Unless it has been diagnosed as carpel tunnel syndrome, I would guess that the wrist pain is actually a more general "repetitive stress injury" (RSI). Proper posture helps a lot for this, as does taking regular mini-breaks to let your wrists rest. Software RSI break timers help; I use AntiRSI on my mac. The idea is to let your arms hang down for 10 seconds or so every 5-10 minutes. Take longer breaks regularly, and stretch your wrists, arms and shoulders.

Google 'RSI wrist stretches' (or exercises), etc. The book "It's not Carpal Tunnel Syndrome! RSI Theory & Therapy for Computer Professionals" is highly praised, but I haven't read it personally.

I've found that a trackball is much easier on my wrist when I'm forced to do any mousing. The Microsoft Natural Ergonomic Keyboard 4000 helped too, but I couldn't stand the space bar's noise and action -- it's worth looking into a more friendly keyboard anyway.

Edit: As for eye strain, try to focus on something in the distance while you're letting your wrists rest. Human eyes aren't particularly well suited for focusing close-up for long periods of time, so you should let them relax once in a while.