Not just in the US. For example there's a huge glasses cartel in France with specialists that are protected by the government and make pairs of glasses cost 500~1000 USD with very little reimbursement, while in Japan private companies (that actually compete against each other's) let you have glasses for 60~70 USD all included. You are literally better off flying to Japan from France to shop for eyewear.
I spent about a week in Japan, split between Tokyo and Nagasaki, and had no problem, having not even tried to learn any Japanese, except that I couldn't get the right train stop because I couldn't even recognize the characters, much less read them.
The US has a lot of immigrants, so I wouldn't count it as a country with a low percentage of bilinguals.
0- https://www.pewresearch.org/fact-tank/2020/08/20/key-finding...
I'm not sure what you'd do about the eye chart. I don't know about optometry but I would imagine you can't just print off a poster of an English-language eye chart and use that, I always figured they'd be calibrated for a certain size, resolution, and the distance from the vision test machine taken into account.
As you suggest, given the number of western tourists to Japan I'm sure there'd be some subset of optometrists who are set up for English-language patients.
It's between 50 and 250 euros, depending on the brand.
For a pair of Prada or Louis Vuitton sunglasses you can easily spend 350-500 euros, but luxury brands are expensive by definition.
Anyway you pay for glasses and lenses once and then you're good for years.