So this is something I've been thinking about. The Foreigner books talk about how atevi have better vision than humans, particularly in dim or dark environments, but they've also mentioned that humans do have the advantage of better vision in very bright conditions, like midday in very clear and sunny weather, but that that just doesn't come up in a way that helps them as often because it's such a specific circumstance. Another thing is that the atevi solar system is described as being particularly "dusty" and full of space debris, resulting if far fewer stars abd constellations being visible than we have on our Earth. I'm not sure what all of the scientific details might be about that concept, but it seems reasonable to assume that if it can, canonically, block out the light of most stars, then it might, perhaps aided by other factors like, idk, the composition of the upper atmosphere maybe, be able to a reduce the brightness of the light they get from their sun. The atevi, having evolved on this planet and adapted to its conditions, would then be better adjusted to its typical light levels than the humans, who have adapted to the lighting on our Earth and might more frequently find that conditions on EotA are a little too dark for them. In other words, the atevi vision thing might be more of a "home field advantage" for them rather than inherently better vision. (This would, of course, probably mean that some artificial human spaces, like on the ship, might tend to be too bright for atevi comfort, which hasn't been mentioned directly but which I think is compatible with the general idea we see of human spaces tending to be visually unpleasant for them, right? The space isn't kabiu, the numbers and colors and whatnot are wrong, so might the lighting be.)