The dog ate my wife's $250 prescription lenses, so she wore her $40 backup pair from Zenni to her eye exam.

After a shitload of "oh, these aren't our lenses", they reluctantly put the glasses in their refractometer. The Zenni lenses matched the prescription perfectly.

I bought a pair of Zennis in 2013. I have a strong prescription and got maxed out UV, indexing, etc. on a (imo) good-looking frame. $75 for what would have cost me $300-400 out of pocket after my vision insurance credit. Additionally, I was able to submit the $75 as an out-of-network expense. It took some paperwork, but the return on my time was worthwhile.

Salesguy comes in wearing sharp titanium semi-rimless glasses. Notices that I'm wearing very similar. We compare.

His cost $350. Mine cost $35 including shipping. I bought a backup pair, too.

THIS. Before Lasik, I was all about the Zenni Optical.

I'm sure some people have had very good experience with zenni, but for what it's worth I gave up after 4 pairs (over about 3 years) that never quite had the right prescription. I had better luck with Warby Parker, but only have a single pair for comparison.