Better Than Blue Light

Research carried out at the University of Washington has demonstrated that the intrinsically photosensitive retinal ganglion cells get significant input from the red, green and blue cones involved in color vision. Research shows that under the right circumstances, signals from the cones can be much stronger than those generated by Melanopsin. The body clocks of our Paleolithic human ancestors were synchronized by light from colorful sunsets and research shows that patterns of color and intensity similar to dawn and dusk have more powerful effects on ipRGCs than simple blue lights. Understanding the role of patterns of light on cones in driving ipRGCs will lead to much better ways of controlling circadian rhythms than is possible with current technologies.

LEARNING OBJECTIVES

• Understand how light therapy can boost attention, reaction times, and mood be used as an efficient way to help people “reset” circadian rhythms and ameliorate jet lag, shift work disorder, and SAD.
• The reason blue lights are more effective than other colors is only partly because the photopigment, Melanopsin, in retinal ganglion cells that project to the SCN is most sensitive to blue light.
• In addition to Melanopsin, intrinsically photosensitive retinal ganglion cells are highly sensitive to the patterns of input from the red, green and blue cone photoreceptors involved in color vision.
• Colored patterns of light on the cones can be used more efficiently than blue light to synchronize our body clock and can be used to avoid and counteract light stimulation that disrupts our rhythms.