(Pablo Blazquez Dominguez / Stringer)
As you may have heard, a total solar eclipse is making its way across the continental US on Monday.
You need to wear protective solar-eclipse glasses to safely watch the moon cross in front of the sun, as the sun's powerful rays can cause serious eye damage if viewed directly. (There are several good ways to watch the event without staring at the sun if you haven't been able to find glasses.)
But one method of trying to watch without directly looking should be avoided, according to Dr. Tongalp Tezel, an expert on retinas, at Columbia University Medical Center.
Don't try to watch the eclipse through the front-facing selfie camera on your phone, Tezel said in a news release.
You can take photos of the eclipse with your phone camera without damaging the sensor, as long as you don't have a zoom lens attached — there's no danger to the camera itself.
But your phone screen can reflect ultraviolet light back into your eye, according to Tezel, potentially causing the same damage — solar retinopathy — as looking at the sun itself. Even taking a selfie without wearing eclipse glasses could reflect the sun's light back into your eyes.
"Many people will think it's safe to take a selfie with the eclipse in the background because they aren't looking directly at the sun," Tezel said. "What they may not realize is that the screen of your phone reflects the ultraviolet rays emitted during an eclipse directly toward your eye, which can result in a solar burn."
According to NASA, symptoms of sun damage usually include blurred vision, seeing dark or yellow spots, pain, or losing vision in the center of the eye. That can make it hard or impossible to read or to focus on whatever is in the center of your view.
Some people's vision recovers within a day — but there could still be damage to the eye, which could result in later problems. In general, people recover as much vision as they ever will within six months of the event, according to the American Academy of Ophthalmology.
If you are within the 70-mile-wide band of totality, you can safely remove your protective glasses once the sun is covered. You'll know it's time because you won't be able to see anything with those glasses on. But as soon as beads of light start to reappear, it's time to protect your eyes again. Even 1% of the sun is enough to cause damage.
If you can't find eclipse glasses, we'd recommend making a simple pinhole camera to watch safely.
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