I personally get headaches when I read too long on anything backlit (desktop monitor, laptop screen, Droid, Blackberry). I do not get headaches from reading on my Sony PRS-350. But I have not tried adjusting color schemes on backlit devices to see if that helps (I'm a lazy person and that sounds like work
).
I also tend to read on backlit during the day (reading docs for work, surfing the net, etc) and usually wear contacts during that time period.
Me + contacts + reading on computer (or playing WoW for hours on end
) = sahara desert eyes