Remember when they used to tell you not to sit too close to the TV screen? I’m typing this on a screen that’s about 18 inches from my face. But it’s OK because it’s not a TV screen, it’s a computer monitor, which makes a huge difference because .... OK there isn’t any difference at all ... it’s the exact same thing. It’s just that the same people who were telling you not to sit too close to the screen as you grew up are now sending you videos of cats who can flush toilets and a guy who plays Beethoven’s Fifth Symphony on a ukulele. If you watched this stuff on a TV, you’d be wrecking your eyes and wasting time, but since it’s on a computer, it’s science.