Contact lens wearers often run out of solution unexpectedly, leading to the temptation of using household liquids as a temporary substitute. Contact lens solution is a complex product designed to perform four functions: cleaning, rinsing, disinfecting, and hydrating the lenses. Using inappropriate substitutes can introduce bacteria or damage the lens material, potentially leading to serious eye infections or permanent vision damage. Proper solutions contain ingredients like surfactants and antimicrobial agents, formulated to maintain a sterile, balanced environment that protects both the lens and the delicate surface of the eye.
Why You Must Avoid Tap Water and Other Household Liquids
Using tap water, distilled water, or any non-sterile liquid for contact lens storage or rinsing poses a significant risk to eye health. Tap water is not sterile and contains microscopic organisms, including the amoeba Acanthamoeba. Exposure to this organism can lead to Acanthamoeba keratitis, a rare, painful, and sight-threatening infection of the cornea that is difficult to treat.
Beyond the threat of infection, non-saline liquids like water can damage soft contact lenses and the eye itself. Soft lenses require a saline environment matching natural tears to maintain their shape and water content. When lenses absorb non-saline water, they swell rapidly (osmotic shock), altering the lens fit. This tightening can create microscopic abrasions on the cornea, allowing microorganisms to enter and cause infection.
Using human saliva is also dangerous, as it is teeming with microorganisms that are harmless to the mouth but highly infectious to the eye. Introducing a contact lens to saliva is essentially placing it in a non-sterile, bacteria-rich environment that can transfer pathogens like Pseudomonas aeruginosa directly to the cornea. Homemade solutions, such as saltwater or boiled water, are also unsafe because it is nearly impossible to ensure they are sterile or have the correct salt concentration, which increases the risk of contamination and eye irritation.
Emergency Options for Temporary Contact Storage
If proper solution is unavailable, the safest immediate option for temporary storage and rinsing is sterile saline solution, available in pharmacies. Sterile saline is a simple, pH-balanced salt-and-water mixture that is safe for the eye, keeping the lens hydrated and maintaining its shape. It is important to understand that saline solution is only a rinsing agent and temporary storage medium; it contains no cleaning or disinfecting agents.
The lenses must be thoroughly cleaned and disinfected with a proper multi-purpose or hydrogen peroxide solution for the full recommended soaking time before they are worn again. If lenses are stored in sterile saline for an extended period, they will remain hydrated but will not be disinfected, leaving a layer of bacteria and debris on the lens surface. Preservative-free rewetting or lubricating eye drops, designed for use with contacts, can provide short-term hydration if the lens feels dry, but they are not suitable for overnight storage and offer no cleaning or disinfection.
When to Prioritize Eye Safety Over Saving Your Lenses
When no safe, sterile options are readily available, stop wearing the lenses immediately. The lenses should be removed and placed in a clean, dry contact lens case, or discarded entirely. Soft contact lenses must remain hydrated, and allowing them to dry out will likely ruin them, but this is a small loss compared to the risk of a serious eye infection.
The most prudent choice is to switch to wearing glasses until proper contact lens solution can be purchased. If the lenses were exposed to any unsafe liquid, such as tap water or saliva, they must be discarded immediately to prevent the transfer of dangerous microorganisms to the eye. If the eye feels irritated, red, or painful after removing the lens, or if there is any doubt about the safety of the liquid used, an eye care professional should be contacted right away.