These prices are very similar to those in Bangkok.
Titanium frames are light and durable but very expensive here too.
I used to drop my glasses and broke one of the lenses, so I had to get a replacement lens. Sometimes I changed the lenses into darker colours for driving! You could always change your lenses if they no longer work for you! I always bargain to get more reduction! The frames are have a mark up of three to five times the original cost!
Hope you could find a nice optician.