Circadian Phase Delay Induced by
Phototherapeutic Devices.
Paul MA, MillerJC,. Gray G, Buick
F, Blazeski S, Arendt J.
Aviation, Space, and Environmental
Medicine. July 2007; 78(7):645-52
"Introduction: The Canadian Forces has initiated a multiple study project to optimize circadian phase changes using appropriately timed phototherapy and/or ingestion of melatonin for those personnel on long-range deployments and shift workers. The work reported here compared four phototherapeutic devices for efficacy in effecting circadian phase delays."
"Conclusions: The [Sunnex Biotechnololgies] light tower was the best device, producing melatonin suppression and circadian phase change while relatively free of side effects.""Light tower (Sunnex Biotechnologies, Winnipeg, Manitoba, Canada; www.sunnexbiotech.com) two towers of two fluorescent light tubes per tower, each tower about 45 cm high with one tower mounted on each end of the base plate. The eye-level light intensity at 60 cm from the eye was about 350 lx. The light tower emits monochromatic light of 500 nm (green light) and is powered by standard electricity (AC)."
See graph below for comparison of melatonin suppression and phase shifts
NOTE:The standard measures for light intensity in physics or photobiology is energy (microwatts per sq cm), or photon count.
This paper confirms that light from a Lo-LIGHT tower is more than 20 times as efficient as blue light emitting devices like the Litebook (465 nm).
One lux of 465 nm blue light has over 4 times the energy (4.37 times) as measured in watts per sq. m than does one lux of 500 nm green light; Therefore 1500 lux from a Litebook provides about 20 times the energy or photon count than 350 lux from a Lo-LIGHT tower.
1500 lux of 465 nm blue light has the same energy as (4.37x1500=) 6,500 lux of green 500 nm light.
The above graph shows that 350 lux GreenLIGHT tower was much more effective in melatonin suppression and induced twice as long of a phase shift as did 1500 lux blue light (465 nm) from the Litebook, even though it provides only about 5% of the light intensity - when measured by energy/photon-count.
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