Fayetteville, Pennsylvania – Problems reading or blurry vision? This trick tells you if you urgently need an appointment with an optometrist to check your eye health.

Ophthalmologist Dr. Brittani Carver loves to use TikTok to educate the public about all things eye health.

In her latest video, she reveals how you can tell if you have astigmatism.

This is when a difference in the curvature of the cornea results in distorted vision, nearsightedness, farsightedness, and in some cases even migraines.

In most cases, astigmatism is passed through genetics.

"Astigmatism is when your eye is shaped like a football, it can cause blurry vision, but can be corrected with glasses or contacts" Carver explains.

But how exactly do I find out I'm suffering from astigmatism?

In the clip, Carver shares an image of a star shape made up of several black lines.

First, she says viewers should look at the image with their left eye before repeating the exercise with their right.

"Any lines that are darker or blurrier or stand out. If you see any lines either up and down or side to side that are standing out that is a screening test to let you know that you do have astigmatism," she said.

More than 3 million users viewed the clip on TikTok within a day, and some are more than surprised by the results of the self-test. "Got it in my left but not my right," reports one user.

Another writes: "I took the test even though I already know, and yes, I really do have astigmatism."

If you've tried the test yourself and think you've discovered a vision problem, you should see an optometrist or ophthalmologist and have it checked.