Wearing contact lenses beyond their expiration date can introduce various risks to eye health. An expired contact lens is one used past the date indicated on its packaging by the manufacturer. Adhering to these dates is important for maintaining eye safety and the effectiveness of the lens.
Understanding Contact Lens Expiration
Contact lenses come with expiration dates primarily because the sterile packaging and the lens material itself can degrade over time. Lenses are sealed in blister packs with a sterile saline solution, which maintains their condition and prevents contamination. Over time, typically between one and four years from manufacturing, this seal can lose its integrity, even if not visibly broken, allowing air and bacteria to enter the package.
The saline solution within the package can also deteriorate, potentially becoming more acidic or alkaline, which can harm the lens material. While the plastic material of the lens does not technically “expire” like food, its physical properties, such as flexibility and oxygen permeability, can change.
Immediate Signs of Trouble
When a person wears expired contact lenses, immediate signs of trouble often manifest as discomfort and irritation. The eyes might feel scratchy or as if there is something foreign in them. Redness and dryness are common symptoms, as the degraded lens material can irritate the eye’s surface.
Blurred vision can also occur because expired lenses may lose their proper shape or accumulate deposits, affecting visual clarity. Burning or stinging sensations signal the lens is no longer compatible with the eye. These reactions serve as warning signs that the contact lenses should be removed.
Potential Eye Health Dangers
Wearing expired contact lenses significantly increases the risk of serious eye health complications. A primary concern is the increased likelihood of severe eye infections, such as bacterial keratitis, an inflammation of the cornea. The compromised sterility of the packaging allows bacteria, fungi, and even amoebae to contaminate the lens, which can then be transferred to the eye. These microorganisms can thrive on the lens surface, especially if the lens material has degraded or accumulated protein deposits.
Corneal ulcers, open sores on the cornea, can develop from these infections, causing pain and potentially leading to permanent vision damage. Expired lenses may also become less permeable to oxygen, depriving the cornea of the oxygen it needs to remain healthy. Oxygen deprivation can lead to corneal swelling, chronic redness, and new blood vessel growth into the cornea, potentially affecting vision. Irritation and infection from expired lenses can result in permanent vision impairment or even blindness.
Responding to Expired Lens Use
If someone realizes they have worn expired contact lenses or are experiencing symptoms, immediate action is important. First, remove the lenses from the eyes and discard them promptly. Avoid wearing any contact lenses until the eyes feel normal and comfortable again.
Even if symptoms appear mild, consult an eye care professional, such as an optometrist or ophthalmologist, to check for any underlying damage or infection. Always check the expiration date on the contact lens packaging before use and never extend the recommended wear schedule. Proper lens care and hygiene, including washing hands before handling lenses and using fresh, unexpired solution, reduce the risk of complications.