I've been buying glasses from Zenni online for awhile. Here's some things I've learned.
1-It's easier than you'd think to be informed about your prescription and get what you want in eyewear.
2- Get an eye exam from an Ophthalmologist not an Optometrist. Around here the exam price is the same but Optometrists sell glasses and they may not want to help you get the same thing they sell WAY cheaper.
3- Most important, the tech person at my Ophthalmologists office was more than happy to answer my detailed questions about lenses for ordering online. With the tech's help I could sort out the sales and marketing from the facts.
I've been very happy with Zenni's quality. The first pair I ever ordered were bifocals and it was an aha moment. They fit my head just right and I could see better right away. As good or better than all the local shops I got glasses at over the years at a fraction of the cost. One pair of RX sunglasses from Zenni didn't work out, but they were only $22 so I didn't bother to return them.
Recently I went back to 2 local eyewear shops. I was going to try progressive lenses again after being very disappointed in the pair I got locally 18 years ago. I was thinking with progressives I may need the help of a local shop and was willing to pay more for them. One shop was very good at quoting prices, but couldn't tell me what exact brand or material the lenses would be. The other is good on details and OK on price. Most of my questions were unanswered by the local shops. So I went back to Zenni.
I just ordered a pair of digital free form progressive lenses and a pair of bifocals in the exact same frame from Zenni. It's the same frame I've worn for 2 years with my old RX so I can test them all side by side. The total for both pairs is 1/5 the cost of a pair of basic progressives locally and Zenni has a better refund policy.
I have no connection to Zenni other than being a satisfied customer. I'm happy to share my experience if anyone has questions.