You’ve seen expiration dates stamped on everything from the milk in your refrigerator to the batteries in your TV remote. You can get away with using many products for a few days – or even weeks or months – after the expiration date. Using other products past their expiration is asking for trouble.
If you wear contact lenses, you may notice that the packaging they come in is stamped with an expiration date, as well. You may have wondered if a contact lens’s expiration date is a hard-and-fast rule or if it’s one of those dates that’s more of a suggestion.
Do contact lenses expire? They absolutely do, and continuing to use them past their expiration can be a dangerous gamble with your eyesight. This month, we’ll examine different types of contact lenses, when and why they expire, and why you should pay close attention to your contacts’ expiration dates.
Do All Contact Lenses Expire?
Yes, all contact lenses have an expiration date, and that date is there for your protection. Nearly all contact lenses on the market today fall into one of three categories:
- Soft contact lenses are by far the most common, making up more than 90% of the contact lens market.
- Rigid gas permeable lenses are less common but provide some advantages over soft contact lenses for users who can get used to the harder, less comfortable lens.
- Hybrid contact lenses combine the two, with a rigid center surrounded by a ring of soft contact material.
All three of the above types of contacts are made from special plastic polymers that allow oxygen to pass through, allowing the eye to “breathe” and preventing the lenses from causing undue irritation.
Why Do Contact Lenses Expire?
There are a few reasons why contact lenses expire after a given period:
Saline Solution Expires
All contact lenses are manufactured in a sterile environment and then sealed into packaging along with a saline solution that keeps the lenses from drying out. Over time, that saline solution begins to degrade and may become either acidic or alkaline, both of which can damage the lenses themselves. The saline also loses its sterile qualities and can start to harbor dangerous pathogens.
Polymers Lose Permeability
The special polymers that allow oxygen to penetrate the contact lens and reach the surface of the eye degrade slowly over time. Past a contact lens’s expiration date, the lens may become dangerously impermeable, not allowing adequate oxygen to reach the eye.
Lens Prescriptions Expire
Your contacts actually have two expiration dates: one when the lenses themselves are no longer safe to use and one tied to your vision prescription. In Georgia, contact lens prescriptions are only valid for one year after they’re written. If you have contacts that were prescribed more than a year ago, then your prescription is out of date, and you should schedule an eye exam before you continue wearing your contacts.
What Can Happen if I Wear Expired Contact Lenses?
Three significant complications are likely to arise if you persist in wearing contact lenses after their expiration date.
Expired Contact Lens Threat #1: Dry Eyes
As mentioned above, contact lenses lose permeability over time. Once the permeability is too low to allow oxygen to reach your eyes, your eyes will slow down tear production and begin to dry out more readily.
Dry eyes are a pain in and of themselves—they itch, burn, and feel “gritty.” They cause significant discomfort that can make getting through the day challenging and can make things like reading and working at a computer nearly unbearable. But dry eyes can cause more than discomfort.
Tears are your eyes’ first line of defense against infections of various types, and individuals with dry eyes are far more susceptible to almost every kind of eye infection known.
Expired Contact Lens Threat #2: Eye Infections
Not only can expired lenses make eye infections more likely due to reduced tear production, but they can actually introduce dangerous pathogens directly to the surface of your eye. The same permeability that allows oxygen to pass through a contact lens means that the lens itself can trap things like bacteria and viruses. The longer you wear a particular set of lenses, the more germs it collects.
A common infection seen in patients who’ve used expired contact lenses is bacterial keratitis. Keratitis is an infection that causes inflammation of the cornea, and symptoms including:
- Redness
- Light sensitivity
- Pain
- Blurry vision
If left untreated, keratitis can become a dangerous infection that can lead to permanent vision damage or even vision loss.
Expired Contact Lens Threat #3: Eye Strain and Fatigue
Even if your contact lenses are fresh and have a manufacturer’s date that’s years away, if your lens prescription has expired, they can damage your eye.
Your eye changes constantly. After a year of wearing lenses with a given prescription, your vision will have changed from what it was the year before. If you don’t get an eye exam and an updated prescription, you could be wearing contacts that are under or over-correcting your vision. This corrective error can lead to blurry vision, eye strain and fatigue, and other secondary symptoms such as severe headaches and irritability.
Contact wearers should routinely get an eye exam each year to make sure that their lens prescription is up to date and that their lenses are doing their job.
Don’t Get Caught With Expired Contact Lenses. Call Eyesight Associates and Schedule an Exam Today!
Don’t wait until your lenses are out of date! With eight locations around the midstate and the Golden Isles, we’re always close at hand to help you maintain clear vision! Call 478-923-5872 to learn more or make an appointment.
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