To add to this, I have a strong prescription requiring kinda special lenses to not be crazy thick, and even with that I got a really expensive frame with the special treatment for ~$150.

In France, the "not 2-inch thick" lenses alone end up costing that, with me ending up paying over $300 + the habitual 2 month waiting period just to go to the optometrist...

So even if you have some special needs, they'll often be able to accommodate (though sometimes you need to wait a day so it won't be same day)