Researchers say that a two-hour exposure a self-luminous “backlit” display causes melatonin suppression, which can lead to delayed bedtimes. F.lux, an OS X utility by Stereopsis, aims to solve this problem without any visits to the doctor.Flux is a neat little utility that makes the color of your computer's display adapt to the time of day. Just punch in your zip code or the name of your home town and it will give your Mac’s screen a warm tint at night, an a complementary sunlight tint during the day.
The developers themselves say, “It's even possible that you're staying up too late because of your computer. You could use f.lux because it makes you sleep better, or you could just use it just because it makes your computer look better.”
There are two separate versions to download, one for Leopard users and above, the other for PowerPC users who are running older versions of OS X. Enjoy!
Download F.lux for OS X (Free)