What are the effects of wearing expired contact lenses?
With everything we know about how synthetic materials will last forever in landfills, it's surprising to learn that contact lenses have expiration dates. What's up with that? Well, it's not actually the lenses themselves that expire, but the solution they come packed in.
What are the effects of wearing expired contact lenses?
Wearing expired contact lenses isn't good (like, that's what this whole article is about). But what are the effects of wearing expired lenses? What happens if you wear expired contacts, and why does it happen?
Quick intro to contact lens expiration dates (and why it matters)
Most of the lenses you get have an expiration date on them. For most lenses, this is not the fault of the lenses themselves, which are mostly made from polymer or silicone hydrogel, but the packaging and solution.
Contacts come sealed in airtight packets that you have to peel open. Beyond a certain (or rather, uncertain) point, the contact lens manufacturer anticipates that the pack seals may fail or allow outside air into the contact storage area. When that happens, several issues can make your lenses unfit for use.
Loss of solution
When seals fail, the packs are no longer airtight and can dry out, which has the potential to damage the lenses. The broken seal can also let in bacteria, which is bad to have in your eye.
Changes in lens material and structure
Apart from contamination, dryness is bad for the lenses themselves. You may not know this, but your eyes have tears in them. Contacts are designed to basically always be moist, and when they dry out, they tend to warp and split.
Because lenses work by bending light through a very specific shape, any changes to that shape can cause blurry vision and reduce their effectiveness. Dry lenses are also a drag by themselves, but wearers already know this.
Risks to eye health from expired lenses
All these issues cause some hard-to-ignore health issues you'd probably rather avoid.
Risk of infections
Contact solution is sterile, and it helps kill off bacteria that get into it. When an expired pack leaks out all its solution, those bacteria aren't being killed anymore. Bacteria in the eye can lead to infections and other negative outcomes.
Corneal abrasions and causes of irritation
Dry contacts can also feel bad, and that's a problem. They also cause abrasions (that's scratches ... in your eye). Over the short term, this is irritating, but in the long term, it can cause swelling of the cornea and significant pain or vision impairment.
Reduced oxygen permeability
Corneas can also swell up if they're deprived of oxygen, which sometimes happens with extended contact lens use. Believe it or not, your eyes breathe, and dry, worn-out lenses block the air that they need.
This swelling feels bad, can alter your vision, and can develop into a real problem over time. In extreme cases, your vision can get noticeably worse and may become seriously impaired if nothing is done to stop it.
Visual disturbances and ongoing discomfort
Beyond the physical risk of wearing expired contacts, there's a functional issue. As in, your lenses just may not work right when they've expired.
Blurred vision
Dry lenses have different geometry from unexpired, properly moist contacts. Even if you try rehydrating expired lenses, they may never get back to where they should be and should be discarded. If you're wearing contact lenses for vision correction, this is obviously counterproductive.
Dryness and discomfort
Even if they're still the right shape, "dry contact lenses" is one of the least fun phrases you can hear. Dry contacts feel bad, often fail to work properly, and need to be replaced as soon as possible.
Expired lenses are just bad news all around
So, what are the effects of wearing expired contact lenses? Basically, nothing good. Instead of taking the risk of wearing old and potentially dangerous lenses, schedule an appointment with your eye care professional and keep a regular supply of fresh, unexpired contact lenses.
FAQs
Can wearing expired contacts cause permanent eye damage?
Over time, the irritation and risk of infection that comes with expired contact lenses can lead to damage from abrasions and infection, which may be permanent.
How can I tell if my contact lenses are expired?
Contact lenses have expiration dates printed on their packets. Check this before you start using a new set of lenses.
What should I do if I accidentally wear expired contacts?
Don't panic. Everything should be okay if you've just made a one-off mistake. Remove the lenses, put in a fresh pair, and use drops for irritation.