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

That's apparently what happened to CNN newsman Anderson Cooper, who talked about the experienceonhis talk show Tuesday. He says he spent two hours on a boat in Portugalwithout sunglasses - and ended up "blind for 36 hours."

"I wakeup in the middle of the night and it feels like my eyes are on fire, myeyeballs, and I think oh maybe I have sand in my eyes or something. Idouse my eyes with water. Anyway, it turns out I have sunburned myeyeballs," he said on Anderson Live. "I had no idea you could do this."

STORY: Anderson Cooper: Blinded by the light

Doctorssay it's clear that Cooper had a case of photokeratitis - which skiersknow as snow blindness. It happens when intense ultraviolet (UV) light,often reflected off water, sand or snow, burns the cornea, thetransparent dome-shaped window covering the front of the eye. It's also ahazard in tanning booths. Welders get a version called arc eye.

"Isee it in people out all day at the Jersey Shore," says Anne Sumers, anophthalmologist in Ridgeway, N.J., and a spokesperson for the AmericanAcademy of Ophthalmology. It usually starts a few hours after peoplecome in from the sun, she says.

The condition does not actually cause blindness, but "it's so painful that people feel they can't open their eyes," she says.

Othersymptoms can include a feeling of grit in the eyes and vision that ismildly to severely blurred, s says Fraser Horn, associate dean foracademic programs at the Pacific University College of Optometry, ForestGrove, Oregon.

The effects are temporary, much like a sunburn ofyour skin. "The cornea is very similar to the top layer of our skin,"says New York dermatologist Deborah Sarnoff, senior vice president oftheSkin Cancer Foundation. "It does have the regenerative ability to come back and make new cells."

Sumerssays she gives patients eye drops and advises them to "take it easy in adark 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."

Butyou can avoid the pain -- and also lower your long-term risk fordeveloping cataracts and skin cancer on your eyelids -- by wearingsunglasses that block at least 99% of UV light (both UVA and UVB) andbroad-brimmed hats, even when the sun doesn't seem very bright, Sarnoffsays.

The American Optometric Association and The American Academy of Ophthalmology have additional tips on keeping your eyes safe in the sun.