S.C. Code Ann. § 37-25-40

A prescription for a contact lens without power sold for any reason is valid for twelve months from the later of the date: (i) the prescription is authorized; or (ii) the last date of the contact lens evaluation by an optometrist licensed in accordance with Chapter 37, Title 40 or ophthalmologist licensed in accordance with Chapter 47, Title 40. A contact lens prescription may not be issued to expire beyond this twelve-month period and may be only issued to expire before the end of this twelve-month period if the expiration is ordered due to a health related reason noted in the patient's medical chart.