How are your eyes doing? Do you take breaks from your computer frequently to rest them? Do you know what the factors are that can cause eye strain? This ergonomics site has some clear, direct information on computers and eye strain, including what to watch out for, how to set up your screen and other stuff I’ve never seen on eye care for those of us who are on screen or online all the time.
Particularly interesting is the section on conventional wisdom vs. current ergonomics which may teach you a thing or two and correct some old ideas about how to use a computer safely and set it up properly. It taught me quite a bit! I strongly recommend checking this site out.