What is your monitor set to? Some monitors have all sorts of "temperature settings" for different light conditions. You could try switching between them. When I get serious about my Silent Hunter, I'll sit in a darkened room. Not total black-out, but just a lamp in the corner, away from a screen reflection, but enough that I can see the keyboard. Curtains closed if it's daylight out. That lets the "night shine" on my LCD monitor. Then, when the full moon is out, it practically blinds you...
Also, it doesn't take much with the gamma setting to notice a major difference.