Optician in German is "Optiker" or "Augenoptiker" (Auge = eye).
The signs outside the shop normally have the word "Optik" on them.
go to an optician, you may need your eyes tested
I assume you mean spectacles? In which case, you must first have your eyes tested, and the Optician will have your spectacles made to your prescription.
An optician works with the eyes. An obstetrician would be the doctor who would deliver a baby.
By having bad eyes.
Anything related to your eyes is best initially checked by a qualified optician. Once your eyes have been checked, the optician may then refer you to a specialist in a hospital, or to your general doctor for treatment.
Is an optician