When you need to distinguish something, don’t rely fully on color.  A great example is green for good and red for trouble, a common thing done for example on web server status pages.  Color blind users may have difficulty telling one from the other if the shape is the same.  Consider varying the shape as well as the color.

Inspiration: very simple and elegant — change the red dots to red squares.

via Design Patterns Solve Common Problems for Web Color Blind Users – Webmonkey.