Lighting Research Center

Advancing the effective use of light for society and the environment

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Light & Health

Additional Light and Health Research ProjectsLight and Health applications

What has been learned about light's role in human health so far, from raising alertness in night shift workers to entraining the circadian system of sleep-deprived adolescents to reducing the risk of falls in older adults, can have broader applications. LRC researchers are continuing to investigate new fields of research and conduct ongoing, smaller-scale projects to learn more about light and health. These projects can have widespread applications to other areas of focus in the Light and Health program, or simply be a way to apply what has been learned to find practical solutions to improving overall wellbeing.

Modeling Circadian Phototransduction

Value Metrics for Better Lighting

"Light" is commonly used to refer to the visual stimulus, rather than a response from a biological system. However, the circadian system's reaction to light is not the same as the visual system. The LRC is continuing to create new lighting metrics, redefining units and tools used to measure lighting quantity and quality. The LRC has proposed a new model of human circadian phototransduction, as well as definitions of the terms circadian light and circadian stimulus.

Summaries of select research projects are linked below in PDF format. More information about these proposed metrics and ways to increase the benefits of lighting can be found in the recent publication, Value Metrics for Better Lighting.

Modeling the spectral sensitivity of the human circadian system

Circadian Light Defined pdf logo

    Related Publication:
  • Rea MS, Figueiro MG, Bierman A, Bullough JD. 2010. Circadian light. Journal of Circadian Rhythms, 8(1):2.

Circadian Effectiveness of Polychromatic Lights: Suppressing Human Nocturnal Melatonin pdf logo

A second kind of light: A model of phototransduction by the human circadian system pdf logo

Animal Research

LRC researchers are investigating the ways that light can impact animal (as well as human) health. Recently, LRC researchers have used the Daysimeter in their work with lemurs and cows to measure light/dark and activity/rest patterns of these animals. LRC also conducted studies on rats and mice to better understand their phototransduction mechanisms. The LRC has worked in partnership with Duke University's Lemur Center and the Cornell University Cooperative Extension.

Summaries of select research projects are linked below in PDF format.

Bridging Animal Models to Human Health Outcomes pdf logo

Circadian Rhythms in Lemurs pdf logo

Exploring Bovine Benefits of Increased Light Exposure pdf logo


Light as a Controlling Stimulus for Behavior Cancer Research: Bridging Human Exposures to Animal Models for Parametric Investigations 

NICU Standards

LRC researchers have contributed to the evaluation and creation of design standards for newborn intensive care units, or NICUs. 

Recommended Standards for Newborn ICU Design
Report of the Eighth Census Conference on Newborn ICU Design - January 2012
Committee to Establish Recommended Standards for Newborn ICU Design

    Related Publications:
  • Rizzo P, Rea, MS, White R. 2010. Lighting for Today's Neonatal Intensive Care Unit. Newborn and Infant Nursing Reviews, 10(2):107-113.
  • Figueiro MG, Rea MS, Boyce P, White R, Kolberg K. 2001. The effects of bright light on day and night shift nurses' performance and well being in the NICU. Neonatal Intensive Care. The Journal of Perinatology-Neonatology, 14(1):29-32.
Light through Closed Eyelids

The LRC developed a mathematical model of human eyelid transmittance. This information allowed LRC researchers to develop a light mask that can be used phase shift the timing of the circadian clock while patients are asleep. Light applied during sleep is more effective at shifting the biological clock than light applied at other circadian times.

Feasibility Demonstration of Light through Closed Eyelids to Promote Sleep Health pdf logo

  • National Institute on Aging (R01AG042602)

Pulsing Blue Light During Sleep Phase Shifts DLMO pdf logo

  • National Institute on Aging (R01AG042602)

Blue Light Pulses Through Closed Eyelids Suppress Melatonin

Light through the Eyelids and Its Effect on Melatonin pdf logo

Measuring the Spectral Transmittance of the Human Eyelid pdf logo

Media Coverage

LRC research on light and health applications has been featured in various media reports. A select sampling is below. For more featured media, visit our Newsroom Media Page.

Quantifying Circadian Light and Its Impact
Architectural Lighting - February 2017
Melanopic lux is the wrong metric for describing circadian-effective light. Here is a better alternative.

How to design circadian lighting - by top scientists
LUX Magazine - December 2016
US scientists have developed a special tool to help designers create lighting installations which affect the sleep-wake cycle.

TEDMED: Mariana Figueiro - May 5, 2015
How can we harness the power of light to improve health? Mariana Figueiro, Light & Health Program Director at the Lighting Research Center, explains in her TEDMED talk. Watch the video. For more information, also see Dr. Figueiro's TEDMED guest blog post.

Lemurs' neck bling tracks siestas, insomnia
Duke Research Blog - November 2013
In a study to appear in the American Journal of Physical Anthropology, Duke researcher Ken Glander and colleagues at Rensselaer Polytechnic Institute's Lighting Research Center outfitted twenty lemurs at the Duke Lemur Center with Daysimeters to study the animals' daily ups and downs. The results could help researchers understand the sleep disturbances common among people with Alzheimer's or other forms of dementia, and whether light therapy could help reset their internal clock for a more solid night's sleep.

View a list of publications, journal articles, and conference papers on light and health issues by Lighting Research Center scientists.








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