How Does Astigmatism Affect Your Night Vision?

Experts call astigmatism a “refractive error.” That’s essentially a fancy way of saying that your eye doesn’t bend or refract light rays correctly.

There are two main types of astigmatism: corneal and lenticular. With corneal astigmatism, your cornea has more of an oval shape instead of a round shape. With a lenticular astigmatism, it’s your lens that is misshapen.

The irregular shape of your cornea or lens prevents your eye from being able to focus light correctly on your retina. Your retina is the area at the back of your eye that converts light into signals that are sent to your brain for visual recognition.

You can be nearsighted or farsighted and have astigmatism, too. They’re all considered refractive error conditions.

The most common symptom of astigmatism is blurry or distorted vision, both close up and at a distance. You may also have a harder time seeing clearly at night.

If you’ve ever noticed problems like glare from the headlights of oncoming cars or halos around streetlights, you’ve experienced some of the ways that astigmatism can affect your eyes at night.

So, why does this happen? At night, and other low light situations, your pupil dilates (gets larger) to allow in more light. When this happens, more peripheral light enters your eye. This causes more blurring and glare, and makes lights look fuzzier.

You don’t need astigmatism to have trouble seeing well in the dark. Many people have some trouble seeing well at night. In fact, many other eye diseases and disorders contribute to impaired night vision, including:

• nearsightedness (myopia)
• cataracts
• glaucoma
• keratoconus, a severe curvature of the cornea

Because of the way astigmatism can affect your vision at night, driving can be particularly tricky after dark. Some of the effects you may notice while driving at night include:

• lights and other objects may look blurry or fuzzy
• lights may have halos around them
• lights may appear streaky
• increased glare from lights
• increased squinting to see more clearly

Be sure to notify your eye doctor if you start having trouble with your night vision, or if you notice any of the symptoms above.

If you’re having trouble seeing lights and objects clearly, especially at night, the first step is to see an eye doctor. They can test your vision and determine if you have astigmatism, and to what degree. Or, they may determine that you have a different eye condition that affects your vision.

If you have mild to moderate astigmatism, your eye doctor may prescribe corrective lenses for you. Options for corrective lenses include:

• Eyeglasses. These will have lenses that help correct the way light bends into your eye. The lenses in eyeglasses can also correct other vision issues, like nearsightedness or farsightedness.
• Contact lenses. Contact lenses can also correct the way that light bends into your eye, allowing you to see more clearly. There are many different types to choose from, including soft disposable lenses, hard gas permeable, extended wear, or bifocal contact lenses.
• Orthokeratology. With this treatment, you wear rigid contact lenses, typically while you’re sleeping, to temporarily correct the shape of your cornea. Once you stop wearing the lenses, your eye will return to its former irregular shape.
• Toric lens implant. An option for people with astigmatism and cataracts, this surgical procedure involves replacing your eye’s misshapen lens with a special type of lens that corrects the shape of your eye.

If you already wear glasses or contact lenses that correct your astigmatism, your doctor will encourage you to wear those when driving at night. It’s also possible that you may need your prescription slightly adjusted if you’re having more trouble seeing lights and objects clearly at night.

You may have heard about night driving glasses, which are advertised all over the internet. The yellow-tinted lenses of these glasses are meant to cut glare and help you see better at night.

However, according to a 2019 study, they may not be as effective as they’re claimed to be. Although the study had a relatively small number of participants, it found no benefit to wearing night driving glasses.

None of the 22 drivers in the study noticed any improvement in their ability to see pedestrians at night, or any reduction in the glare of oncoming headlights as a result of wearing the glasses.

Astigmatism can make your vision blurry and particularly affect your night vision. You may notice that lights look fuzzy, streaky, or surrounded by haloes at night, which can make driving difficult.

If you do have astigmatism and notice that you’re having trouble seeing lights properly at night, it may be time to chat with an eye doctor. If you have a prescription for glasses or contact lenses, they may need an update. And if you don’t wear corrective lenses, it may be time to start.

Your eye doctor will be able to accurately diagnose your vision and advise you on the best options to correct your eyesight.