i kind to have thought of this long time ago. surely we all know about braille book right? anybody with perfect eye can read braille? (i mean read with hand, not eye). imo, if we lose one sense, our concentration on another will gain higher (such as skin sense, ear etc) once i was in a lift with braille button (in hospital iirc), i tried to close my eyes and touch it to figure out the shape, i just cant. i always tend to open and see it with my eyes. there is a quote from a movie... "your eyes can fool you" but your brain cant.