There are no e-ink devices with backlights. It doesn’t make sense for the technology, which is purely reflective.

There are plenty of e-ink devices (like Kindles) that have frontlights. Even better are the ones that adjust frontlights based on ambient room lighting. Ambient light adjustment (and lighting warmth adjustment) is what the new Kindle Paperwhite has.

LED backlights have been available in ereaders from Amazon, Kobo, and others for a while now. The first kindle paperwhite with LED backlights came out in 2012.

So in some sense do eReaders with backlights defeat the whole purpose (i.e. increase eye strain back to normal display levels)?