This image shows a dissected cow eye. The vitreous humor has been removed and the retina is visible a thin layer of tissue covering the shiny blue tapetum. In cows, the tapetum is reflective and helps the animal see in the dark. (This is also why cow eyes appear blue in the flash of a camera.) The lens is visible as a spherical object, in preserved specimens it is not clear. The iris has been removed, it is normally a dark brown or black, the opening in the center of the iris is the pupil.