Anderson Cooper says a reporting assignment turned into a temporary blindness scare, The Associated Press reports. On his talk show Tuesday, Cooper said he was in Portugal last week working on a story for "60 Minutes" and spent two hours on the water. The newsman says that later, he developed a burning sensation in his eyes and lost sight for 36 hours. Cooper said he wanted to warn viewers about the risk. Dr. Nancy Snyderman, chief medical correspondent for NBC News, explained to Cooper he had suffered a retina burn.