The first evidence for a novel type of photoreceptor in humans was published in the form of an action spectrum for melatonin suppression. This action spectrum has very different spectral sensitivities compared to rod and cone photoreceptors. This discovery led scientists to rethink how lighting needs for human health are evaluated. Existing literature provides useful information about how to evaluate and report non-visual spectral sensitivities to light but lacks a unified description. In this paper, key concepts in the existing methods are identified and categorized to formulate a unified framework to assess the non-visual potential of light that is adaptable to a wide range of lighting solutions.