Ok, so I have hit my self a number of times in the head/face with a yoyo… but I’ve also walked face first into an open door.
I haven’t smacked myself with a metal throw yet, but can confidently say that a plastic full force to the face will just knock glasses out of wack. They really are a lot more durable than you think, chances are the frames are more likely to break than the lens if you give them a beating.