When standard contact lens solution is unavailable, temporary storage is required to prevent the lenses from drying out and minimize the introduction of harmful microorganisms. Proper lens care is directly linked to preserving eye health and preventing severe, vision-threatening infections. Storing contact lenses without the correct solution, even briefly, compromises the lens material and introduces contamination risks that must be immediately addressed.
Why Contact Lens Solution is Critical
Commercial contact lens solutions are complex medical devices with three distinct functions. The first is to provide essential hydration, keeping the lens material soft and flexible so it retains its specific shape. Without this constant moisture, the delicate lens structure can quickly dry out, leading to warping or becoming brittle.
The second and most significant function is disinfection, where the solution kills bacteria, fungi, and protozoa that accumulate on the lens surface throughout the day. These disinfecting agents eliminate harmful pathogens, such as Pseudomonas aeruginosa, which can cause rapidly progressing corneal infections.
Finally, solutions maintain a balanced environment through buffering agents that control pH and osmolarity (salt concentration). This careful balance mimics the eye’s natural tear film, ensuring the lens does not swell or shrink. Using a liquid with incorrect osmolarity can cause the lens to change shape, leading to discomfort or an improper fit that can scratch the cornea when reinserted. Commercial solutions also contain surfactants to clean away daily deposits of proteins and lipids, maintaining lens clarity and optimal vision.
The Only Approved Emergency Substitute
In the rare event that contact lens solution is not accessible, the only acceptable liquid for temporary lens storage is a sterile, unpreserved saline solution. This product is formulated to match the natural salt concentration of tears, preventing the lens from swelling or shrinking. Sterile saline’s sole purpose is rehydration and rinsing, not cleaning or disinfection.
If sterile saline is unavailable, preservative-free artificial tears may also serve as a very short-term hydrating agent. Any storage using these substitutes must be for the shortest possible duration, ideally no more than a few hours, only to keep the lens from becoming dry and damaged. Neither sterile saline nor artificial tears possess the necessary antimicrobial agents to kill infection-causing organisms.
The lenses must be kept submerged in a clean, sterile container, not an improvised one. This emergency method is a compromise to save the lens from drying out, meaning the lens remains potentially contaminated. Immediately upon access to commercial solution, the lens must undergo a complete cleaning and disinfection cycle.
Alternatives to Avoid at All Costs
Under no circumstances should tap water be used for contact lens storage or rinsing. Tap water contains numerous microorganisms, most notably the free-living amoeba Acanthamoeba. If this organism contaminates a contact lens, it can lead to Acanthamoeba keratitis, a severe and painful corneal infection that can result in permanent vision loss.
The different osmolarity of tap water also poses a physical threat to the lens material. Because tap water lacks the necessary salt concentration, soft contact lenses absorb it and swell, causing them to change shape and fit incorrectly. This swelling can lead to microscopic abrasions on the cornea, creating entry points for bacteria like Pseudomonas commonly found in water sources.
Saliva is another dangerous substitute due to the high concentration of bacteria present in the mouth. Placing a contact lens in saliva is equivalent to storing it in a microbial culture, greatly increasing the risk of serious bacterial keratitis.
Distilled water, while lacking mineral deposits, is not sterile once the bottle is opened. As a hypotonic solution, it lacks the necessary salt content, causing the lens to absorb water and swell significantly. This swelling can cause the lens to stick to the cornea, leading to pain and potential epithelial damage upon removal.
Finally, attempting to create a homemade saline solution by mixing salt and water must be avoided. It is impossible to guarantee the sterility of the water or the container. The resulting solution is unlikely to have the precise pH and osmolarity required, making it an ineffective and high-risk alternative.
Immediate Steps After Emergency Storage
Following any period of emergency storage, the first step is to acquire a fresh, commercial contact lens solution. The lenses must then be subjected to a full cleaning and disinfection cycle immediately.
This involves manually rubbing the lenses with the fresh solution for the recommended time, typically about 20 seconds, to physically dislodge any residual debris or microorganisms. After the physical cleaning, the lenses must be placed in a clean case filled with fresh solution for the minimum disinfection period, often six to eight hours, as specified by the solution manufacturer. This soaking time is necessary to ensure the disinfecting agents have sufficient time to kill any pathogens introduced during the emergency storage. If the lenses were dried out, they should be soaked for a minimum of 24 hours to ensure full rehydration.
Before reinserting the lenses, they must be carefully inspected for any visible signs of damage, warping, or tearing. If the lens shows any physical damage or feels uncomfortable upon insertion, it should be discarded immediately. Any symptoms of eye irritation, such as redness, pain, blurred vision, or light sensitivity, require the lens to be removed and immediate consultation with an eye care professional.