Comment by throwanem

It might simply be because you've never put concern toward basic lighting theory. Within a basically moderate range of illumination, you get eyestrain not from bright or dark but from repeatedly forcing your eyes to reaccommodate between the two. Adjust your room lighting such that whatever sits behind your displays is about as bright as they are, and dark mode becomes the accommodation problem, while dark on light is as comfortable as reading. Too, in this configuration you can also see things that don't emit light...