Television rays, even from color televisions, have not been shown to be a form of ionizing radiation, so television watching should not be harmful, not even stting close to a television set for long periods. The only danger would be to your back if you tend to sit slumped for hours on a sofa in front of the set.  You would be best advised to sit on a firm chair, so your back is supported, with your feet up on a low stool, to maximize circulation and ease potential lower back problems.