Tag Archives: non-visual light-sensing system

The Eye’s Nonvisual System

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Photo courtesy of NASA Identifier: 420686main_4 Researchers around the world are following the rocket science of lighting technology: the astronaut-friendly LED lighting being developed and tested for the International Space Station. “If it’s good enough for the space station,” says circadian neuroscientist Steven W. Lockley, “it’s good enough for your house.”

NASA Identifier: 420686main_4
In the accelerating world of electric and natural light research, most fascinating of all is the rocket science of lighting technology: the astronaut-friendly LED lighting system being developed and tested for astronauts aboard the International Space Station. “If it’s good enough for the space station,” says circadian neuroscientist Steven W. Lockley, “it’s good enough for your house.”

Scientists’ journeys are a never-ending process of discovery. And the findings don’t get any bigger than that of a new photoreceptor system in not just the human eye, but in the eyes of all mammals.

As I have learned from my interviews with numerous scientists over the past three years, the most exciting new frontier in light research has to do with this photoreceptor system: the eye’s nonvisual system, which performs the critical job of detecting the wavelengths of light that drive our biology and behavior through the resetting of the master 24-hour — the circadian — clock in the brain.

Circadian neuroscientist Steven W. Lockley explains: Unlike the visual system, this non-image-forming system provides a measurement of environmental light-dark cycles. It tells the brain whether it’s night or day, or winter or summer, which the brain uses to control our daily and seasonal biology.

The workings of this nonvisual system are shaping health and light research around the globe, from medical technology in hospital and healthcare settings, to lighting for professional athletes and sports team facilities, to comfort in our homes.

And then, most fascinating of all, there’s the rocket science of lighting technology: the astronaut-friendly LED lighting being developed and tested for the International Space Station. This highly sophisticated LED wavelength technology is designed to improve astronauts’ sleep, alertness, safety, and work performances in conjunction with the nonvisual light-sensing system of the eye.

A talk I gave in August 2014 at the Better Lights for Better Nights Conference in Dripping Springs, Texas, focused on this groundbreaking research that holds huge implications for lighting applications on Earth.

The bulk of the materials for my presentation were provided by Lockley, an Associate Professor of Medicine at Harvard Medical School and a neuroscientist in the Division of Sleep Medicine and Departments of Medicine and Neurology at Brigham and Women’s Hospital; and Dr. Smith Johnston, then-director of the Aerospace and Occupational Medicine Clinics at NASA’s Johnson Space Center in Houston.

Lockley, a circadian rhythms and light researcher, is a lead adviser of LED lighting for the space station. Everywhere electric light is used, Lockley says, we can do a better job of it. “We’re at the start of a revolution for the application of light,” Lockley told me in a phone interview. “If it’s good enough for the space station, it’s good enough for your house.”

Brand-New Look at an Ancient System

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NASA Identifier: sts092-367-035 In the 21st century, for the first time, scientists are studying the workings of the eye’s ancient photoreceptor system, which evolved before vision. The origins of the nonvisual system possibly date back at least 500 million years. New research about the eye’s light-sensing system is driving high-precision light technology being designed for the International Space Station.

NASA Identifier: sts092-367-035
In the 21st century, for the first time, scientists are studying the workings of the eye’s ancient photoreceptor system, which evolved before vision. The origins of the nonvisual system possibly date back at least 500 million years. New research about the eye’s light-sensing system is driving high-precision LED light technology being designed to improve the health and safety of astronauts aboard the International Space Station.

Unlike the eye’s visual rods-and-cones system, which produces images, the nonvisual system provides a measure of environmental presence and intensity of light. It is composed of photosensitive retinal ganglion cells, which get their light-measurement abilities from a light-sensitive photopigment called melanopsin.

Melanopsin, not to be confused with melatonin or melanin (a pigment that gives color to skin and eyes), shows a peak sensitivity to short-wavelength blue light: the light that most readily activates the brain, suppressing melatonin — the chemical expression of darkness, as termed by pioneer melatonin researcher Russel J. Reiter — and preparing the body’s physiological and psychological systems for daytime activities.

In the 21st century, for the first time, scientists are studying the workings of this ancient photoreceptor system, which evolved before vision. Researchers believe the origins of the nonvisual system possibly date back at least 500 million years, to the branch of animal evolution featuring sea stars and sea urchins. But this photoreceptor system — discovered just over a decade ago, in 2002 — is so small that generations of scientists overlooked it during centuries of research on the eye’s visual processes.

“The discovery of a new sensory apparatus in the human eye after hundreds of years of careful research on the visual system serves as a reminder of how easy it is to miss critically important physiology,” neuroscientist George C. Brainard wrote in the 2005 research article “Photons, Clocks, and Consciousness” (Brainard, John P. Hanifin, Journal of Biological Rhythms).

Brainard, director of the Light Research Program at Thomas Jefferson University whose decades of research helped lead to the discovery of the eye’s nonvisual system, explained in the article that the science of human circadian phototransduction — the process in which light, via detection by the eye’s light-sensing system, is transformed into electrical signals for the brain — was still in its infancy. “Expanding the frontiers of this field will teach us how to better use light for the benefit of humanity,” Brainard wrote.

Brainard is playing a huge role in expanding those frontiers: The neuroscientist continues to work with NASA in developing light for long-duration space travel, including the International Space Station.