title_body: Are there studies that show whether reading ebooks on e-Ink, LCD, SLCD or AMOLED displays are better for eyes?
upvoted_answer: I don't know about any for those particular screentypes, but LCD vs E-ink has been researched by Siegenthaler, et al.
  
  This study showed that the objective reading behaviour is little different between the two types, but strangely (to me) the subjective preference shifted over time from a small advantage by E-ink to a small advantage by LCD.