>much closer to just having a reading light on
First of all, that contradicts the evidence from my eyes, but second of all, even if it were true, you'd have to persuade me that reading an old-fashion paper book with a reading light is any better at helping me get to sleep at night than reading from an iPad. I'm not buying that one either mainly because a reading light is going to throw more light onto the ceiling, where of course it gets reflected down again, and neuroscientists know (and the Scandinavian tradition "knew" in practice decades ago) that light from the top of the field of vision is more disruptive to sleep than light coming straight into the eye or from the sides or bottom of the visual field.