There’s a viral tweet going around purporting to show the difference in vision for someone with astigmatism, compared to someone without.
The tweet, from @UnusualFacts, shows one image with glare from lights in a nighttime scene and another similar image without the glare.
“This is what people was Astigmatisms [sic] vs without,” the tweet says.
That caused a whole bunch of people to lose their shit, thinking they have astigmatism in their eyes.
But everyone seriously needs to calm down because according to Dr. Samuel D. Pierce, those images aren’t a good representation of astigmatism at all. And as president of the American Optometric Association and someone with astigmatism, he should know.
“To be perfectly honest, I don’t think it’s the best representation of the way astigmatism looks through the eyes of someone with astigmatism,” he told BuzzFeed News. “It did not look like astigmatism to me, and I can say that because I have astigmatism.”
First of all, let’s review what astigmatism is. It happens when your eye is shaped differently than what’s normal, causing a refractive error. Pierce said you can imagine it like you’ve cut a tennis ball in half and you squeeze it, changing the curvature. Basically it’s like having an extra-curvy cornea.
The effect is that objects appear blurry. There’s also more than one type of astigmatism, which affects in which direction the blurs appear.
Pierce said you can imagine looking at a full moon. If you have with-the-rule astigmatism, you’ll see little blurry ghost moons above and below the real thing. With against-the-rule astigmatism, the ghost moons are to the sides. With oblique astigmatism, they’d be at an angle, like at 10 and 4 o’clock on a watch.
The viral images, he said, look more like simple glare.
“Yes, it’s possible that someone can see blur that streams off an object, but the way that the picture was created, it really looks more like glare of of lights,” said Pierce.
“Astigmatism is not a source of glare, it’s a source of blur.”
Seeing lights the way they look in the image could point to a glare issue, cataracts, or even dirty contacts. Mostly, it doesn’t mean much.
Astigmatism itself is the most commonly diagnosed refractive error, and for most people, it’s mild and just a minor annoyance. Others with a worse case may have more trouble seeing and need corrective glasses or contact lenses.
The bottom line is that the only good way to diagnose eye issues is at your annual eye exam with an optometrist, not by looking at some viral photos on Twitter.
Dr. Samuel D. Pierce’s name was misspelled in an earlier version of this post.