Contact lens solution is a complex, carefully balanced formula engineered for three specific purposes: disinfection, hydration, and maintaining the lens’s physical integrity. It contains biocides to kill microbes, surfactants to clean debris, and buffering agents to ensure the correct pH and osmolarity. Any alternative liquid used represents a temporary, non-sterile compromise that lacks these protective qualities.
Short-Term Storage Options
In an emergency, the safest temporary liquid is a sterile, non-medicated saline solution, sometimes found in first-aid kits or used for wound rinsing. This solution is isotonic, meaning its salt concentration is similar to natural tears. This prevents the lens material from swelling or shrinking, keeping the lenses hydrated and preventing damage.
Sterile saline only serves as a hydrating rinse and storage medium; it contains no disinfecting agents. The lenses are not cleaned while stored in this liquid. This option should only be used to keep the lenses wet for a few hours until a proper multipurpose or hydrogen peroxide solution can be purchased. If sterile saline is unavailable, a last resort is to store the lenses completely dry in a clean case. This prevents microbial growth but requires an extended rehydration and disinfection period later.
Severe Risks of Improper Storage
Using common household liquids like tap water, bottled water, or saliva poses severe risks to ocular health and must be avoided. Tap water, even if potable, is not sterile and is a common reservoir for microorganisms that cause serious infections. It contains various bacteria, fungi, and, most notably, the parasite Acanthamoeba.
Exposure to water can lead to Acanthamoeba keratitis, a sight-threatening corneal infection that is difficult to treat. This risk exists because tap water has low osmolarity compared to natural tears, causing the contact lens material to absorb water and swell. The swollen lens changes its fit on the eye and can create microscopic abrasions on the cornea. This allows microorganisms to penetrate the protective surface and cause infection.
Using saliva to moisten or store lenses is dangerous because the human mouth is teeming with bacteria specific to the oral cavity. Transferring this high concentration of oral bacteria directly to the lens and then to the eye increases the risk of severe bacterial keratitis. Even distilled or bottled water is not sterile and still presents a contamination risk and the damaging osmotic effect on the lens material.
Protocol After Using a Substitute
If lenses were stored in an unapproved substitute like sterile saline or water, an immediate and thorough decontamination protocol is mandatory before reinserting them. The first step is to acquire a fresh bottle of multipurpose or hydrogen peroxide disinfecting solution. Do not use the lenses again until they have completed a full disinfection cycle in the proper solution.
Manually rub and rinse the lenses according to the manufacturer’s instructions. Then, soak them in the fresh solution for the maximum recommended disinfection time, which is often between six and eight hours. This extended soaking period helps neutralize residual contaminants. If the lenses were stored in water or saliva for more than a few hours, discard them immediately to eliminate infection risk. Monitor your eyes closely for symptoms such as redness, pain, blurred vision, or light sensitivity, and consult an eye care professional if any of these signs appear.