Crt monitors were and are known for being bad for your eyes. This is a fact that they produce all kinds of light that is harmful to the eyes
And blue light is also in fluorescent, incandescent light sources. Yes it is in leds but not all. Mike Holmes for example installed led lights in a walkway that produces light that doesn't attract bugs.
@WalterDasTrevas even mentioned fluorescent.
You can buy led lights for a variety of purposes with different light spectrums.
Have you completed your assignment yet?