The type lighting that we use can have a profound impact on our sleep habits and health. Seasonal affective disorder.
http://en.wikipedia.org/wiki/Seasonal_affective_disorder
“Light therapy uses a lightbox which emits far more lumens than a customary incandescent lamp. Bright white “full spectrum” light at 10,000 lux, blue light at a wavelength of 480 nm at 2,500 lux or green (actually cyan or blue-green) light at a wavelength of 500 nm at 350 lux are used, with the first-mentioned historically preferred.
“Bright light therapy is effective with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source for 30–60 minutes.”
Oddly enough, experiments have shown that the light does not necessarily need to enter through the eyes, but can also be used on the skin where there are numerous capillaries neat the surface, such and in the fold of the elbows and the backs of the knees. “Cool” lights attached to those places can provide good effects because of much longer periods of exposure, during sleep.
I have SAD (Seasonal Affect Disorder), as did my mother, so the condition may be congenital .
The fact that I am located downwind from the Great Lakes clouds and storms affects the amount of sunlight to which I am exposed and aggrivates the condition.
I participated in a 6 week long Medical University test and found out that I benefitted from 'light therapy' by one hour exposures,5 times per week, to "full spectrum lights".
Commercially made lights are too expensive; I improvised, and made my own light box system for under $20.oo rather than pay $250 - $750 + for commercial lights.
I went to a farm/tractor supply store and got a 'chicken brooder light' and aluminum reflector for under $10.oo, which comes with a clamp (allows position anywhere) .
For a light source ,I used a "full spectrum", or a "Grow Light"(used in horiculture) of 150 Watts which contains the blue/green light full spectrum.
With the clamp, I was able to mount the light alongside the TV while watching,or attach to the side of the bookcase if I was reading a book, or listening to the radio.
Distance from the light source varies from 6-8 feet as even peripheral vision of "full spectrum" light is a benefit.
the further the distance, the longer the exposure , either direct, or peripheral.
The clamp makes it versatile and convienient.