Well, you can damage eyesight due to gaming or watching TV if you are doing it incorrectly. Such as if you stare at a screen too long while all lights are off, it could damage the neural endings.
Well, I defy genetics, considering my entire family has some need for prescription glasses. I just use reading glasses to magnify the words, so I'm not having to stare too intensely. Even though I never use the glasses xD!