The Pupil Isn’t Anything

Many people often say that the pupil is the small black dot in the middle of the colored part of the eye. Some people have big black dots and some have little black dots, and they can change size. What is actually happening when the pupil changes size is that the iris (the colored part) is changing shape around it. The black area in the middle is actually just a hole! The hole is, of course, a crucial aperture to let light into the back of the eye. That is why the iris changes shape to make the pupil bigger in times of low light. However much we talk about big pupils and small pupils, if you actually went to try and touch a pupil (for example during eye surgery), there would be nothing to touch. “Pupil” is just our name for the space in the center of the “doughnut” of the iris.