Originally Posted by Matriarch
Not quite. With a backlit screen, the light is being cast directly up into your eyes, so it's the angle of the light that fatigues some eyes more than the fact that there is light. With a frontlit screen, such as the Paperwhite that the OP is getting, you're looking at a light source still, but the angle of the light is entirely different - it shines away from your eyes. This provides a fundamental difference and vastly reduces eyestrain. It's really a remarkable technology.
If it really shined away from your eyes you wouldn't see it at all. The only real difference between edgelit and backlit is the light is less intense for edgelit because of the size of the light source and the need to travel through fewer layers. Angle has nothing to do with it. The light still gets bent and reflected to an angle that is direct to the eye.