I get headaches from zenni as well as other online glasses stores. The local Jewish stores have a better quality lense.
Most likely has to do with the prescription rather than the quality of the lens. I’ve gotten glasses from several online companies and my vision was crystal clear with no issues.
The quality of the frames is inferior to name brands, but for the price it’s definitely worth it.
I have always wondered how they are able to do it at such a low cost. I understand that they can get a frame for pennies, but what about the lenses? Those can’t be mass-produced.