Can looking at green really protect your eyesight? I have been deceived for many years...

When it comes to the color that protects eyesight, I believe many people will answer green without hesitation. But in fact, this color has nothing to do with eye protection, and everyone has misunderstood it!

Before explaining this misunderstanding, we must first understand why the eyes get tired. Eye fatigue is actually the fatigue of your ciliary muscles. In order for our eyes to allow objects of different distances to be refracted by the lens and finally accurately form images on the retina, the ciliary muscles relax when you look far away and contract when you look close. This principle is similar to adjusting the focal length of the camera when we take pictures. When we read books, play with mobile phones, and use computers, we have to keep the ciliary muscles in a highly tense contracted state. After a long time, do you think it will not get tired? In this case, green plants placed nearby and the fresh green on the full screen will not relax the eyes.

So how did the green eye protection misunderstanding come about? This has to do with why green is in the middle of the rainbow of red, orange, yellow, green, blue, indigo and violet.

The wavelength of green light is between 500-570nm, which is the C color in the visible spectrum. It is in the color frequency range that the human eye is most sensitive to, and is easier to be seen by people, so we feel very comfortable. In addition, color psychology believes that when people see green, they tend to naturally think of flowers and plants, which makes people feel comfortable and calm. Therefore, green eye protection is a psychological factor at work.

Of course, if you are too busy with work and study to look into the distance and relax your ciliary muscles, then we can also adjust our sitting posture, the angle and height of the display screen, and adjust the screen brightness. Most electronic devices now can automatically adjust according to the rising and setting of the sun, making the screen less glaring. However, none of the above methods is as practical as letting the ciliary muscles rest directly, so the most important thing and what we need to do first is to strictly control the time and distance of eye use, develop good eye habits, and let the ciliary muscles relax properly to better protect vision.

This article is a work supported by Science Popularization China Starry Sky Project

Author: Duan Yulong

Reviewer: Jiang Yang (Deputy Chief Physician of Ophthalmology, Peking Union Medical College Hospital)

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.