American neurologist Tarek Yousef in an interview with The Conversation spoke about the nature of the large-scale belief associated with blue light. Today, there are many glasses on sale that block light waves at this length, and smartphones use filters that reduce the brightness of blue in favor of red. All this is supposedly done to make it easier for people to fall asleep (blue light is believed to negatively affect the natural rhythm of sleep), but in practice this does not work.
Tarek Youssef explains that it all started with the discovery of the melanopsin molecule, which is associated with a group of neurons in the eye, signals from which go to the suprachiasmatic nucleus. This is our "biological clock", here the regulation of circadian rhythms takes place, on which the quality and duration of sleep depends. It is known that as a photopigment, melanopsin is most sensitive to blue light, which led to a dubious conclusion. Namely, the constant presence of blue light from screens and monitors in front of the eyes affects the brain and sleep-wake cycles.
There are many more adherents of this theory among businessmen and designers than among scientists. The theory is simple and straightforward to raise blue light blocking to the level of an effective drug that can be sold. But no clinical trials have ever been conducted to support these claims. But there are measurement results, according to which melanopsin reacts to many shades of light, just the level of reaction is weaker than to blue light. So what should be blocked then?
Tarek Yousef is inclined to think that the matter is not limited to one light, our brain receives a huge number of different signals, on which the circadian rhythms of the body ultimately depend. For example, elementary fatigue of the eyes, which did not blink for a long time, because the person was enthusiastically staring at the gadget screen. So what does the blue light have to do with it?