[notliketherest]

That's because the insurance companies can negotiate steep discounts from eye glass providers, given they have so many members and choose what eye glass providers they can buy from "in network". So the eye glass providers up their prices so that 25% discount from last year takes a smaller bite out of their profit margins. Rinse and repeat for 40 years and you'll get what has already happened to the health insurance market place: $800 for a pair of Advil "base price". Insurance companies get a huge discount. Non insured individuals are shit out of luck (though the providers normally waive a substantial percentage of cost for the neediest patients.)