@ossobuco,
As it happens, I just recently ordered some glasses from Zenni for sozlet, on DrewDad's recommendation (but before the exchange here...! Just a coincidence timing-wise). Her eyesight has gotten worse again and her current glasses aren't working for her anymore.
I'd wanted her to have a pair of backup glasses since she's a kid and it's highly likely that she would lose or break her glasses at some point, and the place that takes insurance takes about two weeks to make new ones. The total to get new lenses in her current frames and a new backup pair of glasses at our eye place (with insurance discounts included) came to about $500! And that's not counting contacts, which she's interested in for sports.
So ended up buying the backup glasses from Zenni ($35 total with shipping etc.), then when those arrive we'll take her current glasses in to get replacement lenses, and insurance will take a big chunk out of that. So $500 to maybe $100 total for the two pairs of glasses (main and backup). Much better.
Anyway, all that's just an aside re: glasses in general and Zenni in particular, will report here when they arrive. Good luck with the trifocals, osso.