Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 1Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 2Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 3Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 4Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 5Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 6Running blind: How Simon Wheatcroft uses his iPhone to see   - photo 7