I would think the legality of working on glasses frames varies from
state to state and dates back quite a few years to when the science
of correcting vision was in its infancy, and jewelry stores had an
optical department. As it was explained to me here in Georgia, as
the science of correcting vision and making corrective lenses
developed, and opticians started becoming licensed to practice, the
opticians wanted to guard their “territory” and lobbied state
governments to make laws prohibiting anyone other than licensed
opticians or anyone “under their supervision” to work on glasses
frames. Any store that had optical departments were grandfathered in
and allowed to continue working on glasses frames, but they gradually
faded out due to the old timers retiring, etc. Now days the law is
rarely enforced here, but I can understand the justification for such
a law. Note a previous posting of making a mistake involving a pair
of repaired glasses - no offense, just citing an example. In the
jewelry repair business there are butchers and wannabes, and there
are accomplished bench mechanics and it’s sometimes quite difficult
to tell the difference until it’s too late. If I were someone
needing a repair, I wouldn’t want just anybody to work on my glasses.
I would like to be assured they know what they are doing instead of
giving me back a pair of something that was used as a training exercise.