[ProDigit]

There actually is a trick on reading in an optimized environment. I can't believe it but I once read a book written in the late '80's,beginning '90's that held this info (as well as a lot of scientific data and results and much research), costed +$80.
But even back then they already knew if you're going to work with computer screens,the trick is to view over your screen to the background.
Then adjust the brightness/contrast in such a way that the screen seems to blend in with the background (often on laptops used in normal environments that would mean set the brightness nearly to minimum).
Once the screen has about the same amount of knits or light intensity of your background, boost it with 5 or 10% brightness.
That is the perfect setting for reduced eyestrain.

A too high brightness will oversaturate and tire the eyes.
A too low set brightness will cause your eyes continuously to be distracted by the background which appears lighter than the screen. Also, a too low contrast ratio could result in a more reflective image on the screen, and the eyes might get strained more due to glare (seeing light being reflected on a reflective LCD screen).

So the screen needs to be set brighter than the environment to 'call' the attention of your eyes (they will more naturally travel to the screen instead to the environment), but it can not be set too bright for that causes the eye strain.

So a lot of people complain about eyestrain on LCD's just because they don't know how to adjust the screen to the right brightness!
A white field on an LCD screen on a good set brightness setting, should not appear much brighter than a white paper or an ebook reader.

Same goes for E-ink. Reading your E-ink device actually hurts in full sunlight, and your eyes get damaged doing so!
E-ink is about the perfect screen for reading in the shadows and inside under mild light (as well as Pixel Qi's technology).