A contact lens prescription is an authorization for a regulated medical device, listing your vision correction numbers. Since contact lenses sit directly on the eye, their use requires professional oversight to ensure continued safety and proper fit. This article clarifies the standard duration of a contact lens prescription and explains the health and legal reasons behind its expiration.
The Standard Prescription Duration
The typical lifespan of a contact lens prescription is determined by federal and state regulations, generally lasting for a minimum of one year. This minimum duration is established by the Fairness to Contact Lens Consumers Act (FCLCA), a federal law governing the release and expiration of prescriptions. The FCLCA requires that the prescription remains valid for at least twelve months following the eye examination and fitting.
While federal law sets the one-year minimum, some states have enacted legislation that extends this period, making a prescription valid for up to two years. An eye care professional is permitted to set a shorter expiration date only if there is a documented medical reason related to the patient’s ocular health. The expiration date is calculated from the date the patient receives a copy of the finalized prescription following the examination and fitting.
Medical Necessity for Expiration
The requirement for regular renewal is a public health measure designed to protect the eyes from long-term damage. Contact lenses are classified by the Food and Drug Administration (FDA) as medical devices, making regular professional checks necessary. The expiration date forces a mandatory re-examination to physically assess the ongoing health of the cornea and surrounding tissues.
Wearing lenses with an outdated prescription can lead to complications even if the wearer perceives their vision is stable. An improperly fitting lens can cause corneal abrasions or deprive the eye of sufficient oxygen (hypoxia). Chronic oxygen deprivation can trigger corneal neovascularization, where abnormal blood vessels grow into the cornea, potentially impairing vision. An expired prescription also risks serious eye infections, such as keratitis, which can occur if the fit is slightly off or lens material degrades.
Practical Implications of an Expired Prescription
Once the expiration date passes, the prescription is no longer legally valid for purchasing new contact lenses. Retailers, including those operating online or in physical stores, are prohibited by law from filling orders for an expired prescription. This restriction is a direct consequence of the FCLCA, which mandates that sellers must verify the prescription’s validity before dispensing the device.
To renew an expired prescription, the patient must schedule a comprehensive eye examination that includes a contact lens fitting. The eye exam determines the correct refractive power, while the fitting ensures the lenses have the correct physical parameters, such as the base curve and diameter. This fitting check confirms that the lens material and design are suitable for the eye’s shape and health, ensuring optimal comfort and oxygen flow before a new prescription is issued.