"Let me explain. No, there is too much. Let me sum up."
1. There is no scientific proof or extensive testing that shows any difference in terms of eye strain due to display type, whether it is e-Ink, LCD, OLED, backlit, sidelit, or a sticker stuck on the front of the device
2. There is plenty of anecdotal/personal experiences from users preferring one type over the other. Some just cannot use one type at all without pain, others can for many hours at a time.
3. You really need to try them yourself to decide what is best for how you read.