Is crossing your eyes really bad for you? We asked an optometrist.

When your mom told you to stop crossing your eyes as a kid or they’d stay stuck that way, was she right? Don’t tell her we said this: But nope. Go ahead and cross your eyes without fear, says Toronto-based optometrist Dr. Meenal Agarwal.

“Sometimes when my kids walk with their feet turned in, as a parent, we will say, ‘Come on, don’t do that,’” Agarwal says. “But is that permanently going to happen? No. It cannot physically, permanently change the way their feet are or their eyes are.” 

Our eyes are built to move in all kinds of directions, thanks to six muscles that make it possible for us to look up, down, sideways…or, ahem, in a crossed manner. 

When we cross our eyes, the medial rectus muscle is the primary player, Agarwal says. Each eye has one of these muscles sitting right next to the nose. We use them constantly in normal vision; they help each eye to turn inward when we look side to side. When you intentionally cross your eyes, you are just contracting both medial rectus muscles at once to make your eyes turn toward each other. 

But, again, Agarwal notes: Using both of your medial rectus muscles simultaneously will not make your eyes permanently crossed.

“Nothing bad is going to happen to you,” she says. 

When crossed eyes signals a problem

There is a difference between eye-crossing voluntarily while telling a joke—and eye-crossing that happens involuntarily. The latter could be a reason for medical concern.

In babies and infants: If a child’s eyes appear persistently crossed or the turning in is very noticeable and doesn’t resolve within the first few months of life, this could be a sign of an underlying issue, Agarwal says. Parents should take their child to a doctor to get it checked out, she advises. In babies, persistent crossed eyes may require surgery, and early treatment can be critical for vision to properly develop. “If it is very evident, you usually don’t grow out of it,” she says.

In young children: Uncorrected farsightedness is a common cause of crossed eyes. In her practice, Agarwal typically sees it in kids ages three to five, who are coming in for their first eye exam. When farsightedness isn’t corrected with glasses, the eye muscles strain to overcompensate, which can cause one or both eyes to turn inward, she says. Wearing eye glasses can fix it. 

“Your brain is making your eyes do that so that you can see,” she says. “But once you get glasses, that relaxes, and therefore you can see, and therefore you don’t have that turned eye anymore.” 

In adults: Sudden eye crossing can be a serious sign of a stroke, which can cause eyes to turn in involuntarily. “If you see a 50-year-old man with an eye turned in all of a sudden, alarm bells go on,” Agarwal says. “You’re off to the [emergency room] because he just had a stroke.” 

Depending on the severity of the stroke and with rehabilitation, the eye usually settles back into its usual position. “It depends on how heavy the stroke was,” she says. “I have seen people with that with complete vision loss.” 

At any age: Brain-related issues, such as tumors, lesions, or inflammation near the nerves that control eye movement, could result in a crossed eye. “Your eyes are the window to the body,” Agarwal says. 

Bottom line: if your eyes or your child’s eyes all of sudden involuntarily turn inward, it’s time to head to the doctor. But if you’re just crossing your eyes for the gag, go for it. They definitely won’t get stuck that way. 

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