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Understanding What Level of Astigmatism Requires Glasses

If you’ve just been diagnosed with astigmatism, you may be wondering what that means. There’s no need to worry though and you’re not alone. More than a third of people in the U.S. suffer from astigmatism. It’s a common eye condition that’s easily addressed with the right eyewear — assuming it’s even serious enough to do anything about. This brings us to the question: What level of astigmatism requires glasses?

Let’s define exactly what astigmatism is and discuss the types you might have. We’ll also clarify the different levels you may experience, and exactly what level of astigmatism requires glasses. 

What Is Astigmatism?

A perfect eye is basketball-shaped. It’s evenly round, so when light rays hit it, that light moves through the cornea and lens, and hits the focal point on your retina in exactly the right way. A signal gets sent from there to your brain, which gives you a clear image and interprets what you’re seeing.

But if the curvature of your cornea or lens is slightly irregular, the light scatters rather than hitting one point. That refraction can result in multiple focal points, making it difficult to focus properly.

The two types of astigmatism are slightly different.

Corneal astigmatism is the most common type. If you have regular corneal astigmatism, your cornea may be slightly flattened but still symmetrical — more like a football than a basketball. With irregular astigmatism the shape may be more uneven, perhaps bulging out slightly to the one side. This is most often caused by an eye injury, rather than being inherited.

With lenticular astigmatism, the cornea might be a regular shape but the crystalline lens is slightly distorted. This is less common but results in the same kinds of symptoms.

With either kind of astigmatism, you’re likely to experience refractive errors that can cause a variety of vision problems.

Symptoms of Astigmatism

Depending on your eyes and how serious the astigmatism is, you could experience any of these symptoms:

  • Fuzzy or blurry vision

  • Distorted vision

  • Shadowy images

  • Difficulty with night vision

  • Halos, streaks, or glares around lights, especially at night

  • Squinting

  • Eye strain or fatigue

  • Headaches

Many people with astigmatism only have very mild symptoms — like very slightly blurred vision — that don’t interfere with their daily activities or quality of life. 

If you’re experiencing any of the above symptoms though and you care about your eye health, it’s worth a trip to your optometrist. They’ll do an eye exam to establish how serious your astigmatism is. A good eye doctor knows exactly what level of astigmatism requires glasses and will be able to advise you on your next steps.

How Astigmatism Is Measured

What level of astigmatism require glasses: patient consulting an optometrist

Astigmatism is measured in units called diopters. A perfectly round eye will have a measurement of 0 diopters of astigmatism. Most people have up to 0.75 diopters of astigmatism — this is normal and doesn’t require any correction.

The number of diopters then increases with the severity of astigmatism:

  • Mild astigmatism: 0.75-2 diopters

  • Moderate astigmatism: 2-4 diopters

  • Severe astigmatism: 4 or more diopters

What Level of Astigmatism Requires Glasses?

Now that we’ve clarified how astigmatism is measured, the answer to the question “what level of astigmatism requires glasses?” is: anything above 1.5 diopters.

You’ll see your diopter number on your prescription, along with two other numbers. 

Astigmatism often goes with either myopia (nearsightedness) or hyperopia (farsightedness), so if your eye doctor recommends glasses to address any combination of those, your optometry prescription is likely to have these three numbers on it:

  • Spherical number: Strong prescriptions have high spherical numbers. If you’re farsighted, your spherical number will have a plus sign in front of it, and if you’re nearsighted, it will have a minus sign.

  • Cylinder number: This shows the diopters, indicating the degree of astigmatism based on your corneal irregularity.

  • Axis: This shows the degree of the cornea at which the astigmatism is located.

Astigmatism is often inherited, so you may have had a mild version your whole life. Your level of astigmatism can change over time though, as you get older and start to lose muscle tone in your eyelids — which play a surprisingly big role in keeping your cornea in the right shape. 

It might also change if you suffer from an eye injury, or if you develop a corneal disorder like keratoconus or keratoglobus, or an eye disease like a cataract or tumor. That’s why one of the most important elements of eye care is a regular check-up with your eye doctor.

How to Correct Astigmatism

Man wearing glasses

Once you know if your level of astigmatism requires glasses, you can explore ways to correct astigmatism. Luckily there are multiple treatment options to restore clear vision, with one of the most effective being eyeglasses.

Eyeglasses for Astigmatism

In case you’re wondering, over-the-counter reading glasses are designed to deal with presbyopia, not astigmatism. Normal single vision lenses won’t help either. If you have astigmatism, you’ll need cylindrical or spherocylindrical corrective lenses. These are manufactured with a specific curve, based on your prescription, that compensates for the irregular shape of your eye. This corrects the way that the light bends, allowing you to focus properly.

Contact Lenses for Astigmatism

If you go with contact lenses, your best bet is a type of soft contact called a toric lens. These stay in place regardless of the shape of your eye. If you have severe astigmatism though, your optometrist might suggest hard lenses instead.

Eye Surgery for Astigmatism

For more permanent vision correction, you might opt for refractive surgery — also known as LASIK surgery (laser in situ keratomileusis). This would normally be performed by an ophthalmologist and although there are many benefits, it can only fix existing conditions. So you may develop other refractive errors after the surgery, as your eyes change further.

Where to Get Your Glasses for Astigmatism

Woman holding 2 pairs of glasses

Now that we’ve answered the question of what level of astigmatism requires glasses, we can look at where to get those glasses. Once you have a prescription from your optometrist, visit Pair Eyewear for the most versatile collection of eyeglasses out there.

Choose from a selection of Base Frames, then add your choice of stylish Top Frames to complement your personality and complete your look. Once you’ve chosen your frames, provide your prescription (be sure to input it correctly, especially if you have astigmatism) and we’ll make your glasses to fit your requirements.

Correct Your Astigmatism With the Right Glasses for You

Astigmatism is a common eye condition caused by an irregularity in the shape of your cornea or lens. This can result in a variety of different symptoms, ranging from blurry vision to headaches.

The severity of your astigmatism is measured in diopters. When it comes to what level of astigmatism requires glasses, you’ll probably need them if you have more than 1.5 diopters of astigmatism.

You can opt for a more permanent solution like eye surgery, but for most people this condition is most easily corrected with eyeglasses or contact lenses. Get the right prescription from your optometrist, then choose glasses you love, like Pair Eyewear, so you can’t wait to wear them every day.