The extent to which most of us depend on vision for preventing falls can be experienced by closing our eyes, walking around, and seeing how long it is before we fall over something. The detection of objects, obstacles and changes in the walking surface is not, however, the only role that is played by vision when navigating our environment. As well as telling us what is in the world around us, vision, in conjunction with our other senses, also informs us of the whereabouts of our body in space.