This paper documents the spectral and spatial performance characteristics of two new versions of the Daysimeter, devices developed and calibrated by the Lighting Research Center to measure and record personal circadian light exposure and activity levels, and compares them to those of the Actiwatch Spectrum. Photometric errors from the Daysimeters and the Actiwatch Spectrum were also determined for various types of light sources. The Daysimeters had better photometric performance than the Actiwatch Spectrum. To assess differences associated with measuring light and activity levels at different locations on the body, older adults wore four Daysimeters and an Actiwatch Spectrum for seven consecutive days. Wearing the Daysimeter or Actiwatch Spectrum on the wrist compromises accurate light measurements relative to locating a calibrated photosensor at the plane of the cornea.
Get full access to this article
View all access options for this article.
References
1.
ReaMSFigueiroMGBiermanABulloughJD. Circadian light. Journal of Circadian Rhythms2010; 8: 2–2.
2.
ZeitzerJMKhalsaSBBoivinDBDuffyJFShanahanTLKronauerRE. Temporal dynamics of late-night photic stimulation of the human circadian timing system. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology2005; 289: R839–R844.
3.
WyszeckiGStilesWS. Color Science: Concepts and Methods, Quantitative Data and Formulae, 2nd. New York, NY: John Wiley and Sons, 1982.
4.
BiermanAKleinTRReaMS. The Daysimeter: a device for measuring optical radiation as a stimulus for the human circadian system. Measurement Science and Technology2005; 16: 2292–2299.
KripkeDFHahnEKGrizasAPWadiakKHLovingRTPocetaJSShadanFFCroninJWKlineLE. Wrist actigraphic scoring for sleep laboratory patients: algorithm development. Journal of Sleep Research2010; 19: 612–619.
7.
ThorneHCJonesKHPetersSPArcherSNDijkDJ. Daily and seasonal variation in the spectral composition of light exposure in humans. Chronobiology International2009; 26: 854–866.
8.
PriceLKhazovaMO’HaganJ. Performance assessment of commercial circadian personal exposure devices. Lighting Research and Technology2012; 44: 17–26.
9.
MillerDFigueiroMGBiermanASchernhammerEReaMS. Ecological measurements of light exposure, activity and circadian disruption. Lighting Research and Technology2010; 42: 271–284.
10.
ReaMSBiermanAFigueiroMGBulloughJD. A new approach to understanding the impact of circadian disruption on human health. Journal of Circadian Rhythms2008; 6: 7–7.
11.
FigueiroMGReaMS. Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students. NeuroEndocrinology Letters2010; 31: 4–4.
12.
ReaMSBronsJAFigueiroMG. Measurements of light at night (LAN) for a sample of female school teachers. Chronobiology International2011; 28: 673–680.
13.
SharkeyKMCarskadonMCFigueiroMGZhuYReaMS. Effects of an advanced sleep schedule and morning short-wavelength light exposure on circadian phase in young adults with late sleep schedules. Sleep Medicine2011; 12: 685–692.
14.
Commission International de l'Éclairage, Methods of Characterizing Illuminance Meters and Luminance Meters: Performance, characteristics and specifications. 1987, Vienna, Austria: Commission International de l'Éclairage.
15.
Van Derlofske J, Bierman A, Rea MS, Ramanath J, Bullough JD. Design and optimization of a retinal flux density meter. Measurement Science and Technology 2002; 13: 821–828.
16.
Deutsches Institut für Normung. Photometry; Classification of Illuminance Meters and Luminance Meters, Germany. Deutsches Institut für Normung NA 058-00-03 AA - Photometrie; DIN 5032-7, 1985.
17.
FolsteinMFFolsteinSEMcHughPR. Mini-mental state: a practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research1975; 12: 189–198.
18.
MorrisJNFriesBEMorrisSA. Scaling ADLs within the MDS. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences1999; 54: M546–M553.
19.
ReaMSFigueiroMGBulloughJDBiermanA. A model of phototransduction by the human circadian system. Brain Research Reviews2005; 50: 213–228.
20.
IESNA. Lighting Handbook: Reference and Application. Rea MS, (ed.), 9th Edition. New York, NY: Illuminating Engineering Society of North America, 2000; 8: 7.
21.
FigueiroMGReaMS. Evening daylight may cause adolescents to sleep less in spring than in winter. Chronobiology International2010; 27: 1242–1258.
22.
KloogIPortnovBARennertHSHaimA. Does the modern urbanized sleeping habitat pose a breast cancer risk?Chronobiology International2011; 28: 76–80.
