine the cause of your eye symptoms.

FAQs About Testing for Astigmatism

References

1. Eye Health Statistics. (2015). American Academy of Ophthalmology.

2. What Is Astigmatism? Symptoms, Causes, Diagnosis, Treatment. (August 2022). American Academy of Ophthalmology.

3. All About the Eye Chart. (March 2022). American Academy of Ophthalmology.