I was in the internet way-back machine and found this ’01 article about choosing the perfect pair of glasses.
Another retailer, Eyewear Online, recommends parasitic shopping: Spend a little shoe-leather looking at shops; when you find a frame you like, make a note of the manufacturer, frame color, and the numbers on the temple arm; then plug that info into the site. But salespeople are hip to this and tend to icily discourage notetaking. Sometimes shops white-out these numbers or replace them with an internal code. Take heart: You can still get the measurements you need with a ruler and a whole lot of moxie. (This page explains how.)