Short answer: Confirm which eye doctors and optical retailers are in network, since allowances and copays are richest in network; out-of-network care is reimbursed on a lower fixed schedule. Large chains and independent providers may be treated differently.
Vision plans deliver their best value in network; full exam copays and the strongest frame/contact allowances apply only to participating providers, while out-of-network visits get a smaller fixed reimbursement. Networks also vary in which retail chains and independent optometrists participate, so a plan that’s great at one store may be weaker at another. Before choosing, check that your preferred eye doctor and eyewear retailer are in the plan’s network.