Check out this silicon iPhone case for the sight-impaired, via Core77:
Portugal-based designer Bruno Fosi has developed a prototype iPhone case that would enable the sight-impaired to use the device. The silicone case has debossed, tactile logos, icons and characters, yet is still thin enough for the screen to register touches. Used in conjunction with text-to-speech features, it opens up a world of possibilities for those without sight. Not to mention the blind could eke out some extra battery life by turning down the backlight.