I read on-line, too, but have a problem similar to Mobius'. I don't get headaches, but my eyes dry out and hurt. I'm more than arm's length from the screen, my set-up is ergonomically correct, my lambda is way down (I hope that's the right word -- I mean the screen is relatively dim and the contrast is at maximum). To alleviate the problem, I have all the lights in the room turned on and I'm wearing polarized UVA/UVB sunglasses. It helps, but I've still got to remember to blink a lot.