The Light and Health Program at the LRC
The Light and Health program at the LRC bridges the gap between science and applications by striving to better understand how the visual and circadian systems work and what lighting characteristics affect them. The Light and Health program aims to develop the means of applying and measuring light that is effective to both visual and circadian systems.
Learn more about the Light and Health program
Featured Projects

The Dimesimeter
LRC scientists developed the Dimesimeter, a small, unobtrusive research tool for collecting measurements of personal circadian light exposure and activity levels.
Read more.
Watch a short video about the Dimesimeter

Scientists measure and predict the spectral transmittance of the human eyelid
LRC scientists developed a technique to practically and accurately measure eyelid transmittance across the visible portion of the electromagnetic spectrum.
Read more.
Watch an interactive video about lighting principles for older adults:
(Note: You must have Flash v. 10 or later installed to view the presentation. Click here to download Flash player.)
Developing a 24-Hour Lighting Scheme for the Elderly
Lighting designers work with the American Institute of Architects to create a 24-hour lighting plan that promotes positive health, visibility, and stability for older adults.
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Improving Sleep Quality in the Elderly
LRC researchers have demonstrated that blue light therapy is the most effective at stimulating the circadian system when prescribed appropriately. This treatment can help alleviate sleep disorders in elderly adults.
Read more.
Patterns to Daylight Schools for People and Sustainability
The latest pattern book by LRC authors, sponsored by the US Green Building Council, presents model designs for implementing daylighting into school classrooms, corridors, and gymnasiums. With emphasis on human health impact and other daylight metrics, this book compares cost, comfort, visual environment, and energy use among well-known daylighting techniques.
Download the book.![]()
Exposure to Early Evening Sunlight in Spring Delays Sleep Times
In the spring, later sunset and extended daylight exposure delay bedtimes in teenagers, according to researchers at the LRC. Biologically, this increased exposure to early evening light in the spring delays the onset of nocturnal melatonin, a hormone that indicates to the body when it’s nighttime. This extended exposure adds to the difficulties teens have falling asleep at a reasonable hour.
Read more.
Quantifying the Impact of Light on K-12 Students' Performance and Well-being
The LRC received a grant from the U.S. Green Building Council to quantify the impact of daylight and electric lighting on student alertness, performance, and well-being in K-12 schools. The final outcome will be a set of guidelines to enable the development of school building designs to maximize health and performance.
Read more. (View a video clip about this story by clicking here)
First Device to Measure Light as it Impacts the Circadian System
Evidence indicates that exposure to irregular patterns of light and dark can cause circadian disruption, negatively affecting human health. LRC researchers have developed a first-of-its-kind framework for studying the effects of circadian disruption on breast cancer, obesity, sleep disorders, and other health problems.
Read more.
A New Pathway to Alertness
It is well-accepted that the circadian system is maximally sensitive to short-wavelength (blue) light. However, working with the Office of Naval Research, LRC scientists found that red light also increased alertness at night although it did not suppress the hormone melatonin, a marker of the circadian clock..
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To read more, search for related articles, or view a bibliography of published articles, click here.
