[Ripplinger]

I know that with the Kobo Glo you can completely shut the light off. Not just down to a lower level, it has an on/off button. I'm pretty certain the Kobo Aura and Aura HD are the same way, a button to completely turn off the light. I also can turn the light down to a minimal amount, so it's much easier on my eyes than trying to read from any backlit screen such as a tablet or a phone.