Contact lens solution is a specially formulated product designed to clean, disinfect, and hydrate lenses, making it a medical necessity. Running out can cause panic, but using an improper substitute poses a serious threat of infection, irritation, or permanent eye damage. The immediate safety measure is to remove the lenses and switch to glasses. Attempting an unsafe substitution risks exposing your eyes to pathogens that the lens material can trap against the sensitive corneal tissue.
Immediate and Temporary Measures
If you find yourself in a situation where you must keep lenses hydrated for a short period (a few hours, not overnight storage), options are extremely limited. Sterile saline solution is the only safe liquid for rinsing or short-term hydration. Saline is a simple, pH-balanced saltwater rinse that contains no disinfecting or cleaning agents, unlike multipurpose contact solution.
Saline prevents the lens from drying out and warping, but it will not kill bacteria or remove protein deposits. Lenses stored in saline must be thoroughly cleaned and disinfected with a proper multipurpose solution before being worn again. Another temporary option is sterile preservative-free eye drops, often called artificial tears, which are safe for rewetting lenses while they are in your eye. These drops are formulated to be biocompatible with the eye’s natural environment but should never be used for cleaning or extended storage.
Liquids You Must Never Use
The temptation to use household liquids must be resisted, as many common substances carry severe risks of infection or physical damage to the eye.
Tap Water
The most dangerous substitute is tap water, which is not sterile and is a common source of the microscopic organism Acanthamoeba. If this amoeba gets trapped between the lens and the cornea, it can cause Acanthamoeba keratitis, a devastating eye infection that can lead to severe pain and permanent vision loss.
Tap water also contains minerals, such as calcium and magnesium, which rapidly bind to soft contact lenses. This mineral buildup irritates the eye and affects the clarity and fit of the lens. Additionally, the osmolarity (salt balance) of tap water differs from contact solution, which can cause soft lenses to swell or change shape, damaging the lens structure.
Saliva and Homemade Solutions
Another liquid to avoid is saliva, which contains a high concentration of bacteria from the mouth’s microbiome. Introducing these organisms directly to the eye dramatically increases the risk of a serious bacterial infection. Saliva lacks the disinfecting properties and pH balance required for safe contact lens care.
Similarly, attempting to create a homemade salt or saline solution is highly dangerous. It is impossible to achieve a truly sterile environment or a precise 0.9% sodium chloride concentration outside of a laboratory. Contamination is virtually guaranteed, and the resulting mixture will not disinfect the lenses. Even bottled or distilled water is unacceptable, as it is not guaranteed to be sterile and lacks the necessary disinfecting agents and chemical balance for lens care.
Safe Handling When Solution is Unavailable
Once the lenses have been removed, the focus shifts to minimizing harm until proper solution can be obtained. For daily disposable lens wearers, the safest action is to discard the lenses and use backup glasses. Attempting to save a daily lens without proper disinfection is not worth the risk of infection.
For reusable lenses, the immediate priority is to purchase multipurpose solution as quickly as possible. If you must wait, the last-resort option is to place the lenses in a clean, dry contact lens case. Lenses stored dry will desiccate and likely warp, but this is less risky than storing them in a non-sterile liquid.
When the new solution is acquired, the dry lenses should be soaked for the full recommended disinfection time (typically four to six hours) to allow for rehydration and cleaning. If the lens is visibly damaged, feels uncomfortable, or does not return to its original shape after soaking, it should be discarded immediately. Always use new solution to clean the lens case itself before placing lenses inside.