Melatonin is inhibited by light reaching the eyes. An eye mask might be enough. Speaking with regard to sleep, not cancer, I have to block any LEDs on things like battery chargers to sleep well. I despise the trend of putting blue power indicators on things used at night (I'm looking at you, Air-O-Swiss).
So do I, the blue LED is the curse of the modern era. Old time red led's have zero annoyance for me but when I walk through the living room at night and it's all alight in blue glow from the dvr etc it annoys me on a visceral level.
Thick black electrical tape is the best fix unfortunately.
> I despise the trend of putting blue power indicators
Blue indicators should be deemed illegal. I had a laptop that had no less than 14 (fourteen) blue light sources on it. I had to unscrew the part and remove the LEDs.