D.C. Mun. Regs. tit. 17, § 6416
6416.1 An eyeglass prescription shall expire one (1) year after the issue date unless there is a medical reason that warrants a prescription for less than one (1) year. The medical reasons for issuing a prescription for less than one year shall be documented in the patient's medical record.
SOURCE: Final Rulemaking published at 55 DCR 12043 (November 21, 2008).