tom, <br>this anti scrach coating on your glasses, how afective is it? <br>my glasses are geting scrached all the time and I get really pissed off with it. did it cost a lot? <br><impact rated> whats that? sounds like it might be good idea mine have taken some knocks and it would be nice to know there not going to fall apart at the worst time, a carry a small srewdirver for them allways. But they could get well beyond a lose screw. <br>-james