As someone with eye damage, I can tell you from my personal experience that a regular ereader with a good light is less stressful on the eye than a lighted unit in the same lighting. I used my Mom's paperwhite for 3 months before I gave it to her for her birthday (she's resistant to new technologies and I wanted to make sure it worked
). I could not read as long with the paperwhite as my other ereaders (both kindle and nook). That said, it was marvelous when reading at the doctor's office waiting room or other places with iffy lighting. My experiment basically says that it is up to you. If you read in places other than your reading chair, the lighted units are a huge benefit. I can't even read in some places without it. But my reading chair is well lit and of course, my damaged eyes showed that it is slightly more stressful on the eyes to have that backlighting.