Building on a concept and concern of ghosting started by Dr Don in
this thread, I can easily say that after almost two (2) years of use that the bottom status bar line has burned in/ghosted so that it is easily seen as a black band at the bottom of the screen. It never impacts the use of the device and I only notice it in the brief time I look at the screen as I turn the unit on. (And yes, it does return the favor.*

)
What I have noticed lately is that the screen will fade (lose contrast) if left on and ignored for perhaps 30 minutes. (Sometimes clients will call when I am reading and I will put the reader aside and pick it up after the call.) If I hit page back and page forward the contrast is as sharp as it was one day one.
I set the reader aside tonight and checked on it every ten (10) minutes and it started at about 20 minutes and seemed to get a bit worse at each observation. (And that is a highly subjective judgment.)
Has anyone else noticed this? Are my eyes going bad? Has my brain melted? (again)
(* = Joke based on US car commercial.)