Although the Xerox optical mouse was standard equipment with the 6085 in 1985, I do remember seeing an optical mouse being used with the 8010 during a demonstration in 1982. Perhaps this was a demonstration of the prototypes? The experimental versions were being built in 1981. See some great illustrations and background:
Lyon, Richard F. The Optical Mouse, and an Architectural Methodology for Smart Digital Sensors. VLSI·81-1 AUGUST 1981. @ Xerox Corporation 1981.
http://www.bitsavers.org/pdf/xerox/parc/techReports/VLSI-81-1_The_Optical_Mouse.pdf
I should have known there was a white-paper on the Lyon's mouse. Lyon was mostly working on chip-design methodology with Carver Mead (Introduction to VLSI Design, it was hot back in the day), and the mouse was kind of a worthwhile demo of that. We had a captive N-MOS fab and it was fairly easy for us to do multi-project chips and get custom VLSI in a run of about 10 bonded out chips or so per project for cheap.
I had the distinct pleasure of working for Tibor Fisli for a while. He and Gary Starkweather are the inventors of the laser printer, Tibor did the optics and Gary did the electronics and dragooned a couple of people for software. I distinctly remember Hal Murray (who did a *lot* of early router software) being involved. Their first model was about the size of a smart-car and would deliver 2 pages of black and white per second all day long. Big fun.
I, for one, welcome our new Cybernetic Overlords /.