One of the best articles I came across that compares the blue light emitted by Kindles compared to Smartphones and iPads. Its an old write-up but shows how Kindles emit less to almost no blue light and answers the question whether an iPad in comparison can achieve the same. A must-read for those confused whether to get a Kindle or an ipad for reading. Booksthreads https://ebookdetectives.com/kindle-paperwhite-have-blue-light/