I've been staring at a screen for decades, but only fairly recently found out about the harm of blue light, and am using f.lux with the "soft light" effect.
Aside from blue light, is it bad for your eyes just because of the brightness level? Is there any kind of objective measure of how bright is "safe"? And if so, is there any way of knowing how many nits a monitor is emitting?
AIUI the problem is mostly the blue light. I can't imagine that becoming habituated to staring at a bright light is all that good either, but I don't know of any specific studies on that. It's also the kind of thing that only shows up statistically after twenty years, as a higher incidence of inability for the eye to accommodate to lower light levels etc. Nobody's going to look at a too-bright screen for a day or two and immediately notice a drastic difference.