My impression is that VSP was formed by a bunch of overpriced small opticians to try to keep high pricing.
The VSP site touts staying with VSP-approved opticians. But I've found their prices, AFTER applying the VSP benefits, to be much higher than prices from equally-good mass merchandisers even without VSP benefits.
If you're forced to have a VSP plan, then buy outside their network and make a claim on VSP yourself, and you come out far ahead.
Example: Frame and progressive no-line bifocals in polycarbonate.
1. From Internet provider, and from Visionworks and from Optical Outlet:
$140, of which VSP will pay $140. Nothing to pay out-of-pocket.
2. From VSP-approved optician:
$400, or $320 with VSP discount, of which VSP will pay $150, leaving you $170 to pay out-of-pocket.
The Internet provider sold a much better product - even flex titanium frames. The Visionworks product was the same, and the Optical Outlet very slightly inferior.