Not that bad for your eyes. As long as you feel comfortable and can see
everything you need to (i.e. paperwork as well as the computer) is the
main thing. Many people have the brightness of their monitor turned up
too bright - try turning the brightness down a bit... it will seem too
dim at first but you'll soon get used to it. Also, it's generally best
if you're looking slightly down to the monitor rather than looking up at
it. And take breaks, look away as often as you can.
Dom