When I was growing up (well, to the extent that I ever did...
), my parents always insisted that we stay at least five feet from the TV screen, because it was "dangerous" (the X-ray thing) and "would wreck our eyes". Not sure about the X-ray issue (although if you think about how X-ray tubes work, it is a VERY reasonable possibility that TV tubes could emit some of those frequencies, too), I think they were right about the latter, for sure, judging from how computer screens at close range tire the eyes!