15 U.S.C. § 7604: Expiration of contact lens prescriptions

on the date specified by the law of the State in which the prescription was written, if that date is one year or more after the issue date of the prescription; not less than one year after the issue date of the prescription if such State law specifies no date or a date that is less than one year after the issue date of the prescription; or notwithstanding paragraphs (1) and (2), on the date specified by the prescriber, if that date is based on the medical judgment of the prescriber with respect to the ocular health of the patient. If a prescription expires in less than 1 year, the reasons for the judgment referred to in subsection (a)(3) shall be documented in the patient’s medical record. In no circumstance shall the prescription expiration date be less than the period of time recommended by the prescriber for a reexamination of the patient that is medically necessary. As used in this section, the term “issue date” means the date on which the patient receives a copy of the prescription.