I just tell my DR I need the PD for work, as they provide me with a pair of prescription safety glasses every two years. They don't, but it's easier than arguing.

A friend of mine used to be an optician. He told me that the materials cost for most any pair of eyeglasses is around $15. Everything else is brand name licensing, labor (he got paid $20/hr and took about 30 minutes to cut lenses and put in a frame) and store profit.

I've yet to order from Zenni, was wondering why the low opinion of their quality.