Next week, on August 21st, millions of Americans will be able to view a total solar eclipse as it passes over the nation from Oregon to South Carolina. The last time we were treated to an eclipse of this magnitude was way back in 1979. But you can’t just walk outside and look up to the sky; if you plan on watching the eclipse next week, you’ll need a special pair of glasses. Here’s why.
Think about a normal, hot, sunny day. If you glance up at the sky, you’ll be forced to look away because your eyes are sensitive to the sun’s light. When a solar eclipse occurs, the light from the sun is momentarily blocked, but the harmful UV rays keep on coming. So even though you’ll be able to gaze toward the sun during an eclipse, you can still do serious damage to your eyes.
Exposure to the sun’s UV radiation can cause photokeratitis, or sunburn of the eye, especially during an eclipse when there’s no sunlight to make you blink or look away. Photokeratitis can cause eye redness, burning and the sensation that something gritty is stuck in your eye. In extreme cases, prolonged UV exposure can do permanent damage to your retinas.
If you’re shopping for eclipse glasses, you should look for special-purpose ISO-certified solar filters. They’ll be branded as “eclipse glasses,” or “handheld solar viewers.” The glasses will protect your eyes from harmful UV radiation during the eclipse, and allow you to safely enjoy the spectacle.
Thanks to a partnership with the Space Science Institute, public libraries throughout the country are distributing these eclipse glasses to interested astronomy enthusiasts for free! You can also find them at some retailers, but make sure they’re the authentic ISO-certified filters before you buy. Check with your local library to see if you can get your pair of free eclipse glasses today!