Two interesting examples of interaction design targeted at blind people: This virtual mapping project by greek researchers (lead by Konstantinos Moustakas) allows to "convert video into virtual, touchable maps for the blind. The three-dimensional maps use force fields to represent walls and roads so the visually impaired can better understand the layout of buildings and cities". The good thing is that this virtual touchable maps work with standard video cameras.

And Demor is a location based 3D audio shooting game that is equally enjoyable for both blind as sighted players (Via Mr. Sterling):

"Players can physically move through the auditory surroundings and hear the different sound objects in their relative positions around them. These sound objects include environmental elements like the sound of a creek or the songs of birds. As the player moves through the game these environmental sounds remain in their geographical place and can function as navigational aids. (...) To play the game, the player is equipped with a backpack containing a laptop, a GPS receiver, a head tracker, headphones and a modified joystick. By using both locative and directional sensors the software can continuously update de spatial audio feedback to accurately reflect the user's position and direction in the virtual space, creating a kind of auditory virtual reality. "

Why do I blog this? I am not into this kind of research but these technology seems to offer relevant opportunities to solve problem with a good innovative angle.