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Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
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Circadian and visual photometry.

Luke L A Price1, Peter Blattner2

  • 1Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Harwell Campus, Didcot, Oxfordshire, United Kingdom; Secretary of Division 6 for Photobiology and Photochemistry of CIE, Vienna, Austria.

Progress in Brain Research
|August 8, 2022
PubMed
Summary
This summary is machine-generated.

Photometry standards are evolving to include the impact of melanopsin, a newly understood retinal photopigment. This update reflects light

Keywords:
CircadianColorimetryMelanopsinNon-visualPhotobiologyPhotometrySpectroradiometryStandards

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Area of Science:

  • Optometry and Vision Science
  • Photobiology
  • Metrology

Background:

  • Photometry, the measurement of visible light, traditionally relies on models of human eye response established in 1931 by the International Commission on Illumination (CIE).
  • These standards, based on rod and cone photoreceptor input, have governed light measurement for decades.
  • Recent discoveries highlight the role of melanopsin in intrinsically photosensitive retinal ganglion cells (ipRGCs) influencing circadian and neurophysiological responses.

Purpose of the Study:

  • To outline current photometry standards and their definitions.
  • To explain the relationship between classical photoreceptors and newer understanding of melanopsin-driven responses.
  • To discuss the implications of updating photometry standards with modern physiological data.

Main Methods:

  • Review of historical and current International Commission on Illumination (CIE) standards for photometry and colorimetry.
  • Analysis of spectroradiometry data and physiological models of human visual response.
  • Examination of the spectral sensitivity of melanopsin and its role in ipRGCs.

Main Results:

  • CIE S 026:2018 is a significant advancement, incorporating melanopsin's spectral sensitivity for the first time.
  • The standard acknowledges the contribution of ipRGCs, alongside rods and cones, to light-mediated responses.
  • Updating photometry standards with current physiological data is expected to yield consistent changes in measurements related to these accessory visual functions.

Conclusions:

  • The evolution of photometry standards is crucial for accurately measuring light's impact beyond vision.
  • Incorporating melanopsin sensitivity represents a paradigm shift in understanding light's biological effects.
  • Future photometry will better account for the complex interplay of photoreceptors in human physiological responses to light.