(Anderson Cooper/Instagram)

Yes, you can burn your eyeballs -- or more accurately, your corneas.

That's apparently what happened to CNN's Anderson Cooper, who talked about it on TV this week. He says he spent two hours on a boat in Portugal without sunglasses, and ended up "blind for 36 hours."

"It turns out I have sunburned my eyeballs," he said on Anderson Live. "I had no idea you could do this."

Doctors say Cooper had a case of photokeratitis -- which skiers know as snow blindness. It happens when intense ultraviolet (UV) light, often reflected off water, sand or snow, burns the cornea, the transparent tissue covering the front of the eye.

"I see it in people out all day at the Jersey Shore," says Anne Sumers, an ophthalmologist in Ridgeway, N.J., and a spokesperson for the American Academy of Ophthalmology.

The condition does not cause blindness, but "it's so painful that people feel they can't open their eyes," she says. Other symptoms can include a feeling of grit in the eyes and blurred vision, says Fraser Horn, an associate dean at the Pacific University College of Optometry in Forest Grove, Ore. Effects are temporary, much like a sunburn of your skin.

Sumers says she tells patients to "take it easy in a dark room" for a day or so. She doesn't advise wearing an eye patch -- which Cooper sported in a Twitter picture he circulated.

Most people recover in "two or three days, tops," Horn says. "The cornea is very fast-healing."

But you can avoid the pain, and lower long-term risks for cataracts and skin cancer, by wearing sunglasses that block at least 99 percent of UV light (UVA and UVB) and broad-brimmed hats, even when the sun doesn't seem very bright, experts say.

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