for those who have enough discomfort to make using a computer mouse difficult, I have a program which *I* use now & then - which does not require you to click the mouse. (PC only, I'm afraid)

You simply move the mouse and pause its arrow where you wish, and it clicks for you. There are various setting for the time delay, for double clicks...etc.

The program has become a pay program and changed its name from "Mouse Tool" to "Quill Nib"..or just "Nib" at http://www.aerobicmouse.com/software-overview/
(they have special hardware, as well as software)

but the original free program can be found at this site as "MTool31.zip". It works very well..