Modern life is all about innovating our way out of our inabilities. We're not meant to be awake when the sun don't shine. If we've mastered anything, it's light. For the large part, this is good news; extra hours in the 'day' mean we can socialize longer and get more work done.
Trouble is, evolution has programmed the human body to equate light with wakefulness. Our eyes treat blue-heavy light - like the soft glow of an iPad - like the midday sun. So until we evolve beyond a light-regulated circadian sleep/wake rhythm we need to accept the relationship between light and sleep, and understand what we can do to help it along.