[Nomentatus]

I might mention that, believe it or don't - a living skull is translucent, and our brains can detect light all by themselves. So a mask is good, but not nec a whole solution.

In old experiments, just the light coming in under a door diminished melatonin in mice.

[nerdponx]

The skull itself? That seems implausible. Something on the skin other than the eyes seems more likely.