Contact lenses are medical devices requiring strict adherence to care guidelines to prevent serious eye complications. Most contact lens-related eye infections and vision damage stem from improper handling and misuse, not the lenses themselves. These mistakes create a pathway for harmful microorganisms to reach the cornea, the transparent outer layer of the eye. Avoiding specific errors in hygiene, wear schedule, and lens maintenance is paramount for maintaining clear vision and long-term eye health.
Errors Related to Water and Moisture Exposure
Never allow tap water or any non-sterile water to contact your contact lenses or their case. Tap water contains microorganisms, including the parasite Acanthamoeba, which adheres to the lens surface. If this organism infects the cornea, it can cause Acanthamoeba keratitis, a condition characterized by severe pain that may result in permanent vision loss or blindness.
Avoid showering, swimming, or using a hot tub while wearing lenses, as this exposes them to waterborne pathogens. The lens material can absorb water, causing soft lenses to swell, warp their shape, and stick tightly to the eye, which can damage the corneal surface. Even distilled or bottled water is not safe for contact lens care, as it is not sterile for ophthalmic use.
Microbes from water sources can be trapped between the lens and the eye, multiplying rapidly. Always ensure your hands are thoroughly washed with soap and completely dried before touching your lenses, as water residue easily transfers pathogens.
Mismanagement of Wear Time and Sleep
Wearing lenses longer than the prescribed daily limit (overwearing) or sleeping in lenses not approved for extended wear significantly increases complication risks. The cornea receives oxygen primarily from the air, and a contact lens reduces this necessary oxygen flow. Wearing lenses too long results in corneal hypoxia, a state of oxygen deprivation.
When the cornea is starved of oxygen, it swells, which can impair vision. Chronically, the eye attempts to grow its own blood supply through corneal neovascularization. This pathological process involves new, fragile blood vessels invading the normally clear tissue to deliver oxygen. These new vessels compromise the cornea’s transparency, potentially leading to permanent vision degradation.
Lenses approved for extended wear allow greater oxygen permeability, but sleeping in any lens increases the risk of infection by six to eight times. This is because the closed eyelid further reduces oxygen access and prevents the natural flushing mechanism of tears. Replace daily, bi-weekly, or monthly lenses strictly according to the schedule to prevent deposit buildup and reduce hypoxia risk.
Mistakes in Cleaning Solutions and Storage
A dangerous error is “topping off” the solution in the lens case by adding fresh solution to the old, used liquid. The disinfecting chemicals in the old solution are neutralized and have lost efficacy. Adding new solution to this depleted mixture dilutes the fresh disinfectant, allowing microorganisms to thrive and contaminate the lenses.
Always discard the old solution completely and fill the case with fresh, manufacturer-recommended disinfecting solution every time lenses are stored. Never use unapproved liquids, such as plain saline solution, rewetting drops, or water, for cleaning or disinfecting. Saline is only for rinsing and lacks the necessary agents to kill harmful microbes, which is the function of a disinfecting solution.
The lens case is a significant source of contamination and must be maintained properly. Rinse the case with fresh solution after each use, wipe it dry with a clean tissue, and store it open and upside down to air dry. The case should be replaced entirely every one to three months, as biofilms can develop on the plastic surfaces even with proper cleaning, reducing storage safety.
Ignoring Symptoms and Proper Lens Fit
Any sign of eye discomfort or change in vision warrants immediate lens removal and professional consultation. Warning signs of a potential infection or corneal complication include persistent eye pain, unusual redness that does not subside, blurred vision, excessive tearing, increased light sensitivity, or the feeling that something is stuck in the eye.
Wearing lenses that are not properly fitted can cause corneal abrasions, which act as entry points for infection. Never share contact lenses, as this transfers bacteria and pathogens. Cosmetic or decorative lenses must be obtained with a valid prescription, as those purchased without professional oversight can be poorly fitted and cause serious injury.
Continuing to wear lenses with an outdated prescription is ill-advised, as eye health may have changed since the last examination. Safe use depends on following the precise instructions and parameters set by the prescribing eye care professional. Ignoring discomfort and attempting to “tough it out” can quickly turn a minor irritation into a serious, vision-threatening condition.