THE CLAIM -- Sitting too close to the television is bad for your eyes.

THE FACTS -- It was more than 70 years ago that television sets first went on sale in the United States, and perhaps it was just as long ago that a cautious mother, noticing a son or daughter propped in front of that mesmerizing new invention, snapped and barked the words that generations of children would grow up hearing: "Don't sit so close; you'll ruin your eyesight!"

Now, scientists can say with certainty that the age-old warning is outdated.

Before the 1950's, television sets emitted levels of radiation that after repeated and extended exposure could have heightened the risk of eye problems in some people, said Dr. Norman Saffra, the chairman of ophthalmology at Maimonides Medical Center in Brooklyn.

But modern televisions are built with proper shielding, so radiation is no longer an issue. "It's not an old wives' tale; it's an old technology tale," Dr. Saffra said. "Based on the world our grandmothers lived and grew up in, it was an appropriate recommendation."

While concentrating on a screen for hours on end may not cause blindness, it can lead to eyestrain. Keeping the room fairly well lighted while the television is on and peeling your eyes from the screen for an occasional break can prevent this.