Unlike other sleep masks, this patented Lights Out Sleep mask does not flatten against the eyes. Its patented shape does not interrupt the essential REM sleep-Allows free eye movement during sleep and rest cycle.  REM Sleep, characterized by Rapid Eye Movement, is the most crucial part of the sleep cycle. The patented mold of Lights Out dpes not interrupt the essential REM function. 

During sleep, a healthy adult alternates between Non REM and REM sleep. Non REM sleep consists of about 75% of the rest process and REM comprises the remaining 25% of the cycle.

By allowing this freedom of eye movement, the eye mask wearer awakens feeling refreshed and rested- unlike the use of a typical eye mask which flattens the lid against the eye.