I've had a good friend bounce a 9mm brass casing off a barrier to land between his glasses and eyeball. I think we were up at TMGN. He's a member here on MDS. It burnt part of the surface and looked hazy white. He went to the ER, got some cream/drops or something and it got better eventually. Another reason why you shouldn't wear regular (small) prescription glasses at the range. Get real safety glasses.