Looking through glasses never damages your eyesight. In fact, it does the exact opposite. It will help to improve your vision only when you have them on. If you wear them because you have myopia (nearsightedness) then you might believe the myth that your eyesight worsens because of glasses, which, after numerous studies, has been found to be false.
Obviously not. Glasses just slightly bend the light before it enters your eye so it then focuses correctly for when you see it. If this did not happen you would see blurred images as your eye could not correctly focus it for you to see properly. If correctly it will prevent eye strain as your eyes will not have to work ridiculously hard to let you see clearly/
:S what the hell kind of question is that, if you were given glasses of course its not going to damage your eye sight :S
Only if you don't need glasses. But at least take them off before you go asleep.
Not nessicarly. It can improve your site too. Depends on your reason for having to wear them