Staring at anything for long enough can lead to eye discomfort. But the stakes are higher for anyone who watched Monday’s solar eclipse sweep across North America. After much of the country spent the afternoon gazing up at the searing rays of the sun, it’s worth distinguishing between a bout of dry eyes and the more severe retinal damage that unprotected exposure can cause.

Experts told The Washington Post that anyone who followed the requisite safety tips and used proper solar eclipse glasses to view Monday’s spectacle should feel reassured that their eyes escaped any serious harm. But if any symptoms like soreness — or, more importantly, pain or blurriness of vision — persist, they strongly recommended checking in with an eye doctor.

Here’s what to know about why your eyes might be hurting after watching the solar eclipse.

I wore eclipse glasses but now my eyes feel sore or dry. Should I be worried?

If you’re experiencing headaches, soreness, pain or any other symptoms after watching the eclipse, it’s worth checking that you were adequately protected. Glasses that offer enough protection have the International Organization for Standardization (ISO) 12312-2 code inside, and the American Astronomical Society has a list of trusted manufacturers.

Knockoffs are out there. Ahead of the eclipse, Amazon on Friday emailed customers that a brand of glasses sold on the site, Biniki, had not been approved by the American Astronomical Society and “may not be safe for viewing a solar eclipse.” The Illinois Department of Public Health also warned Monday that Biniki glasses did not meet safety standards despite being sold online and in some stores.

If you wore approved glasses and only viewed the solar eclipse through them, it’s unlikely that your eyes were damaged, said Carl Jacobsen, a clinical professor at the UC Berkeley School of Optometry.

Some discomfort can come naturally from eyes drying out after focusing and staring at the eclipse for a long period, especially outdoors, Jacobsen said. Sore eyes can be treated with lubricating eyedrops.

Why is looking at the eclipse without glasses dangerous?

It’s always dangerous to look at the sun with the naked eye. A blast of focused light from the sun can damage the photoreceptors in your eyes, which can lead to vision impairment or blindness.

An eclipse is an especially risky time to look directly at the sun, Suzanne Fleiszig, a professor of optometry and vision science at Berkeley’s School of Optometry, previously told The Washington Post. While the sun is partially obscured, some wavelengths that trigger pain are blocked, dulling the reflex to look away. But enough rays will still get through to damage your eyes.

Even just a quick glance at the sun can leave your eyes vulnerable to damage. It’s also not safe to look at the sun through a camera, telescope or binoculars, either, the American Astronomical Society warns.

I looked at the eclipse without glasses — what do I do?

If you looked at the solar eclipse without protection, or with faulty glasses, you should pay attention to symptoms like pain or blurred vision. If your vision is blurry, or you see gray spots that don’t go away, you may have suffered damage to your retinas, said Seth Laster, an optometrist in Fort Smith, Ark.

“I tell people, ‘Hey, if you’re looking at something [and] a part of the image is missing, definitely come in and see your local optometrist,’” Laster said.

Solar retinopathy — damage to your retinas from looking at bright lights like the sun or a laser pointer — doesn’t always cause pain but can permanently affect on your vision, Laster said. Experts added that the damage isn’t always evident right away and can emerge a few hours or days after looking at the sun.

“Viewing the sun is often like getting a sunburn,” said Tamara Oechslin, an optometrist and associate professor at the University of Alabama at Birmingham. “You don’t notice the worst of the damage until an hour or two later.”

Eye pain can also be caused by photokeratitis, which is caused by exposure to ultraviolet rays. It’s also known as snow blindness or welder’s flash when it’s caused by sunlight reflecting off snow in arctic conditions or the light from a welder’s torch. Photokeratitis is a more painful condition than solar retinopathy, Jacobsen said. But it’s less likely to occur when viewing an eclipse, and usually doesn’t lead to permanent damage.

The main factor to consider is how long your symptoms last, Jacobsen said. If problems persist after using eyedrops, or if blurry shapes in your vision continue when you close your eyes, it’s probably best to see your doctor.

“There’s so many different things that can happen with people’s eyes,” Jacobsen said. “And we can never go wrong by saying, ‘Call your eye doctor right away.’”

Caroline O’Donovan, Amudalat Ajasa and Joel Achenbach contributed to this report.