Recently stumbled into this excellent programming related article on how to make iOS apps handicapped “accessible.” 

If you’re interested in programming for the iOS, you should read it. What’s interesting to note for everyone else though is this point – how easy it is for visually impaired people to use iOS (iPhone, iPad) devices, how much of that support is just simply “there” courtesy of the standard Apple interface toolkit, and how easy it is to make that support complete for many utility apps.

A number of the biggest iPhone/iPad fans I know of are visually impaired.