Colin M. Lenton

While light and its photobiological connection is a relatively new discussion in lighting design, it is by no means a new area of study. At the forefront of this research for the past 30 years has been George Brainard, Ph.D., a pioneer in the field based at Thomas Jefferson University in Philadelphia. Years of looking at circadian neuroendocrine and neurobehavioral responses to light in vertebrate species led to a watershed moment in 2001. That was when Brainard and his team published Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor, in which the team of scientists probed deep into the physiology of the human eye, in an attempt to elucidate how it detects light and translates it into a hormonal response. This research led to the game-changing discovery the following year—by the Berson lab at Brown University and the Hattar lab at John Hopkins University—of intrinsically photosensitive ganglion cells in the eye, a development that moved a niche area into mainstream science, and altered the way designers think about light, people, and space.

What fascinates you about light?
As powerful and as useful as light is, it’s shocking how little is known.

What text has impacted your work?
Kendric Smith’s The Science of Photobiology (Springer, 1989). It laid out the techniques, the technologies, [and] the thinking that you need to do for careful, controlled work like this. It [also] explains the numerous mistakes made by some investigators; there have been some pretty dramatic failures.

When did the lighting community realize that light and its photobiological effects had an impact on their design work?
It’s a progression of key discoveries. One was the 1980 demonstration at the National Institutes of Health that showed light could suppress melatonin in healthy humans. In 2001, we published our paper Action Spectrum, which was quickly followed by the discovery of the photosensitive ganglion cells the next year.

What is the most misunderstood aspect of the lighting research you are doing?
We need evidence-based lighting in the design community, along with research validating architectural and lighting design applications as it relates to the basic health effects of light.

What is the future of lighting research?
There is much to be done, first in the area of fundamentals—what is the underlying biology? The second arena is applications. Evidence-based information must be developed.

“I’ve watched how lighting designers have gone from understanding that light might have clinical applications, like in winter depression or sleep disorders, to being something that’s realistic for all architectural spaces. It’s really these two different communities [design and medicine] that are at different stages of thinking about and grappling with the emergent evidence that light affects human health.”George Brainard, Director, Light Research Program, Professor of Neurology, Jefferson Medical College, Thomas Jefferson University