To the Editor:

As Bang Wong notes in his recent column on proper color coding in figures, just picking suitable colors is not always sufficient1. In particular, one important, but often neglected, issue is color blindness because it affects a substantial portion of the human population (additional information is available at MedlinePlus: http://www.nlm.nih.gov/medlineplus/colorblindness.html). One well-known example of frequent color vision defects is red-green deficiency, which occurs, in case of Northern European ancestry, in about 8 percent of males and 0.5 percent of females2. Therefore, it is advisable to select figure colors accordingly, and journals might introduce color guidelines to increase the authors' awareness of this accessibility issue. For instance, software such as Adobe Photoshop offers color blindness proofing filters that simulate what an image will look like to individuals with color blindness. Authors can then adjust the image to make it universally accessible (see Adobe Photoshop CS5 accessibility overview at http://www.adobe.com/accessibility/products/photoshop/overview.html).