I feel so lucky. I stare at the computer screen everyday for at least 5 hours a day and yet I still have perfect vision. And in the summer, double that. In fact, the last time I checked, I had 20/15 vision. Is there a reason for this? I'm very confused.
As far as I know, the "Sitting too close to the screen will ruin your eyes" as well as the "reading in bad light will damage your eyes" are myths made by parents (like "Do not go into the water after you have eaten", but I am not sure. Glasses here, got them 8 years ago, before I got my own computer or even my own tv, so not really because of screens.
The closest thing to those myths about screens ruining your sight is that you can get eyestrain if using for extended amount of times. But anything that requires such extreme use of your eyes can do that. I've done that while reading in a well lit environ for several hours.
