Metalenses are a relatively fringe optical technology — at least, they were. Until now, it has been largely pursued by startups and scientists but that is changing as Canon has jumped into the fray and not only makes them but also produces the equipment necessary to manufacture them.
Mainly it’s number of lenses.
High quality camera lenses have like 10-20 lenses, while glasses have … 1
Sir, that’s called a monocle.