Hi Reddit, my name is King-Wai Yau, and I’m a neuroscientist at the Johns Hopkins University School of Medicine studying sight and smell! I started out in medical school at the University of Hong Kong but soon switched back to basic science and came to study in the U.S I have been studying vision for over 40 years, focusing on its first step, in which light interacts with the rod and cone receptor cells of the retina, initiating a complex biochemical/biophysical process which your brain eventually interprets as vision. However, we now know that additional photoreceptor cells beyond the rods and cones you learn in school actually exist in the retina. These newly found cells mediate eye functions unrelated to creating images, like constricting your pupil in response to changes in light. These non-rod/non-cone photoreceptors are important for helping us appreciate the progress of the day and, for example, in enabling us to get over jet-lag when traveling across time zones. Recently, my research has focused on understanding how light-induced pupillary constriction in mouse eyes can occur without the brain. Unlike in humans, mice’s pupils can constrict without an obligatory connection to the brain because light-detecting pigment, present in the iris’ sphincter muscle, responds directly to light. These findings shed light on the evolutionary path of the pupillary light reflex in vertebrates, which is essential for regulating light entry into the eye especially under bright conditions. Outside of the lab, although I hardly watch any commercial television, I would compulsively put aside work in the evening to watch Nature and Nova programs when they come up on Public Television. Any knowledge about biology, physics and chemistry is fair game to me! Check out my latest research here I’ll be back at 1pm ET today to answer your questions.