What Happens If You Look at a Solar Eclipse Without Glasses?

If you look directly at the solar eclipse on Monday without protection, you could damage your eyesight — permanently. 

“Viewing any part of the bright sun through a camera lens, binoculars, or a telescope without a special-purpose solar filter secured over the front of the optics will instantly cause severe eye injury,” NASA says. 

"Even a few seconds of viewing the sun during an eclipse can temporarily or permanently burn the macula," which is part of the retina, the Journal of the American Medical Association says. "Once retina tissue is destroyed, it cannot regenerate, resulting in permanent central vision loss."

And the eye damage might not be immediately noticeable. 

"It's not really even obvious on an exam at first for those patients," said Derek Price, an optometrist in Fort Wayne, Indiana, told NBC. "They'll come in with a complaint, they'll tell you I'm seeing a spot in my vision and that's all you get. But then over the course of the next couple months, if they come back, then you can see where it's degraded the retina itself. If it's degraded... the photoreceptors in the back of the eye could be lost forever."

As NASA explains, “When a person looks repeatedly or for a long time at the sun without proper protection for the eyes, this photochemical retinal damage may be accompanied by a thermal injury —  the high level of visible and near-infrared radiation causes heating that literally cooks the exposed tissue.” 

“This thermal injury or photocoagulation destroys the rods and cones, creating a small blind area. The danger to vision is significant because photic retinal injuries occur without any feeling of pain (there are no pain receptors in the retina), and the visual effects do not occur for at least several hours after the damage is done “

The only way to safely look at the eclipse is through solar eclipse glasses, which specialized eyewear recommended by NASA. They are specifically made out of materials that enable safe sun viewing.

"Solar eclipse glasses use lenses that are made of black polymer, a flexible resin infused with carbon particles," according to the Planetary Society's website. "They are about 100,000 times darker than ordinary sunglasses and block nearly all visible light as well as all infrared and ultraviolet light."

Eclipse glasses aren't the only form of protective eyewear onlookers are suggested to use. Handheld solar viewers are another option if you can't get a pair of glasses.

NASA states that it "does not approve any particular brand of solar viewers." (The American Astronomy Society does have a list of reputable vendors on their own site.) However, NASA emphasizes that people hoping to look right at the sun must be wearing a pair, as regular shades "are not safe for viewing the sun" during the eclipse.