Anyway, Compiz Color Filter is designed for people with visual impairments precisely to improve contrast. It gives you a hot key using which you can switch around the colors either on a per-window basis or for the whole screen. It's instantaneous and has zero performance impact. It has multiple schemes through which you can cycle until you find the scheme that suits the web page in question. Or make your own.
I'm typing this in a scheme which converted HN to have white text on a bluish background color scheme.
It's frigging awesome. Check it out (or it's equivalent if one exists for Windows/Mac).
I don't think I have any vision problems. Do I? Does everybody else find the page I linked above easy to read?
[1] I'm unsure which project exactly should take credit, so I'm leaving it vague.