Wearing contact lenses is a common and safe way to correct vision, but they are classified as medical devices, meaning their use is strictly regulated, especially concerning their expiration date. The short answer is no, it is not safe to use expired contact lenses. The expiration date printed on the packaging is a guarantee of sterility and product integrity. Once this date passes, serious risks to eye health are introduced. This article explains what that date signifies, the health consequences of ignoring it, and what steps to take if you have used an expired pair.
Understanding the Expiration Date
The expiration date (often marked “EXP”) signifies the end of the manufacturer’s guarantee that the product remains safe and effective. This date is determined by rigorous testing required by regulatory bodies like the U.S. Food and Drug Administration (FDA). It represents the tested shelf-life of the entire sealed environment, including the lens, the buffered saline solution, and the packaging seal integrity.
The primary concern is that the sterile environment becomes compromised over time. The foil and plastic blister pack, though airtight, can degrade microscopically over years, creating tiny, invisible breaches. These gaps allow contaminants like bacteria, fungi, or amoebas to enter the saline solution. This turns the sterile package into a hazardous environment.
The saline solution itself also has a limited shelf life. Over time, stabilizing agents can lose effectiveness, or the delicate pH balance can shift, becoming more acidic or alkaline. This chemical change means the lens is no longer guaranteed to be stored in an inert, non-irritating medium. Once the expiration date passes, the manufacturer cannot ensure the sterility and chemical stability required for safe use.
Health Consequences of Using Expired Lenses
The most severe risk associated with using expired contact lenses is introducing infectious agents to the eye. Compromised packaging allows microorganisms to contaminate the lens and solution, which transfers directly to the cornea upon insertion. This contamination significantly elevates the risk of sight-threatening conditions such as microbial keratitis, an infection of the cornea.
Microbial keratitis can be caused by bacteria, fungi, or Acanthamoeba, a type of amoeba. It is a medical emergency that can lead to corneal ulcers and permanent vision loss if not treated immediately. The contaminated lens acts as a vector, trapping pathogens directly against the eye’s surface. Even without a severe infection, the chemically altered or contaminated solution can cause immediate irritation, burning, and redness upon insertion.
The lens material itself may also degrade or change properties past the expiration date. Contact lenses are engineered for specific oxygen permeability to the cornea. Over time, the material can lose its physical characteristics, reducing oxygen transmission and leading to corneal hypoxia (oxygen deprivation). Hypoxia causes the cornea to swell, leading to blurred vision and complications like corneal neovascularization, where new blood vessels grow into the clear cornea.
Material breakdown also affects the lens’s surface smoothness and flexibility. A brittle or warped lens can cause physical trauma, leading to microscopic abrasions or scratches on the corneal surface. These tiny breaks create an entry point for bacteria and increase the likelihood of developing a painful corneal ulcer.
What to Do If You Have Used Expired Lenses
If you realize you have worn an expired contact lens, the immediate action is to remove it and discard it, along with any other expired lenses you may own. Avoid putting any other lenses into the affected eye until you have assessed your symptoms. If your eyes feel normal, monitor them closely, but consult an eye care professional to report the incident.
You must seek immediate medical attention from an optometrist or ophthalmologist if you experience any symptoms of an eye infection. These warning signs include pain, persistent redness, blurred vision, excessive tearing, or an unusual sensitivity to light. These symptoms can indicate a serious issue like microbial keratitis, which requires prompt treatment to prevent permanent damage.
Even if symptoms are mild, such as slight irritation, discomfort, or a scratchy feeling, a consultation is recommended to have your eye examined. An eye doctor can check for subtle signs of corneal irritation, inflammation, or early-stage infection that may not be obvious to you. Never try to treat a potential infection at home, as using expired contact lenses is an unnecessary gamble with your vision that should always be followed up with professional guidance.