Guess I should consider myself lucky that I'm left handed.  I keep all kinds of things in my hand, but it's not very close to the screen.  I have adapted to many things in a right handed world without much thought, but using scissors isn't one of them :-)  I don't know what difference left handed scissors make - there aren't many of them, and 99% of mine aren't. I never thought about why I didn't seem to ever scratch the screen - score on for the lefties of this world!