GoaWish.......I have bought frames in Goa and had lenses fitted in the UK, it was a long time ago though but it worked out okay for me. I found that the Goan optician's couldn't get the very thin lenses that I wanted so I bought them here and had them fitted into the Goan frames.
What MazD says is also true, I bought frames over in Goa that were very similarly shaped to ones purchased in the UK so that I knew that I could get lenses to fit the frame without reducing the magnified field of vision. (Sorry can't explain it better than that). I know that some frames are better suited to particular lenses than others; for instance, I wanted the very lightweight flexi unbreakable frames (because of my job) but I couldn't have them as my particular lenses would not have fitted.
If anyone can explain this better - please do
Fizz