I've found that colors make a big difference in eye strain. I like a black backgound, and a burnt orange text. The white background really is hard on the eyes. You can set your editor , browser, and desktop colors... I view PM with a black background, burnt orange text, red/blue links. A black background tends to obscure moire patterns and flicker, and you can stare at it for hours with no strain. Use a big font too.