Here's one more anecdote: I'm using the computer the whole time. I make the screens usually more bluish than redish as I don't like everything in orange tones.

Here's one more anecdote: I'm using the computer the whole time. I make the screens usually more bluish than redish as I don't like everything in orange tones. I prefer bluish-grays. I'm staring at the screen until late at night, more or less until just before going to sleep. I've never experienced any bad side effects form that. When I'm tired I can always sleep instantly. Funny enough I don't like bluish light besides on computer screens. All my lights are dimmed, and I prefer them being kind of orange. Actually my eyes hurt when being in places that use bright cold lights. That makes the contrast (especially at night) between my computer screens and the ambient light quite significant. The screens seem the brightest lights in the room. Even they are also dimmed. For the matter at hand I think there's one important observation to make: Most screens are just way too bright in default settings!¹ I usually dim screens to at least ~50%; when it's a bright one even down to ~30%. Not only that my eyes start to hurt after a short time looking at a screen in factory settings I get every time even severe headache after some hours looking at such a thing. Most people I know don't dim screens. They like it as bright a possible as it makes the color experience best (and you don't need to dim the light in the room to be able to see something on the screen–especially during day and when there is sunshine around). The screen manufacturers also picked that up: Every new screen has an even more extreme maximal brightness than the previous models. It seems to be the "loudness war" of screen manufacturers. A screen with warmer colors is less bright than a screen with cold colors (as the screens usually don't adjust brightness at the same time when fiddling with the colors). The back-light of a screen has a quite extreme cold color so making the screen more warm filters more of the back-light and makes the screen less bright as a result. So if I would have to guess why some people experience positive effects from "redshift"-tools I would bet the effect is actually only related to screen brightness and has nothing to do with the color as such. Whoever came up with this "redshift" theory was overthinking things, imho: It's true that the natural light gets more warm in the evening (as it is also in the morning… ;-)). But it gets also darker when night comes! That's actually the significant phenomenon in my opinion. ¹ Just try to look for some time into a 160W light-bulb… Try also a 40W model instead.