I have a complicated prescription, my husband has a very complicated prescription. His company for a while, made them order their prescription safety glasses from an on line retailer. He tried but never could get the focus correct. Our optometrist had to help him get the correct numbers and those worked, sort of.
For us, we would never order glasses on line. I used to get mine at a local place that specializes in high index glasses. One time when the kids were young, we tried for a cheaper option. But it was money wasted because they didn’t work and we got terrible headaches.
I think you get what you pay for but I am extremely particular with my eyesight.