> E.g. Obviously a participant can not use their mobile phone or other screen devices if they are wearing a mask, and the mere fact they are wearing the mask may force them to do the one thing they can do: sleep.
This sounds like you describing the mechanism rather than rejecting the idea that a sleep mask helps. IOW, it may help because it "enforces" better sleep hygiene.
This sounds like you describing the mechanism rather than rejecting the idea that a sleep mask helps. IOW, it may help because it "enforces" better sleep hygiene.