Recently, there has been a rumor circulating on the Internet that "the blue light emitted by mobile phones is very hurtful to the eyes". Whenever we watch TV, mobile phones, and pads for a long time, our eyes are particularly tired. Is this caused by blue light?
In order to solve everyone's confusion, we connected with Wang Kai, deputy chief physician of the Department of Ophthalmology of Peking University People's Hospital, to answer for us.
Blue light, the phone's much weaker than the outdoors
Wang Kai said that in fact, not only blue light, in fact, visible light reaches a certain level, it will also cause damage to the eyes. The reason why blue light is particularly emphasized is because the wavelength of blue light is relatively short, so the energy of a single photon will be higher, and the damage to the retina will be stronger than that of red and green light. But in fact, if it does not reach a certain amount, it will not cause damage, mobile phones, computers emit blue light is actually much weaker than the natural outdoors, and now mobile phones, monitors are tested and certified, generally there is no problem.
Eye fatigue is more due to the distance
So, why do you feel particularly tired after using mobile phones and computers for a long time? Wang Kai explained that many people look at the mobile phone for a long time, they feel very uncomfortable, in fact, it is mainly because the distance between the eyes and the screen is too close, when we are too close to the display, the ciliary muscle will contract, and it will feel particularly tired after a long time.
Therefore, when we look at the screen, the distance is 30 cm - 40 cm is better, but in fact, there are very few people who can use the standard distance to see the screen, for many reasons, such as the short arm of the child, when holding the mobile phone can not reach the standard distance.
Using mobile phones is more harmful to children than adults
Wang Kai pointed out that the harm of blue light to children's eyes still needs further research to confirm, but any light that reaches a certain degree will be harmful to children's eyes, but as long as it does not exceed this degree, it is generally fine.
When children play mobile phones and pads, too close to the screen is very damaging to the eyes. Because most of the children are farsighted when they are born, so he needs to use more regulation than adults to see the words of the mobile phone, if you let the child observe close objects for a long time, it will accelerate the process of eyeball facing, which will induce myopia prematurely, but blue light is not a big problem. (This article was interviewed by myself and first published in NetEase Health in 2015)