Research Roadmap for Healthful Interior Lighting Applications
|Publication Date:||1 January 2016|
Evidence that a separate photoreceptor detects irradiance and provides the entrainment signal for circadian regulation (Berson et al. 2002; Hattar et al. 2002) has galvanized lighting researchers, manufacturers, and designers (Bommel and Beld 2004; DiLaura 2005). Some have argued that lighting applications should rapidly change to adopt this new information (Bommel 2005; Bommel and Beld 2004; German Institute for Standardization (DIN) 2013), whereas others have called for a more cautious approach (Boyce 2006).
CIE published the first consensus report concerning the ocular effects of light on physiology and behaviour in 2004 (CIE 158:2004/2009), and convened expert symposia on the subject in 2004 (CIE 2004) and 2006 (CIE 2006). The first symposium emphasized the evidence that light has effects on people beyond vision ("light and health"), whereas the second event focused more on the potential applications of this knowledge ("lighting and health"). The emphasis on application continued in 2007 with a workshop at the 26th Session of the CIE in Beijing (Brainard and Veitch 2007). Workshop participants expressed two diverging opinions: "Time to forge ahead" and "Take care to avoid unintended consequences". CIE Technical Committee 3-46 was formed in response to these competing influences.
The Terms of Reference for TC 3-46 are:
"This TC will review relevant CIE publications (CIE 158:2004 and the two CIE expert symposia on light and lighting and health in 2004 and 2006) and the more recent scientific literature to identify the information that is needed before such lighting application may take place. The output will be a technical report which will describe a research roadmap intended to stimulate fundamental research into questions relevant to lighting applications."
The World Health Organization definition of health underlies this report: "Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (World Health Organization (WHO) 1948). We seek knowledge of the effects of light that will result in positive psychological and physiological states and rhythms in order to support evidence-based lighting recommendations. That said, the committee has focused primarily on the research directions related to the CIE publications referenced in its Terms of Reference. This means, for example, that research related to spatial appearance judgements is not included (but see Veitch and Galasiu (2012) for a consideration of this topic).
Research productivity in all aspects of light, lighting, and health has been prodigious in the years over which this TC has worked; but it remains the considered opinion of the committee members that in many areas we remain in the early days of understanding what will constitute a healthful lighting application in any specific installation. Even in domains where there has been the greatest activity, it can be difficult to derive applications guidance because of limitations of research design or reporting.
This document is not a comprehensive research review; it is not a sequel to publication CIE 158 (CIE 2004/2009). Rather, it sets out the questions for which those who write standards, recommendations, and codes will need answers if these documents are to provide integrated guidance incorporating goals for health and well-being along with visual requirements. The purpose of this document is to clarify the research questions (Clause 2) and to set out some simple guidance for research methods (Clause 3) to speed the work of developing knowledge that can be put into practice. Clause 4 provides insight into the gap between fundamental research and application.