An optician is a person who makes and sells eyeglasses and contact lenses. They can also perform eye examinations to check for vision problems.
In German, "Optiker" refers to both the profession and the person who practices it.
For example, you might say:
* "Ich gehe zum Optiker, um neue Brillen zu kaufen." (I'm going to the optician to buy new glasses.)
* "Der Optiker hat mir neue Kontaktlinsen angepasst." (The optician fitted me with new contact lenses.)