DVD's on your PS2

Do DVD's actually damage your systems lens? and on the old models of the PS2 is it bad to play those blue disc PS2 gams and PS1 games? My FFVIII started spazzing a bit on my ps2 and i never scratched that game or anything and the disc in great condition I have heard rumors of this and I do not know if its true.

Please post! thanks

Ive had a modded PS2 for a long time, and I've used every form of media, and I have had no problems as of yet...

Only PS2 problem I had is when my PS2 overheated, so keep the fan clean, and keep it on a hard flat surface.