California Code, Business and Professions Code - BPC § 2564.76

(a) Ophthalmic lenses may be sold only upon receipt of a written prescription or a copy of a written prescription and may be sold in quantities consistent with the prescription's established expiration date and the standard packaging of the manufacturer or vendor. If the written prescription or a copy of it is not available to the dispenser, the dispenser shall confirm the prescription by direct communication with the prescriber or the prescriber's authorized agent before furnishing, shipping, mailing, or delivering any lens, and maintain a record of the communication. A prescription shall be deemed confirmed upon the occurrence of one of the following:

(b) If a prescriber communicates with a dispenser before the time period described in paragraph (2) of subdivision (a) elapses and informs the dispenser that the ophthalmic lens prescription is invalid, the dispenser shall not fill the prescription. The prescriber shall specify in the communication with the dispenser the basis for invalidating the prescription.

(c) A dispenser shall not alter any of the specifications of an ophthalmic lens prescription, other than the color, or substitute a different manufacturer, brand, or other physical property of the lens.

(d) Notwithstanding the provisions of this section, if the ophthalmic lens is manufactured by a company, but sold under multiple private labels by that same company to individual providers, the dispenser may fill the prescription with an ophthalmic lens manufactured by that company if the ophthalmic lens prescription and the related parameters are not substituted, changed, or altered for a different manufacturer or brand.