It’s a dark reddish orange, the back of the eyeball, when you see it through the pupil.  Except for the ivory-colored optic nerve in the middle, taking sights back one after another, and the blood vessels spidering out from its center across the retina. Nowhere else in the intact body can you see bare arteries pumping up close. You look in there, in the case of somebody in a coma, to see if the nerve is swollen from brain pressure. But before you do, you check the pupil, the round black silent window over which even a conscious person has no control. It tells you by its response to your narrow beam, about where pressure might be starting and how much time is left. It reacts even when the person can’t. So tightly do we hold to light.

In Medical Humanities 35, 2, 2009.