Take it from Anderson Cooper: Always wear shades. Last week, Cooper, a CNN anchor, described an unusual experience that left him temporarily blind. On an overcast day, Cooper, sans sunglasses, was filming a news segment on the water off the coast of Portugal. That night, he woke up feeling "like my eyes are on fire."
"I douse my eyes with water," he said. "It turns out I have sunburned my eyeballs, and I go blind. I went blind for about 36 hours."
What Cooper experienced, ophthalmologists say, was probably photokeratitis, also known as ultraviolet keratitis. It is essentially sunburn of the surface epithelium of the cornea, said Dr Anne Sumers of Ridgewood Ophthalmology in New Jersey.
Most people wear sunglasses on a sunny day. But even on an overcast day, UV rays can pass through clouds and damage your eyes. And not just at the beach. Like sand and water, fresh snow can also reflect UV rays on a cloudy day.
One study in 2011 by the University of Utah found that out of 15 documented cases at an outdoor school, 13 were of people who had not worn sunglasses.
The other two occurred in people whose sunglasses lacked side shields. Four of the cases were in cloudy or low visibility conditions. Sumers said the condition is painful, but heals within a couple days with medication "and reassurance that permanent damage will not be done."
The verdict
Even on overcast days, UV rays can pierce through clouds and cause eye damage.
"I douse my eyes with water," he said. "It turns out I have sunburned my eyeballs, and I go blind. I went blind for about 36 hours."
What Cooper experienced, ophthalmologists say, was probably photokeratitis, also known as ultraviolet keratitis. It is essentially sunburn of the surface epithelium of the cornea, said Dr Anne Sumers of Ridgewood Ophthalmology in New Jersey.
Most people wear sunglasses on a sunny day. But even on an overcast day, UV rays can pass through clouds and damage your eyes. And not just at the beach. Like sand and water, fresh snow can also reflect UV rays on a cloudy day.
One study in 2011 by the University of Utah found that out of 15 documented cases at an outdoor school, 13 were of people who had not worn sunglasses.
The other two occurred in people whose sunglasses lacked side shields. Four of the cases were in cloudy or low visibility conditions. Sumers said the condition is painful, but heals within a couple days with medication "and reassurance that permanent damage will not be done."
The verdict
Even on overcast days, UV rays can pierce through clouds and cause eye damage.