obviously not!
Well, I could be flip and leave it at that, but as near as I can tell, I was looking down at the time, and the glasses were probably a little bit forward and the branch slapped back from above and came above the glasses.
This isn't the first time a branch has got me in the eye, in spite of glasses, but it has been a few years since one gave me a really good whack.
I've scratched my cornea twice while orienteering despite wearing glasses. I'm looking into prescription sports glasses for more protection.