2010 article

Harvard Medical School division of Sleep Medicine

Researchers show that green light is effective in eliciting non-visual responses to light such as resetting circadian rhythms, affecting melatonin production and alerting the brain.

Boston, MA – It has been previously shown that blue light plays an important role in impacting the body’s natural internal body clock and the release of hormones such as melatonin, which is connected to sleepiness, by affecting photoreceptors in specialized cells in the eye.  In new research from Brigham and Women’s Hospital (BWH), researchers have found that green light also plays a role in influencing these non-visual responses. This research is published in the May 12 issue of Science Translational Medicine.

“Over the past decade there have been many non-FDA approved devices and technologies marketed for using blue light therapeutically such as blue light boxes for treatment of Seasonal Affective Disorder and circadian rhythm sleep disorders, and glasses that block blue light from reaching the eye,” said Steven Lockley, PhD, a researcher in the Division of Sleep Medicine at BWH and senior author of the paper. “Our results suggest that we have to consider not only blue light when predicting the effects of light on our circadian rhythms, hormones and alertness, but also other visible wavelengths such as green light.”

The entire article can be read at this link.