A contact lens exam is a specialized medical assessment that goes beyond a standard vision test for glasses. This evaluation focuses specifically on how a contact lens, which is a medical device, interacts with the delicate tissues of your eye. The process ensures that wearing lenses remains a safe and healthy method of vision correction. Placing any material directly on the cornea introduces risks not present with eyeglasses, making this evaluation necessary to maintain eye health.
Standard Requirement and Prescription Expiration
The frequency of needing a contact lens exam is primarily dictated by law and the expiration of your prescription. In the United States, the federal Fairness to Contact Lens Consumers Act (FCLCA) establishes a minimum validity period for a contact lens prescription of one year. This means that in most jurisdictions, you must undergo a new contact lens evaluation every twelve months to renew your prescription.
This annual renewal is a legal requirement to purchase new lenses. Contact lenses are classified as medical devices by the Food and Drug Administration (FDA). Once the expiration date passes, retailers cannot legally dispense lenses. A valid, unexpired prescription confirms that a licensed eye care professional has recently verified the lenses are safe for your eyes.
While federal law sets the minimum validity at one year, some states extend this to two years. A prescriber can shorten the expiration period to less than a year, but only if there is a specific, documented medical reason related to your ocular health. In the absence of a specific state law or medical complication, the standard expectation is that you will need a new exam for renewal every year.
What the Contact Lens Exam Evaluates
The annual contact lens exam is necessary because the health and shape of your eyes can subtly change over twelve months, affecting the fit and safety of the lenses you wear. The evaluation begins with an assessment of your corneal health using a slit lamp microscope, which allows the professional to view the front surface of the eye under high magnification. They inspect the cornea for signs of stress, such as staining, swelling, or new blood vessels (neovascularization), which indicates insufficient oxygen transmission.
A detailed check of the lens fit is performed while the lens is on your eye, assessing its movement, centration, and coverage. Proper fit is important because a lens that is too tight can restrict oxygen flow, while one that is too loose can cause irritation or poor vision. The professional also evaluates the quality and quantity of your tear film, as contact lenses can exacerbate existing dry eye.
This specialized assessment ensures the current lens material and wearing schedule are appropriate for your eye’s physiology and lifestyle. The eye’s curvature, diameter, and pupil size are measured to confirm the base curve and width of the lens are correct. Monitoring these factors prevents long-term damage and serious complications like microbial keratitis, an infection resulting from ill-fitting or poorly maintained lenses.
When Your Exam Frequency May Change
While the default schedule is annual, certain health conditions or lens types may require an evaluation sooner than twelve months. Patients who wear specialty lenses often require more frequent follow-up appointments because these complex lenses demand precise measurements and fittings. Examples of specialty lenses include:
- Scleral lenses
- Rigid gas permeable lenses
- Toric lenses for high astigmatism
- Multifocal designs
Patients with pre-existing ocular conditions like severe dry eye syndrome or systemic diseases like diabetes may be asked to come in more often. Diabetes can affect corneal sensitivity and healing, necessitating closer monitoring. If a patient has a history of poor hygiene leading to frequent eye infections, the doctor may recommend a six-month check-up to ensure compliance and prevent future issues.
Patients undergoing a trial period for a new lens type, material, or brand will have a mandatory follow-up appointment shortly after the initial fitting. If any discomfort, redness, or changes in vision occur, an immediate visit is required regardless of the prescription’s expiration date. The eye care professional’s medical judgment regarding your specific ocular health determines the final, personalized examination schedule.