Welcome to MobileRead, catsittingstill!
Glad you found us.
I don't have a TX, but I do have a Trēo, so I'm suspicious that there is a way to turn the backlight down on your TX -- I had a T3 before, and it could be turned down, but the control was pretty hidden. See if maybe this article
will do it for you.
If you're finding the backlighting to be bothersome to your eyes, then you are probably a good candidate for e-ink. When I moved to the Sony Reader last year, I never looked back to my Palm for reading, not even a little bit.