Me again - lol!
I've accidentally also recently stumbled upon an independent opticians where pretty much everyone working there is also neurodivergent (this is getting to be a theme with me!).
I used to go to Boots and high street chains but this one is a converted house, so it's just like being in someone's living room. They even sometimes give me cake, and always a cup of tea. It's a bit like visiting the Weasley family.
Everyone who works there is over sensitive/over stimulated by lights/noise/sensory shite so they take ages checking you are actually comfortable.
The optician will say, now are you actually comfy in that chair, move around a bit, have a fidget, bloody awful those chairs, hate the things, let me know if you need a breather, it's not especially nice having someone up close like this is it etc and is very patient.
He actually picked up that it was a bit overwhelming for me and, at no extra charge, said he'd have me come in to get the other eye tested on another day as he felt I was getting a "bit tired".
The staff are all very accomodating.
Again, I had to shop around, pay a few visits and talk to staff before I found "the one".
For the hell that is glasses choosing it was worth it alone. I've got the first pair that actually suit me and are "comfortable" thanks to the autstic "bluntness" of the optical assistant. "No. Not those. They look insipid on you." "YES THOSE!!! You look AMAZING!!! Please trust me and don't pick those awful pink ones!"
I've never had so many compliments on my glasses. Or felt so comfortable at the opticians.
So again, shop around, explain how you feel and you might find somewhere you feel comfortable and where they will give you the space you need.