**5. Existing and Developing Regulations Related to the Non-visual E**ff**ects of Light Absorbed through Our Eyes**

In 2011, the European Commission published the Green Paper "Let's light up the future: Accelerating the deployment of innovative lighting technologies". This document raises concerns about blue light's potential risks to vision. The Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) released a document in 2012 entitled "Health effects of artificial lights", which explored the scientific evidence on the potential impacts of artificial light radiating into the visible spectrum on human health [107].

In 2013, the International Commission on Illumination (CIE) published the "Report on the first international workshop on circadian and neurophysiological photometry". This document features multiple references to the article mentioned in this paper by Lucas et al. [108]. This CIE paper describes the five photoreceptors located in the human eye (the three types of cones, the rods, and the ipRGCs) and notes that they all influence the stimulation of melatonin synthesis, although the paper concludes that much remains to be determined about their mechanisms of action. The importance of pupil contraction in the non-visual effects of light absorption is also mentioned [109].

In 2016, the CIE [110] published the "Research Roadmap for healthful interior lighting applications", which refers to multiple studies with statements such as the following.


In 2017, the CIE [111] held a working meeting: the CIE stakeholder workshop for temporary light modulation standards for lighting systems. Current lighting systems vary widely in that their light output shows temporary variations or flickering (temporal light modulation, TLM). Temporal light modulation (TLM) is known to affect human visual perception, neurobiology, and behavior, sometimes adversely. Many organizations have developed standards and regulations, and certifying organizations have been active in research focused on these issues. Some researchers are studying these effects, but such activities are currently uncoordinated and at risk of being inefficient. The CIE, with support from Energy Efficiency Canada, the national association of electricity manufacturers, Philips Lighting, BC Hydro, and Research Canada, agreed to hold a stakeholder workshop in Ottawa, Canada on 8–9 February 2017. The objective of this meeting was to create a roadmap for research, offer recommendations, and develop regulatory activities related to the temporary variations of light from

lighting systems to accelerate the international regulatory development process in an efficient manner and avoid the overlap and duplication of such efforts.

In 2018, the CIE [112] published a document titled "ED/IS 026/E:2018 CIE System for metrology of optical radiation for light responses influenced by intrinsically-photosensitive retinal ganglional cells". The introduction of this paper states that light is the main synchronizer of human biological clocks and may result in the acute suppression of nocturnal melatonin release. While the functioning of cones and rods in the vision process are well known, the function of spectral sensitivity and a quantitative and qualitative analysis of melatonin-based photoreception remain unexplored.

The aim of this international standard is to define the role of spectral sensitivity, quantify it, and measure it to describe visible radiation and UVA according to its ability to stimulate each of the five types of photoreceptors, i.e., how much each contributes to the melatonin content of intrinsically photosensitive retinal ganglion cells (ipRGCs), and thus their mediation on the non-visual effects of light on humans. This international standard is applicable to visible optical radiation of 380–780 nm.

This international standard does not give information on particular lighting applications or a quantitative prediction of the response of ipRGCs; it also, does not mention health or safety issues, such as the results of light treatments, flickers, or photobiological health.

Experts around the world are collaborating on the development of this standard which states that light is the main synchronizer of human biological clocks and can lead to an acute suppression of melatonin release at night.
