Studies have shown that long periods of staring at TVs and computer screens damages your eyesight. You have to be mindful of your working conditions and take an appropriate number of breaks to give your eyes – and your body – a break. One of the easiest exercises I use is to alternate focus between near objects (a foot or two away) and far objects (the next room over or outdoors, if possible).
I’ve recently learned that there’s more at stake – your sleep. Your body’s internal clock (circadian rhythm) is primarily regulated by your environment. Stand outside in the sun and your body knows it’s day. Sit inside a dark room and your body believes it’s night. The quantity and type of light entering your eyes determines your body’s response.
Unfortunately, the light emitted by all your electronic devices (TV, computer, cell phone, laptop) is the wrong “temperature”. They tell your body that it is still day, even if it’s long past your bed time.
Technically, color temperature is defined as the spectrum of light emitted by a celestial black body (a star) at a given temperature (3000 kelvin, 5000 kelvin, etc). Practically, it just represents the color of light (a blue star, a red star, or our yellow/orange sun). Hotter/brighter stars tend towards blue and cooler/dimmer stars tend towards red.
For creatures on Earth, blue light has always signaled daytime and reddish/orange light has signaled sunset. Our rhythms are set to respond to these signals and keep us awake when the light is blue. Staring at a computer screen with a “bluer” color temperature will keep you awake even when you should feel tired. Note that even if your screen doesn’t look blue to you, blue is a significant component of the light being emitted (white light contains all colors in the spectrum).
Many computer monitors and television screens have settings for color temperature. Particularly for high-end computer monitors used in printing and graphics, the color temperature can be quite important. If you’ve ever played with the settings, you’ll have seen that the different settings make the screen “redder” or “bluer”. You’ll probably also get the feeling that the colors don’t look right.
Thankfully, several people have already figured this out and saved us a lot of trouble. Applications are available which will set the appropriate color temperature based on your location and the time of day. Morning and afternoon will have the correct hotter color temperatures. As the day wanes, the temperatures will fade to the cooler colors which don’t keep you awake. You can continue working into the night if you wish, but your body won’t be receiving false signals.
PC (Windows), Mac and Linux
Linux/Unix (my preferred option)
Now, you might think this is all hocus-pocus. Below, I’ll suggest a very convincing, painful way to prove the point. The reason it works is that once your body has adjusted to the soft light of the evening, bright daylight borders on painful (something you’ve probably experienced after walking from a dark room out into sunlight). Your eyes will hurt.
- Install one of the two applications above and set your location.
- Wait until evening, when you’ll see that the colors have shifted. If your home lighting is bluish-white, you’ll need to think about changing that, too.
- While staring at the screen, turn off f.lux or redshift (whichever you’ve chosen).
- Grimace as your eyes re-adjust to the glaring light.