Temporarily try something different under the mouse & see if it comes good. Some patterns on mousemats can confuse optical mice, yes. The illumination is from a Light Emitting Diode (LED), so no laser. Motion is sensed by detecting the movement of the position of a pattern read from the surface by a basic image sensor (CCD), some mousemats prevent this from working reliably. I've had a couple where the position jerks & jumps if I use an optical mouse.
Edited by Platypus, 02 November 2007 - 08:25 PM.