I know two opticians who accidentally fell into their lens grinders, and made spectacles of themselves.

In my area (central Illinois), we say "optometrist" more than "optician".  (I actually can't remember hearing anyone say "optician" here.)

An optician.

Sometimes, "the optical shop," in one specific case: a combined business or practice with several eye doctors and an optician on the same premises. "I need to go to the optical shop" as distinct from the medical office.

In England we go to the optician's. I think it is the same in the USA but it's so long since I lived there (1970s!) I don't remember!

It's the same in the US.