It says on the internet that they are made in Italy and Japan

is this a glass lens?

I think it is, I’m a sunglass fan, these are the best lens, my gal friend stole them from me, her previous fav Chanel

Can you wear your prescription glasses underneath large Serengeti

No, there is no additional space for prescription glasses.

Interested in the Summit with Sedona bi-mirror lens. Will these fit large faces/heads comfortably?

I’m not sure but I my husband is loving them and they stay on his head , which is usually a problem with every pair of sunglasses he has ever bought. They fall off his head when he bends over and then a lens breaks. So far they have not fallen off his head once. My husband is a slender man though and his head is not that large so I’m not sure if they would be comfortable on a larger head but they seem to curve from the temple to the behind the ear so that both the arms are hugging your head so to speak. They are worth checking out as long as you don’t scratch them up I’m sure they are returnable.