I started having tendinitis in my right wrist in 1997. I was 19, and had been programming for about 7 years. The tendinitis was due to the use of a regular mouse.
Ever since, I have only been using trackballs. I also switched to pointing with my left side instead, even though I am left handed. I have been using various versions of Kensington's excellent Expert Mouse .
In spring 2008, I built a home theater PC. The couch is located about 14 ft from the projection screen, and 11 ft from the PC. One year later, I have been unable to locate a decent wireless trackball for use with it. Especially one that can be used with the left hand. Some brands only design their wireless trackball to work with the shape of the right hand, which upsets me to no end.
If you have became aware of a good wireless trackball product that can be used with the left hand , I would like to hear about it.