If you want to make things easier on the eyes - make sure the lighting around your screen is of a similar brightness as the screen itself. It can be a bit less, but what you don't want is a bright screen surrounded by darkness in your field of view. This lighting needs to be diffuse - indirect works well - and you don't want to have the bare bulb or any bright spots from the lighting anywhere in your field of view.
Your pupils will dilate to suit the average brightness - which makes the screen too bright for comfort.
Source: I spend HOURS on the computer every day - and this tip makes a HUGE difference (for me, at least).
(I have even put an LED strip around the back of my TV to light up the wall a bit for this reason.)