I'll start by saying I work in the industry and I have actually worked on making blue blocking coatings.
There are two ways these filters work.
The first and older method is to tint the lenses so that they absorb blue light. This will make the the lenses look yellow or orange. The wavelength that is normally targeted is 455nm. The more yellow or orange the lenses look the more blue light they are blocking. This tinting process works the same as it does in a normal sunglass lens (by dipping the lens in a hot water bath that has dyes dissolved in it; the dyes migrate to the porous lens material).
The second method is to put a blue reflective coating on the lenses using vacuum deposition. You can recognize these lenses because they have a strong blue reflection (not to be confused with a subtle blue reflection which can be seen in a normal anti-reflective layer). These lenses won't block as much blue light as the tinted lenses but they look nearly like normal glasses.
I suppose some manufactureres may try a hybrid approach although (both absorption and reflection). Anyway the general thing to think about is that the more "normal" the lenses appear the less blue light they will block.
I never understood their use as computer glasses because all computers and phones have low blue light modes now and these do what they say they do, and I've measured the output of screens with a spectrophotometer.
>So if the research says there isn't enough evidence it's fine, do more researches and find out exactly what happens here, but don't go around and tell how it's all made up and not helping anyone.
I think most of the backlash is against the the claims that blue light is damaging and that these filters will protect your eyes. I think in these cases the evidence has to come first.
https://www.aop.org.uk/ot/industry/high-street/2017/05/26/bo...
Obviously if someone suffers from eyestrain it's great that there are products out there that you can try (on a personal scale it doesn't matter if the solution is placebo or a not yet clearly understood therapy) but this is different from saying that everyone should have these to protect their eyes from the danger of blue light. Personally I use the night mode feature on my devices but I wouldn't bother with the glasses because to me they seem redundant.
Another thing I would like to add is that I've never met anyone technical working in the industry that actually believes these filters work and everyone considers them a marketing led exercise.