Useful info found by Parox –
Free app adjusts color on monitors to prevent disruption of sleep cycle
Blue light emitted from computer screens can interrupt the hormone that regulates our sleep cycles, studies have shown.
I stare at screens almost every waking hour.
Computer monitor. Laptop. TV. Tablet. Smartphone.
So I've tested a few ways to ease the strain on my eyes - and, in the process, learned about something that might be helping me in non-waking hours, too.
It's about the light that these screens emit. It typically has a cool blue undertone, whether you notice it or not. (Think of your next-door neighbor's TV seen through a window at night.) That's fine during the day - screen light was designed to mimic the tones of daylight. But my screen time lasts long after dark. And that's the problem.
Humans evolved to respond to darkness by producing melatonin, the hormone that regulates the sleep cycle. But our light-sensitive pineal gland near the center of the brain responds to blue light by suppressing melatonin, causing us to wake up.
When we see too much blue light in the late evening, it delays or disrupts the melatonin rush. In other words, my iPad can keep me up even after I turn it off.
But just as technology can cause this problem, it offers a solution as well. Enter F.lux, a desktop application that adjusts a computer screen's color throughout the day. During daylight hours, the screen's undertone is the familiar blue. As sundown approaches, it begins transitioning to a warm shade of red-orange. In the morning, it's cool blue again.
More
http://articles.chicagotribune.com/2...steven-lockley
http://www.washingtonpost.com/wp-dyn...021404136.html