Regulation of our sleep-wake cycle is crucial to health and well-being. The quality (intensity and spectral distribution) of artificial light is currently described according to its ability to activate rod and cone photoreceptors in the human eye. This approach ignores the discovery of a third photoreceptor that Lucas and his group have shown to be responsible for a range of sub-conscious neurophysiological and neurobehavioural responses to light, which together strongly contribute to health, productivity and well-being. Their research has established ways of measuring light that predict its effect on these newly discovered photoreceptors. They have partnered with industrial and public policy (various) organisations to translate this knowledge into improved artificial light sources and updated international standards for architectural lighting, for use in a wide range of domestic, public and industrial settings.