Monday's historic solar eclipse was a wonderful gift, a chance to experience something real, to come together with friends and strangers, to bask in our mortal humility. Hopefully you took it all in under the safety of special eclipse-viewing glasses, but if you did what the President did, and stared directly at the damn thing, you may be wondering if today is your last day of perfect vision.

NPR turned to optometry expert Ralph Chou, who noted that it "takes at least 12 hours before we can tell if anything has happened," though it could take days. Chou added that "if people just saw the sun briefly without a protective filter — just a fraction of a second — the chances they've hurt themselves are very low." Most reports say looking at the eclipse for a split-second may be fine, but 10 to 20 seconds is pushing it.

Jacob Chung, Chief of Ophthalmology at New Jersey's Englewood Hospital, told USA Today, "You won't feel any pain if your eyes suffer damage," and optometrist Michael Schecter noted that the damage won't be noticeable until the area "swells 'like an egg yolk'."

According to PreventBlindness.com, "eclipse blindness, or retinal burns, [is] also known as solar retinopathy. This exposure to the light can cause damage or even destroy cells in the retina (the back of the eye) that transmit what you see to the brain. This damage can be temporary or permanent and occurs with no pain. It can take a few hours to a few days after viewing the solar eclipse to realize the damage that has occurred."

So if you damaged your eyes—like this guy did in 1962—sometime this week you'd be experiencing blurred vision, loss of vision in the center, color distortion, afterimages, or blindspots. If that happens, you need to get to an eye doctor to see if you damaged your retina.