Sure states may have that rule, but it is totally legal to go to a state that does not have the rule, buy some glasses and bring them back. (Or to buy online from a state that does not have the rule).
Neither the FDA nor FTC at the federal level technically require prescriptions for glasses. Indeed, most online glasses shops will simply take you at your word that you have a prescription, presumably because they are located in a state that nominally requires a prescription, but places no requirement on the shops to verify that the customer really does have one.
This is totally different from contacts, where at the federal level, sellers must verify the prescription with the prescriber, except that if 8 business hours have passed since they started trying to contact the prescriber, without hearing back, the prescription is considered verified. (That last is to prevent the prescriber from trying to prevent customer from getting lenses elsewhere by refusing to verify).
Neither the FDA nor FTC at the federal level technically require prescriptions for glasses. Indeed, most online glasses shops will simply take you at your word that you have a prescription, presumably because they are located in a state that nominally requires a prescription, but places no requirement on the shops to verify that the customer really does have one.
This is totally different from contacts, where at the federal level, sellers must verify the prescription with the prescriber, except that if 8 business hours have passed since they started trying to contact the prescriber, without hearing back, the prescription is considered verified. (That last is to prevent the prescriber from trying to prevent customer from getting lenses elsewhere by refusing to verify).