A Procedure for Determining Target Illuminances

DiLaura, David L.; Harrold, Rita M.; Houser, Kevin W.; Mistrick, Richard G.; Steffy, Gary R.

doi:10.1582/leukos.2011.07.03001

Cited by 57 publications

(89 citation statements)

References 17 publications

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“…Caregivers were instructed to ensure that participants did not cover the device with blankets or garments. Upon downloading, the RGB values were converted into values of CS [41][42][43] and into values photopic illuminance, the common measure of light in architectural spaces [45]. In order to minimize the impact of skewed data (e.g., a brief increase in CL A due to sunlight hitting the Daysimeter's sensor), geometric mean values for CL A were calculated for transformation into the CS values used in the analysis.…”

Section: Circadian Stimulus (Cs)mentioning

confidence: 99%

Long-Term, All-Day Exposure to Circadian-Effective Light Improves Sleep, Mood, and Behavior in Persons with Dementia

Figueiro

Şahin

Kalsher

et al. 2020

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Background: Persons with Alzheimer's disease and related dementias (ADRD) frequently experience sleep-wake (circadian) cycle disturbances that lead them to remain awake at night, causing stress and fatigue for families and caregivers. Light therapy shows promise as a nonpharmacological treatment for regulating sleep in this population. Objective: We investigated the long-term impact of a circadian-effective lighting intervention on sleep, mood, and behavior problems in persons with ADRD. Methods: This 25-week clinical trial administered an all-day lighting intervention to 47 patients with ADRD in 9 senior-care facilities, employing wrist-worn actigraphy measures and standardized measures of sleep quality, mood, and behavior. Results: The intervention significantly improved Pittsburgh Sleep Quality Index scores, from an estimated mean ± SEM of 11.89 ± 0.53 at baseline to 5.36 ± 0.63 at the end of the intervention. Additional improvements were noted for sleep efficiency data from actigraph measurements. The intervention significantly reduced Cornell Scale for Depression in Dementia scores (mean ± SEM of 11.36 ± 0.74 at baseline and 4.18 ± 0.88 at the end of the intervention) and Cohen-Mansfield Agitation Inventory scores (mean ± SEM of 47.10 ± 1.98 at baseline and 35.33 ± 2.23 at the end of the intervention). Conclusion: A regular circadian-effective daytime lighting intervention can improve sleep at night and reduce depression and agitation in patients with dementia living in controlled environments. More importantly, the positive effects of the tailored lighting intervention on these outcomes appear to be cumulative over time.

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Section: Circadian Stimulus (Cs)mentioning

confidence: 99%

Long-Term, All-Day Exposure to Circadian-Effective Light Improves Sleep, Mood, and Behavior in Persons with Dementia

Figueiro

Şahin

Kalsher

et al. 2020

ADR

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“…To test this hypothesis, we measured the circadian spectral sensitivity using (1) a light exposure time of 12 h instead of brief ≤90-min light exposures; (2) a comparison of 6 different polychromatic overhead ceiling white light-emitting diode (LED) light sources with diverse spectral power distributions to probe circadian spectral sensitivity, instead of the monochromatic light stimuli previously used; (3) exposures to illumination levels recommended by the IES Lighting Handbook for health care and manufacturing work surfaces (540 lux = 50 foot candles, horizontally at table top; DiLaura et al, 2011 ), providing 254 to 323 lux vertical illuminance at the cornea of the eye; and (4) measurements of the total 12-h nocturnal (2000-0800 h) suppression of melatonin (area under the curve) as a circadian disruption biomarker ( Mirick and Davis, 2008 ) that has direct relevance to health outcomes ( Hill et al, 2015 ).…”

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confidence: 99%

Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

2020

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Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.

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“…As part of this undertaking, the units employed for illuminance recommendations are being reconsidered. In the 10th Edition Handbook, recommended illuminance targets are in units of lux and determination of illuminance targets in footcandles is based on a soft conversion of 10 footcandles to 100 lux (DiLaura et al 2011a(DiLaura et al , 2011b.…”

Section: Footcandles or Lux In Ies Publications?mentioning

confidence: 99%