IPA: /ɒpˈtɪʃən/
KK: /ɑpˈtɪʃən/
A professional who makes, sells, or fits glasses and contact lenses to help people see better.
I need to visit the optician to get my glasses adjusted.
Optician → It is formed from "opticus" (from Greek "optikos", meaning of or relating to sight) and "-ian" (meaning a person who). An optician is a person who specializes in sight-related services, particularly in the fitting and dispensing of eyeglasses and contact lenses.
Think of someone who is an expert in things related to 'sight' ('opticus') — that's why an optician helps you with your vision.