when relatively complex.
The charges for frames at optometrists are particularly egregious. A very small qualtity of good quality plastic and/or metal, mass produced.
When you look at the complexity of a cellpone, or a handheld VHF, and you can buy that for mid range optometrists glasses, you get an idea of the optometrist (and his supplier) markup.
Blye's prices is particularly low
I will try them.