I think I was with VSP when I bought replacement lenses in South Korea. (This was about a decade ago.) I sent in the receipt to get reimbursed the $30-$40 for the lenses and then never heard back. My guess is that didn't like the Korean receipt, but since the $ amount was low, I didn't bother following up with them.

That was what I liked about South Korea. Really inexpensive for same day service on a thin lens (I have a -10.50 Rx, so thin is important.)