Sunglasses sometimes have mirrors to look at other people behind one, for example, but never enough mirrors to look at oneself. These sunglasses would have mirrors on the interior of the lenses, so women could put them on and confirm or deny how their makeup looks.
It is likely there would need to
be a low light interior lighting system.
These are most useful for women who need affirmation after viewing a romcom at the cinema and the attendant emotions.