SemiRimless Frame Material

Lenscrafters is telling me that with my prescription (OD -7.50
OS -9.00) that they don't recommend semirimless frames because
of durability, they tell me that the rimless bottom half is held
up by a nylon string that wouldn't last with such thick glasses.
Now, I've seen coke bottle lenses in semirimless frames that looked
to me like there was a flat metal wire in the groove at the bottom
of the lenses, and these glasses were quite durable, so my question
is, does this flat metal wire design have a name so I can ask for it?


Thanks.


Sue