This Recommended Practice (RP) is the implementation companion to IES TM-18-18, Light and Human Health: An Overview of the Impact of Optical Radiation on Visual, Circadian, Neuroendocrine, and Neurobehavioral Responses1 in that it provides recommendations for
translation of the basic science of how light affects visual, circadian, neuroendocrine, and neurobehavioral responses in daytime interior environments, such as those found in schools and offices. IES TM-18-18 reviewed the discovery of melanopsin and the evidence demonstrating that these visual, circadian, neuroendocrine, and neurobehavioral responses can be anatomically—and functionally—distinct from visual responses.

This document includes the major advances achieved since the publication of IES TM-18-18 in understanding the physiology by which light mediates circadian, neuroendocrine, and neurobehavioral responses; however, this document does not supplant IES TM-18-18. For a more complete understanding of the topic, this RP should be read as a companion to IES TM-18-18.