Pupils are the dark-colored openings at the center of your eyes that let light in. Doctors can look at your pupils for clues about your health. The size of your pupils and how they react to light can ...

The colored part of the eye surrounding the pupil is called the iris. It automatically regulates the amount of light entering the eyes by regulating the size of the pupil. Light is the primary ...

You look in the mirror and notice that the dark circles in the middle of your eyes are bigger than usual. What's going on? Those dark circles are your pupils, the openings that let light enter your ...

The size of your pupils varies throughout the day, but most people’s pupils fall within a particular size range. We’ll look at when and why your pupils change size. First, the range of “normal” pupil ...

This article was originally on a blog post platform and may be missing photos, graphics or links. See About archive blog posts. For artists, drawing is thinking made visible. Pencil, crayon, chalk or ...