When playing my Super Nintendo and Playstation as a child one thing was for certain, I was on the floor a few feet from the bright TV screen. Even today if I am taking a game seriously that's the position I have to be in. The only thing that has changed over the years is my eyesight.
I can hear the echo of my mom now, "If you sit too close to the TV you'll hurt your eyes!" Just as her mom told her.
But is that true?
There is no evidence. In fact, it is believed kids have a better ability of focusing on things in closer proximity than adults. However, sitting too close to the TV may be a sign of nearsightedness. The child may need glasses and thats why they're sitting so close
If you do feel yourself straining your eyes to watch or read you may get a headache but thats it. The straining will not cause your eyes to become weaker.
So you can sit in front of the TV to your hearts content (or how long you can withstand the inevitable headache) In many cases believing in the myth isn't too bad as it can prevent unnecessary eye straining, head aches, and a way for parents to get their kids away from the television and outside.