There is no doubt about the complexity of the eye. It is an amazing organ, able to detect objects from many miles away. The eye can tell us about colors, about movement and about distance. It gives us immediate information about where to go and what's coming at us, as well as an understanding of the environment around us in a much more accurate way than our ears can. No wonder there are so many fascinating things to know about it, and these are just 50 of them...