Well yes my friend, you always hear about it but you don't necessarily understand. " Blue light doesn't mean anything, our screens aren't 100% blue, there are plenty of other colors and I'm in HDR " blablabla. Long story short, blue light is one of the naturally occurring colors in the daylight spectrum . But like many other things, humans have managed to artificially recreate it: it is used in our screens and we are therefore exposed to it almost all the time.