The lighting environment, its metrology and non-visual responses
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In 2018, the International Council on Circadian and Neurophysiological Photometry (CIE S 026:2018) provided lighting professionals and field researchers in chronobiology with a method to characterize light exposures with respect to non-visual photoreception and responses as discussed by the authors.Abstract:
International standard CIE S 026:2018 provides lighting professionals and field researchers in chronobiology with a method to characterize light exposures with respect to non-visual photoreception and responses. This standard defines five spectral sensitivity functions that describe optical radiation for its ability to stimulate each of the five α-opic retinal photoreceptor classes that contribute to the non-visual effects of light in humans via intrinsically-photosensitive retinal ganglion cells (ipRGCs). The CIE also recently published an open-access α-opic toolbox that calculates all the quantities and ratios of the α-opic metrology in the photometric, radiometric and photon systems, based on either a measured (user-defined) spectrum or selected illuminants (A, D65, E, FL11, LED-B3) built into the toolbox. For a wide variety of ecologically-valid conditions, the melanopsin-based photoreception of ipRGCs has been shown to account for the spectral sensitivity of non-visual responses, from shifting the timing of nocturnal sleep and melatonin secretion to regulating steady-state pupil diameter. Recent findings continue to confirm that the photopigment melanopsin also plays a role in visual responses, and that melanopsin-based photoreception may have a significant influence on brightness perception and aspects of spatial vision. Although knowledge concerning the extent to which rods and cones interact with ipRGCs in driving non-visual effects is still growing, a CIE position statement recently used melanopic equivalent daylight (D65) illuminance in preliminary guidance on applying "proper light at the proper time" to manipulate non-visual responses. Further guidance on this approach is awaited from the participants of the 2nd International Workshop on Circadian and Neurophysiological Photometry (in Manchester, August 2019). The new α-opic metrology of CIE S 026 enables traceable measurements and a formal, quantitative specification of personal light exposures, photic interventions and lighting designs. Here, we apply this metrology to everyday light sources including a natural daylight time series, a range of LED lighting products and, using the toobox, to a smartphone display screen. This collection of examples suggests ways in which variations in the melanopic content of light over the day can be adopted in strategies that use light to support human health and well-being.read more
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Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults
Timothy M. Brown,George C. Brainard,Christian Cajochen,Charles A. Czeisler,John P. Hanifin,Steven W. Lockley,Robert J. Lucas,Mirjam Münch,John O’Hagan,Stuart N. Peirson,Luke L. A. Price,Till Roenneberg,Luc J. M. Schlangen,Debra J. Skene,Manuel Spitschan,Céline Vetter,Phyllis C. Zee,Kenneth P. Wright +17 more
TL;DR: Recommendations for lighting are provided, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard.
Journal ArticleDOI
Predicting melatonin suppression by light in humans: Unifying photoreceptor‐based equivalent daylight illuminances, spectral composition, timing and duration of light exposure
TL;DR: The model provides initial and general guidance to lighting practitioners on how to combine spectrum, duration and amount of light exposure when controlling non‐visual responses to light, especially melatonin suppression.
Journal ArticleDOI
The interindividual variability of sleep timing and circadian phase in humans is influenced by daytime and evening light conditions
Charikleia Papatsimpa,Luc J. M. Schlangen,K.C.H.J. Smolders,Jean-Paul M. G. Linnartz,Y.A.W. de Kort +4 more
TL;DR: In this article, the authors used a mathematical model of the human circadian pacemaker to understand how light in the built environment changes the chronotype distribution in the population, and they showed that when individuals spend their days in relatively dim light conditions, this not only results in a later phase of their biological clock but also increases interindividual differences in circadian phase angle of entrainment and preferred sleep timing.
Journal ArticleDOI
Individual differences and diversity in human physiological responses to light
Yeonkwon Jung,Guohua Chen +1 more
TL;DR: In this paper , the authors discuss the fundamentals and individual differences in the non-visual effects of light and propose a set of actions to improve their evidence database to be more diverse: understanding systematic bias in the evidence base, dedicated efforts to recruit more diverse participants, routine deposition and sharing of data, and development of data standards and reporting guidelines.
Journal ArticleDOI
Effects of Daytime Electric Light Exposure on Human Alertness and Higher Cognitive Functions: A Systematic Review
TL;DR: In this paper , a systematic review conducted on articles examining the effects of daytime electric light exposure on alertness and higher cognitive functions was conducted. But the relationship between light exposure and higher cognition was not as straightforward as the alerting effect.
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