Light & Engineering Vol. 23, No. 4, pp. 4-5, 2015 Svetotekhnika No. 6, 2015, pp. 39-40 CIE Statement on Non-Visual Effects of Light RECOMMENDING PROPER LIGHT AT THE PROPER TIME BACKGROUND The defi nition of light identifi es it as the electromagnetic radiation that stimulates vision. <...> However, we now know conclusively that photoreception in the eye leads not only to vision but also to effects on human physiology, mood and behavior, often summarized as non-visual effects of light. <...> It was fueled by the revolutionary detection of a new class of photoreceptors in the human eye that detect optical radiation but do not contribute to image formation. <...> We are learning now that these photoreceptors infl uence many other processes as well. <...> In recent years the catchphrase “Human-Centric Lighting” ( HCL) has come to describe lighting that is intended to address all of these effects. <...> The basic evidence for the new photoreceptors, called melanopsin-containing or intrinsic photosensitive retinal ganglion cells (ipRGC), and the fi rst identifi ed implications for lighting have been summarized in CIE158:2004 (which was revised to become 158:2009, including Erratum 1). <...> CIE continued to explore this topic with two expert symposia in 2004 and 2006, with workshops at its Session meetings in 2007 and 2011, and by initiating several technical committees. <...> Other societies also responded with events, debates, and discussion concerning how best to incorporate this knowledge into lighting practice. <...> Scientists, the lighting industry, lighting designers and other stakeholders in the lighting community have continued to identify options and to design products and solutions that make use of non-visual lighting effects in a benefi cial way, despite the fact that the established knowledge in this fi eld is still premature. <...> Among the few points of general agreement is that the non-visual ef4 fects of light exposure depend on the spectrum, intensity, duration, timing and temporal pattern (light history) of the light exposure. <...> In order to give further guidance to all interested parties on the future use of non-visual effects of light for human health and performance, while at the same time avoiding possible risks, CIE will be presenting two new publications on the state of science in this exciting research fi eld: 1 <...>