Degunking and delinting the rollers for the mouse balls was a daily preventive maintainance routine for the Macintosh computer rooms we operated on campus in the 80's.<p>The MS-Dos PC rooms had no mice yet. There we had to turn off the machines in the morning as praksters loved to set the whole room looping explicit ascii imagery on the greenscreens over night.
This might explain why early optical mice used a grid patterned mouse pad. I had one from Mouse Systems and the mouse pad it came with was a metal plate printed with a fine grid pattern.
"The first rolling-ball mouse"
<a href="https://www.e-basteln.de/computing/rollkugel/rollkugel/" rel="nofollow">https://www.e-basteln.de/computing/rollkugel/rollkugel/</a><p>So 13 years from balls to optical.
Slightly related: I still use a Microsoft Wheel Mouse Optical (WMO) 1.1a, from the early 2000s. It's become a bit of a cult-classic in the online-FPS scene, due to being a real game changer for Quake and Counter-Strike players when it was released. I still love its shape, and the 2000s aesthetic.