Need an astigmatism test? Here’s how to do it.
The ins and outs of astigmatism
If you have blurry or distorted vision when seeing objects both far away and close-up, it's possible you may have an eye condition called astigmatism. Astigmatism is one of the most common visual impairments in the world, and while you can be born with it, you’re more likely to develop it as you age. But whether you’ve had it all your life or you’ve just discovered it, the good news is astigmatism is easy to diagnose and correct for most people.
What is astigmatism?
Let’s get a little science-y for a second. Each of our eyes works by bending light through its lens and onto its retina to project a clear image. The shape of its lens determines the amount of light that passes through, which in turn moves your visual image in and out of focus. A normal lens shape should be round and even like an olive.
With astigmatism, these light rays do not bend properly as they enter the front of the eye. This is usually due to the lens being shaped like an egg or a football. The two basic types of astigmatism are horizontal astigmatism (the eye is wider than it is tall) or vertical astigmatism (when the eye is taller than it is wide. Even a slightly oval shape can change your ability to bend light properly, resulting in a blurry image. The result is astigmatism.
Symptoms of astigmatism
You might be thinking, wait a minute—astigmatism isn't the only visual condition that causes blurred vision out there. So how do you know the difference? While eye conditions such as myopia (farsightedness) and hyperopia (near sightedness) also cause visual disturbances at specific distances, astigmatism causes blurred vision at any distance.
There's no agreed-upon way to measure the severity of astigmatism, but it does have a spectrum from mild enough that it may be difficult to notice to severe enough that seeing without vision correction becomes a challenge. While it may seem easier to detect a more obvious case of astigmatism, there are other, less obvious signs that can mean you are more likely to have it. These symptoms include:
- Habitual squinting to see things clearly
- Chronic eye strain
- Frequent headaches that don't seem to have other causes
- Trouble seeing under low light conditions, especially at night
Even if you have several of these symptoms, there’s no guaranteed that you have astigmatism. This is why it's a good idea to get regular eye exams and let your eye care professional get definitive answers for you.
Getting an astigmatism test
The best way to get an astigmatism diagnosis is to visit your eye care provider and have your eyes examined in person. The most common test for astigmatism involves shining an exam light into your eyes and measuring the way light bounces back. Since this test is largely influenced by your eyes' internal curvature, it can provide reliable results for the presence of astigmatism and give your provider an idea of how strong your astigmatism is.
Another common test for astigmatism involves a visual acuity exam, which calibrates how severe your astigmatism is and generates a prescription for glasses or contact lenses.
With a visual exam, you can often receive a prescription for glasses or contacts to correct your astigmatism, so it’s important to get your eyes examined so you can check your eye health and see clearly.
Online astigmatism test
It’s true that getting a proper diagnosis and taking corrective measures requires the help of an eye care professional, but you're not entirely out of luck if you haven't done this yet. There are ways to check for astigmatism at home, including an online astigmatism test you can do on your computer.
While only an in-person exam can be definitive, you can get a quick idea of how likely you are to have astigmatism at home with an online astigmatism test. An online test will not be as accurate as the comprehensive exam offered by your eye care provider, but it's a quick and easy way to check if your vision problems are consistent with astigmatism. It also has the advantage of being free or low-cost as well as available anytime you want to try it.
How an online astigmatism test works
It's not (yet) possible for your computer or smartphone to shine lights into your eyes and measure their curvature, but you can use common visual function tests to gauge how severe your visual impairment is. This isn't a proper diagnosis, but it can help you feel more confident about whether you've suffered vision loss and what the underlying cause might be. Online astigmatism tests generally work the same way, by testing how well you can see specific visuals on a computer screen and giving you a score based on your results.
Taking an online astigmatism test
For most tests, you should sit 2 or 3 feet away from the screen, assuming your monitor is displaying at the standard resolution, and alternate covering your left and right eyes while images are shown on the screen. Most online exams use a series of dark lines as test images, and they ask you to grade their thickness. If your vision is blurry, you'll get distorted answers, and the more distorted they are, the more likely it is you have astigmatism. The test also simulates the lines being far away and close up to check whether your vision is impaired at all distances or just at a specific range.
