In my job I have to view thousands of images everyday and I use ACDSee in fullscreen mode and the mouse scroll wheel to browse them. One of the mouse buttons uses a script to select the current image. Sometimes, when my finger gets too tired or hurts, I switch to my left hand and use pgup and pgdown to browse the galleries.
Do you know of any specific device that allows a more comfortable and ergonomic scrolling? I've thought of a dedicated and larger scroll wheel, but I don't know if such thing exists.
Recently I've discovered a kind of jog wheel called Shuttle Xpress, which is used for audio and video edition. I don't know if this would suit my needs. What do you think?