I want to mention a little program I saw mentioned in the Reader's Digest, and tried last night.  It is called f.lux (you can google to find the website; I don't remember it off-hand).  And what it does is change the tint of your computer screen from blue spectrum to more amber colored.
 
It also has the effect of making the screen seem less glaringly bright.  During the day, I don't notice my screen being either blue or too bright; but at night, I am always feeling like it glares and I can't get it dim enough to look at comfortably.  But this handy little program fixed both of those problems for me.  :D  It leaves your screen normally colored during the day, it says, and changes the tint as it gets dark (judging when that is by where you live).

And it's free.  :)