Testing solar eclipse viewing glasses in CSA's Redmond lab covers three categories: the amount of light that can pass through the glasses; how uniform the protection is (meaning, are there any holes that allow extra light in?); and finally, coverage.
There is no regulatory agency for solar eclipse glasses, so companies can advertise safety without proving it.
"The hazards of viewing the solar eclipse without glasses or proper glasses is retinal burning or physically burning the back of the retina at the back of the eye. When you view the sun, the way the human eye works, it actually focuses that light down a thousand times. If you think the sun is bright, if you're viewing without glasses, you're putting a thousand times more light in your retina when you focus on the sun," explained lab manager Aaron Miller.
None of the glasses tested got a perfect score.
"Nearly all of them fail in one way or another, but none fail at actual viewing. So it's usually a face coverage issue or perhaps they're too dark to view a solar eclipse, darker than what the standard recommends," Miller said.
Even with protective glasses, experts say it's never safe for children to look directly at the sun.
"CSA found that all the single use glasses they tested failed in some way. However most failed because they did not let enough visible light through, which would mean that your view of the sun may be dim. All the glasses tested below however did stop harmful UV and IR light in the CSA laboratory. One warning which CSA gave us, is that just because the glasses they tested block UV and IR rays, it doesn’t mean the pair you have at home is safe. Any damage to the glasses lens or manufacturing defect can lead to an unsafe pair of glasses. The safest option is that if your glasses aren’t listed on the NASA reputable vendor website don’t use them. In no event should you use the glasses for more than two hours. Any longer exposure can damage your eyes. Young children should view the eclipse through a pinhole camera, which can be easily constructed at home. Most eye injuries reported after a solar eclipse occur in young children and teenagers. Even a sliver of the sun can damage your eyes," wrote David Bajorins in a statement to KING 5.