If you, like our nation’s president, looked directly into Monday’s eclipse, you might wonder: Did I just damage my eyes?

Whether by accident or disregard, untold masses looked at the sun with unshielded eyes during the must-see-safely event. By Monday afternoon, people were already freaking out about their eyes online.

The sun isn’t more damaging to your eyes during a solar eclipse than on any other day. But as Ohio optometrist Michael Schecter told USA TODAY, the moon’s covering makes it a lot less painful to look at it for a lot longer. That makes it tempting for folks to peer over their cardboard eclipse glasses to see “what’s really going on,” Schecter said.

So how long can you look before getting hurt? Not long, says Jacob Chung, Chief of Ophthalmology at New Jersey’s Englewood Hospital.

“If you look at it for a second or two, nothing will happen,” he said. “Five seconds, I’m not sure, but 10 seconds is probably too long, and 20 seconds is definitely too long.”

You won’t feel any pain if your eyes suffer damage, Chung said, because our retinas lack pain fibers. Retinas can’t heal themselves, either, he said, making permanent damage a possibility.

Any blurry vision won’t kick in for a day or two, after the affected area swells “like an egg yolk” Schecter said. It can take months, even a year, for eyes to return to normal, he said — if it they do at all.

“You would basically get a burn on your central vision,” Schecter said.

According to an article on lifescience.com:

“Dr. Nathan Podoll, a spokesperson for the American Academy of Ophthalmology, agreed that eye damage after observing an eclipse would not typically show up as pain or discomfort in your eyes. Instead, people with solar retinopathy have visual symptoms. These symptoms include blurriness or blind spots in your vision, or a dark or dim spot in your central vision, Podoll said. People may notice these symptoms within 4 to 6 hours of the viewing event, Podoll said, or the symptoms could appear the next day. … Experts say that if your eyes felt a little strange after the eclipse, it’s not necessarily a reason to worry. That’s because this funny feeling is not a sign of “solar retinopathy,” or damage to the eye’s retina that can occur from looking at the sun. It could just be a case of  dryness on their eyes’ outer surface from holding one’s eyes open too long — a condition known as exposure keratitis.”

A 2001 study looked at 45 British patients who viewed the 1999 solar eclipse. While 20 patients claimed symptoms of affected vision, just five showed damage on their retinas. All five looked at the eclipse for 18 seconds or longer, Slate’s Will Oremus noted.

One way to test at home whether you’ve damaged your eyes is to print off an Amsler Grid, Schecter said, a tool used to detect vision problems. Closing each eye separately, focus on the center dot and see whether the surrounding grid appears wavy, splotchy or distorted, he said.

According to an article at businessinsider.com: “If you are experiencing vision changes or eye pain, even if you wore proper eye protection, call an eye doctor to schedule an appointment. Many cases resolve themselves over time, within a day or even over a couple of weeks, according to an editorial in the journal JAMA Ophthalmology. But if vision hasn’t come back within six months, it’s not likely to — and there is, unfortunately, no treatment for solar retinopathy.”

Josh Hafner, USA TODAY