Are contoured 3D cup sleep masks better than flat masks?

Across the reviewers we read, contoured cup designs are strongly preferred for two specific reasons: they create true blackout at the nose bridge and they leave space for eyelashes and REM eye movement. Verified-purchase reviewers and specialist subreddits like r/sleep consistently note that flat masks press on the eyelids and tend to leak light. Flat or silk masks still have a place for travelers who prioritize packability over total darkness.