Have you ever been puzzled as to why you notice light beams originating from almost any lightbulb you come across? So, my friend, you are most certainly a member of a very specific population.

Whether it’s first thing in the morning or late at night, nearly one-third of Americans experience symptoms such as squinting to see well, headaches, difficulty seeing at night, and hazy vision.

This latter symptom may lead you to perceive beams extending from a light source, similar to the lights seen in this shot submitted on Reddit:

The image, which was published on the subreddit r/InterestingAsF*ck, depicts light coming in straight lines from lights scattered across the area. It depicts what some individuals would have observed at the incident, but not everyone.

Those who see these lights most likely have astigmatism, which occurs when your cornea (the transparent front layer of your eyeball) or lens (within your eye) has a different shape than usual.

While a normal eye is totally round, those with astigmatism have eyes that are egg- or oval-shaped, like an American football.

Although moderate astigmatism is unlikely to create symptoms, the aberrant shape of the lens or cornea caused by the disease can cause light to bend as it enters the eye, resulting in a refractive error.

“I always thought this was normal,” one Reddit user said after viewing the photo. “For example, when it rains at night, the street lights look like big red and green stars stretching further because of the raindrops on the windshield.” Then I discovered I have astigmatism, which makes me assume that not everyone notices the glare.”

You should not be alarmed if this describes your situation.

According to the Mayo Clinic, astigmatism is prevalent, with some people being born with it and others developing it as a result of an eye injury, disease, or surgery.

Doctors aren’t sure why the shape of the lens or cornea varies from person to person, but the risk of developing it is inherited from parents.

You may find out whether you have astigmatism for sure by attending an eye checkup with an optician, where testing may include reading from an eye chart or seeing through a device called a ‘phoropter,’ where you must relay which letters you can see better.

An autorefractor, which shines a light into the eye, and a keratometer, which measures the curve of your cornea, are two more tests that may be performed.

If you do have the issue, your doctor may be able to cure it using glasses, contact lenses, or even surgery to modify the curvature of your cornea.

If your astigmatism is slight, you may not require treatment.