“These lovely lamps, these windows of the soul,” the French poet Guillaume de Salluste Du Bartas wrote in 1578. He was, of course, referring to eyes. A decade later, “windows of mine eyes” was echoed by Shakespeare. These writers weren’t the first (nor the last) to note just how much our peepers can reveal.
We know now that many features of these sensory organs have evolved for vision. That’s why human eyes are largely similar to those of other primates. For example, we share black pupils that serve as openings for light.