It's important to note that your results may vary slightly depending on your environment, so make sure to follow the instructions as closely as possible. If you sit too close or too far from the screen, cover the wrong eye, or have your monitor settings switched to high contrast or elevated magnification, you're unlikely to get an accurate result. And just like anything related to your health, remember that an internet test isn't the same as a medical assessment. The best use of an online astigmatism test is to decide whether it's time to get an in-person eye exam.
Getting treated by your eyecare provider
Finding the right vision correction for your astigmatism is simple. Schedule an appointment with your eye care provider and they’ll be able to talk to you about your options, which may include glasses, contact lenses, or corrective surgery. You might even be able to try a few different options to find out what you like best.
How to schedule an appointment with your provider
Your eye care office can schedule you for an appointment. Walk-in clinics may be another option, but you may have better luck scheduling your visit. When your eye doctor is ready to see you, they’ll examine your eyes with an ophthalmoscope while you view an eye chart from a distance.
As you look at the chart, your eye doctor will switch the lenses around to alter the way light bends before reaching your eyes. This is kind of like trying on different prescription glasses and seeing which ones work best. After your eye exam, your eye care provider may give you a prescription for glasses or contact lenses, which you can then use to order the eyewear of your choice either there in the office or anywhere else you have in mind.
Astigmatism is a common medical condition, but even so, your eye doctor will likely have the inside of your eyes checked by either an ophthalmologist or an optometrist, since these are licensed medical practitioners who can write prescriptions. Another eye care professional, the optician, may be present and guide you through the vision test, or they might fit your glasses for you as well.
Treatment options for astigmatism
If you find out you have astigmatism, no worries. There are several treatment options for astigmatism, which we mentioned above. Let’s go into a bit more detail to help you narrow it down.
- Glasses: Glasses have been around for centuries, ever since people learned how to grind glass to bend light. Your eye care professional can prescribe corrective lenses for you, which are then ground to spec and mounted into stylish frames of your choice. When you put the glasses on, you should be able to see clearer. With astigmatism, it can sometimes be tricky to correct your vision to its clearest, but they’re a great option that are easy to use and provide clearer vision the instant you wear them.
- Contact lenses: Contact lenses are like glasses, except they're smaller and you wear them on your eyes, rather than in front of your eyes in frames. Contacts are a great option for swimming, sports, or any other time you would prefer to not wear glasses but would still like to see. Whether you need higher vision correction or more mild correction, contacts are usually recommended for adults and teenagers.
- Refractive surgery: Astigmatism is caused by an abnormal curvature of the lens or cornea, so it's possible to fix with surgery. This is usually done by either slicing a flap open on the cornea and inserting a new lens, or by reshaping the lens with laser pulses. When it's done and you've recovered, you could have 20/20 vision without glasses. Your surgeon will be able to help you find out if corrective surgery is right for you.
Living with astigmatism
Depending on the severity of your astigmatism, you may be able to return to normal vision with routine corrective measures. First, you have to get the ball rolling with an eye exam, which you can do by finding an eye care professional in your area. They’ll be able to check your eyes and put you on the path to better vision.
FAQs
How accurate are online astigmatism tests?
Online astigmatism tests can give you an idea if you may have an astigmatism, which in that case, would be a good idea to get in for an eye exam. Remember, you can only get a definitive astigmatism test by an eye care professional, so, as tempting as it is, don’t self-diagnose!
Can astigmatism worsen over time?
Astigmatism can be a progressive condition that worsens as the years go by. If you've been diagnosed with astigmatism in the past, you should get regular eye exams to stay on top of your eye health.
Can children have astigmatism?
Kids can get astigmatism as young as 6 months old but can sometimes outgrow it. Because astigmatism can impact a child’s school performance, ability to play sports, and lead to lazy eye if left untreated, it’s important to have regular eye exams when they’re young to detect and treat any problems early on.