I have glasses which I use at work. The combination of crappy monitors and fluorescent lighting causes eyestrain :-( The glasses help a bit. I figure it has to be the lighting that's the key factor, since I used to use the same type of monitor at home and never had a problem there.
Just to be weird...my left eye is perfect, but my right eye produces a blurry image. I'd always assumed it wasn't focusing correctly, but it turns out that the optic nerve never developed, so while the eye itself works it produces a low-resolution image. I'm sitting about 18" away from a 21" monitor while I type this, and I cannot read what I'm writing if I only use my right eye. If I ever lose the use of my left eye, I'm screwed - can't read, can't drive...