Lately, the blue light from screens, phones and tablets has received much attention. It is found that the blue light from the screens inhibits the production of "fatigue hormon" melatonin, which means that it fools the body into thinking that it is not time to sleep yet. And children and adults, who uses tablets or mobile phones just before bedtime, may feel that it is hard to fall asleep.

Apple is on the issue, and launched an upgraded version of its operating system including the function Nightshift, where the blue light can be turned off in the evening to minimize this impact. Nothing is bad about it. But, the fact is that it is not the whole truth. Blue light can also make you very tired!

We usually talk about "eye fatigue" where the blue light is a major contributing factor. And tired eyes can lead to muscle tension, headaches, and hence a general state of fatigue.

What is blue light?
Blue light is physically in the spectrum of UV light (which is invisible) and ordinary daylight (which is visible). We are therefore exposed to blue light during the day when we are outdoors. The blue light is necessary for our well being, and we need a daily dose for the body to be able to regulate hormone levels and assimilate vitamins.

But as with everything in life, moderation is key. Today we are in all exposed to higher doses of blue light by modern light sources such as LEDs and through the heavy usage of screens. It is proven that the strong doses of blue light can damage the human eye and cause inflammation of the conjunctiva and cornea among others. That is why ophtalmologists and optometrists recommend both childer and adults to protect their eyes with sunglasses in the summer.

So, why then does the blue light make us tired?
There are no scientific studies that blue light from the screens directly damage the retina, on the other hand, there are studies that show that people who spend a lot of time in front of screens experience dry and irritated eyes. The phenomenon is called eye fatigue. One explanation is that the blue light wavelength is perceived much more intensely in the eye than for example red light. Really strong amounts of blue light, for example in car headlights, even cause blinding.

I am sitting in front of a screen all dat and cannot change that. What should I do?
Screen workers need to have as good an ergonomically designed workplace as possible;

• The easiest way is of course to choose a monitor that has less blue light than others. The monitors from EIZO are certified by TÜV Rheinland, for its low levels of blue lights.
• The ambient light in the room also plays an important part, where the ambient light and the screen lights should be roughly equal. Thus you should not sit in a completely dark room, with a backlit display. Best is to select a screen that automatically controls screen brightness based on the environment.
• Check whether you can adjust the blue light in any way. If the monitor has an eco-mode, that may be preferred. Another way can be to cut down on the brightness of the screen, to reduce the strength of the blue light.
• Change the color contrast towards the redder colors on your screen. At EIZO we have experimented with the color settings of our screens to reduce the color temperature. The aim is to get a color reproduction of wave lengths that fade to red tones and with less bluish tones. Our FlexScan models have a picture mode called "paper mode" where the blue light is reduced to a minimum in order to cause as little eyestrain as possible for those who alter a lot between the screen and physical documents.
• A technology getting more and more recognition is dynamic light. It means allowing the amount of blue light to follow the natural light. There are examples of wards at hospitals in Sweden where dynamic lightning has contributed to healthier and more alert staff. At EIZO, we have dynamic lightning built into our screens. We call the feature circadian dimming. The function exposes you to a minimum of blue light while ensuring that you do not get sleeping problems.

For more information, visit;
http://www.eizoglobal.com/products/flexscan/blue_light_reduction/index.html
http://www.eizoglobal.com/products/flexscan/ev2450/index.html