Although you’re aware of the light that you see, light also affects us in ways that you might not appreciate. These so called “non-image forming” (NIF) pathways were recently discovered, they start in the human eye before projecting to over a dozen brain regions. They modulate aspects of human function including our daily rhythms, our sleep patterns, the way we feel and the way we think. Thus, light is fundamentally entwined with optimal brain function. In the laboratory, we can tightly control and characterize light at the source of this pathway, but what is less understood is how this affects our various behaviours. Working with experts at EPFL, I will evaluate how systematic alterations to the color and intensity of lights alters the most readily accessible NIF output pathway, the pupil’s response. With this data we will build a model that characterizes the pupil’s response to any light and use it to predict how NIF sensing would differ in people with different types of disease. This information will be used in future clinical studies at Stanford University to optimize light stimuli to target the various NIF pathways, including for sleep and circadian rhythms. Such knowledge is important where with modern lighting, we can design home, school and workplace environments that can maximize both productivity and wellbeing.