Have you tried eye drops to moisturize?
Check out the highest rated review from here:
The reviewer compares 7 different eye drops.
>I have a long history of damage from repetitive strain injuries
This one got the highest score for ease of use:
>VIALS – EASE OF USE
>Bausch & Lomb: 6/5 extra credit for a completely unique, easy to squeeze design, it really stands above the rest
I don’t know if it applies to both the preservative and non preservative version.
Whenever you take a break from eye-tracking, a less-straining “click” that I’ve found is from a tablet:
Nexus 10.
Jump VNC app to remote.
Hacker’s Keyboard app for more keys.
AutoHotkey to remap buttons.
Use a wrist pronation motion (supination is the opposite) to tap the edge buttons of the tablet.