The fitted univariant fluence–response curves of percent control-adjusted melatonin suppression for nine monochromatic wavelengths of visible light. Each fluence–response curve is derived from eight healthy volunteers who participated in a complete, within-subjects experimental design. In each graph, the data points represent group means. Each curve has a high coefficient of correlation. This data shown here elucidated a novel sensory system in the human eye and have been instrumental in developing new lighting technologies and lighting methodologies for light therapy and human health.