youtube link, psa regarding retailers of eyeglasses, CBC Marketplace
CBC Marketplace is a pretty decent series
apparently retailers of eyeglasses have started to fearmonger regarding blue light [blue light can cause sleep cycle disruption but that's about it, and that can be resolved using computer software like redshift, cf.lumen, or f.lux, which is even mentioned in the video] in order to scam people into buying more expensive lenses.
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