Contact lens prescriptions expire for the same reasons that medical prescriptions expire. Any time you are using a medical product, you should follow up with your doctor at least once per year to identify possible complications. The FDA considers contact lenses medical devices. In 2004, a law was passed that set the expiration date of contact lens prescriptions at one year, or the minimum required by state law.

Just because your eyes and vision seem perfect, that may not actually be the case.

Remember that a contact lens is a foreign body placed into your eye. It lies on top of the cornea — the clear, dome-like structure on the front part of your eye. Contact lenses interact with the inner tissue lining of the eye, called the conjuctiva, underneath your eyelids. They also interact with your tears.

While the cornea provides most of the refractive power of the eye, it is made of living, breathing cells. Metabolic processes occur every day in the cornea, just as in the rest of your body. Debris and waste material from the cells in the cornea are excreted. This material can sometimes build up unnecessarily underneath a tight-fitting contact lens, creating a toxic environment for your cornea.

Overwearing contact lenses can lead to lactic acid build-up within the cornea, resulting in swelling. When swelling occurs, the cells in the cornea may spread apart. Bacteria and viruses can more easily enter these potential spaces in the cornea, possibly creating infection and scarring. Overwearing contact lenses can also lead to oxygen deprivation; new blood vessels will begin to grow into the cornea to try to feed it the oxygen it needs.

It’s important that you are checked out to make sure that your lenses are not causing problems, and that your prescription is accurate for your current needs. The next time you reluctantly schedule a contact lens check, remind yourself that you are protecting your vision by maintaining the health of your eyes.

_Source: 

American Optometric Association. What You Need to Know About Contact Lens Hygiene & Compliance. AOA.com, 2006-09.

Contact Lens Frequently Asked Questions

Putting contact lenses on: step by step.

STEP 1: Thoroughly wash and dry your hands with soap and a clean towel.

STEP 2: Rinse your lens with solution to remove any trace of debris. (If you’re using a new lens, or 1-DAY  Brand Contact Lenses, simply take them out of the package, no solution is needed) Tip: To avoid mixing up your contact lenses, always apply and remove the lens for your RIGHT eye first.

STEP 3: Place the lens on the tip of your index finger. Be sure the lens is correctly oriented by checking the inside–out marker.

STEP 4: Use your other hand to hold your upper eyelid so you won’t blink.

STEP 5: Pull down your lower eyelid with the other fingers of your applying hand.

STEP 6: Look up at the ceiling and gently place the lens on the lower part of your eye.

STEP 7: Slowly release your eyelid and close your eye for a moment.

STEP 8: Blink several times to center the lens. You’re all set.

STEP 9: If your lens feels uncomfortable, remove it and inspect for damage or debris. If it’s damaged, discard it. Otherwise, rinse with more solution and reapply.

Taking contact lenses off: step by step.

STEP 1: Thoroughly wash and dry your hands with soap and a clean towel.

STEP 2: Look up at the ceiling and pull down your lower eye lid. Tip: To avoid mixing up your contact lenses, always apply (and remove) them in the same order.

STEP 3: Bring your index finger close to your eye until you touch the lower edge of the lens.

STEP 4: Slide the lens down to the lower white part of your eye.

STEP 5: Gently squeeze the lens between your thumb and index finger and remove it.

STEP 6: Remove the other lens following the same procedure.