Originally Posted by HarryT
Rationally speaking, there should be absolutely no difference between reading from an eInk screen or reading from a backlit screen whose brightness is correctly set.
I can only think that people who complain that they can't use backlit screens perhaps have the brightness set too high?
Everything about human-machine interaction is complex, and the complexity mainly comes from the "human" side of interaction. First, every person reacts differently, and second, our eyes have a weird tendency to favour certain lightning conditions. For example, we prefer daylight to most artificial sources of lightning, regardless of the luminosity or the energy delivered in process.
I am not certain what is the exact source of problems with backlit use, it might be something as simple as refresh cycles that we don't really "see", but still can tire our eyes after prolonged use.