Originally Posted by ChrisAtlanta
I, for one, cannot sleep with an eyemask on, and I'm sure I'm not the only one. It's also very disturbing on an eastbound overnight flight if they're not all down, and the sun starts rising.
Also, eyeshades are not 100% effective - it is still darker under them when the cabin is dark than when it's flooded with light.
One more thing: A dark cabin tends to be a quiet cabin. Once the cabin is full of light, then it gets noisy very fast. That disturbs everyone who's sleeping, too.
Overnight trans-atlantics are quite short enough without the sun rising halfway through the flight. We all struggle to get enough sleep as it is, so that we can function to some extent the next day.