If you have trouble falling asleep at night and find yourself dragging in the mornings, blue-light-blocking glasses could get your body clock back on track.
The amber color of the lenses has been found to shield the eyes from a major culprit in the sleep wars: short-wavelength light, otherwise known as blue light.
The glasses were developed by scientists at LowBlueLights.com, a spinoff of Photonic Developments LLC and its parent, the Lighting Innovations Institute at John Carroll University in Cleveland. They sell for $80 at www.lowbluelights.com.
Physicist Richard Hansler, director of the institute and a founding partner of Photonic Developments, said research has confirmed that eye exposure to blue light suppresses the body's production of melatonin -- that's a sleep hormone produced by the pineal gland when the eyes are in darkness.
Blue light is a major emanation from television and computer screens, fluorescent light bulbs and, to a lesser extent, incandescent light bulbs. That means people who are glued to the tube, surfing the Web or reading by lamp light late into the night are unwittingly pushing back their body's "start time" for melatonin production.
"If the eyes are exposed to light at bed time, it will prevent the pineal gland from producing melatonin until you go into darkness," Dr. Hansler said. "If the light continues for a longer time, it can actually prevent the body from making melatonin that whole night."
Once the body does begin making the hormone, he said, it normally keeps doing so for seven to eight hours. This is why so many people are dragging in the early mornings, until their eyes are exposed to enough blue light to suppress the melatonin.
Sitting in a darkened room for two hours before bed would help reset the melatonin clock, but that's an impractical solution for many people.
However, Dr. Hansler said, wearing blue-light-blocking glasses while going about one's business in the evening would have a similar effect. (The company also sells amber-colored light bulbs and filters that attach to computer and TV screens).
Melatonin production also depends on one other factor, he said -- the setting of one's body clock from the previous night. For that reason, blue-light-blocking measures might take a few days to improve sleep. But once a rhythm is established, he said, most people will sleep better at night.
Sally Kalson can be reached at firstname.lastname@example.org or 412-263-1610.