This is a picture of an eye:

credit for picture: javascript:eye1( )

Link to more pictures:http://www.nei.nih.gov/eyediag.htm


Above: This is an animation that shows our experiment. It has a camera on the left end of the board and each object at four, six, eight, and ten feet. When the board moves it does not mean it is going to a different depth, it signifies that the object has changed.