Always have had an little drift with my Tobii, nothing to big just maybe 1-2 cm on screen to what I have been looking at.
But… A couple of weeks ago i got my eyes checked and it was obvious that i needed glasses (for the optician, I thought I had ok vision, surely a little degraded but, OK). Got the glasses yesterday. Guess what, the accuracy improved when wearing my new glasses.
Thought i would share this experience if someone out there have a small drift, as I did.
Conclussion= Tobii didn`t malfunction, I DID.