Soft contact lenses require constant hydration to maintain their shape and flexibility. Running out of contact lens solution presents an immediate problem, and the impulse to quickly rehydrate a drying lens is understandable. However, substituting the proper cleaning and storage solution with common household liquids introduces serious risks to eye health. Only commercially manufactured contact lens solution is designed to clean, disinfect, and store lenses safely. If a proper solution is unavailable, prioritize eye health by following temporary rehydration measures, followed by thorough disinfection or disposal.
Why Dry Lenses Pose a Major Risk
A contact lens that has dried out becomes brittle and warped, significantly increasing the risk of physical damage to the eye. When a dry or partially dry lens is placed on the delicate corneal surface, it can cause microscopic breaks or a painful corneal abrasion. These tiny openings in the cornea act as entry points, making the eye highly susceptible to infection from microorganisms.
The lack of proper solution also compromises the necessary disinfection step, allowing bacteria, fungi, and parasites to proliferate on the lens surface. This contamination can lead to microbial keratitis, a severe and potentially sight-threatening eye infection. Ignoring disinfection, even after rehydration, escalates the danger of transferring these pathogens directly onto the cornea.
Dangerous Substitutes That Must Be Avoided
Tap Water
When faced with a dry lens and no solution, many people consider using tap water, but this is extremely dangerous. Tap water is not sterile and often contains microorganisms, including the hardy parasite Acanthamoeba, which can cause a rare but devastating eye infection known as Acanthamoeba keratitis. Soft contact lenses are designed for a saline environment; soaking them in hypotonic tap water causes the lens material to absorb water and swell. This swelling changes the lens fit, which can lead to microscopic trauma on the cornea and allow pathogens to enter.
Saliva
Using saliva to moisten or store a contact lens is highly ill-advised. The human mouth is densely populated with bacteria that are harmless in the digestive system but can cause severe infection if introduced to the eye. Placing a lens in saliva is essentially placing it in a bacterial culture, creating a high-risk environment for ocular infection.
Homemade Solutions
Homemade saline solutions, often involving salt mixed with boiled water, fail to provide a safe alternative for lens storage. While boiling water sterilizes it initially, the solution lacks the precise balance of salts and buffers necessary to maintain the lens material. More importantly, homemade solutions contain no disinfecting agents required to kill bacteria and fungi. Bottled or distilled water is similarly unsafe; while it may lack tap water minerals, it still lacks the necessary sterility and disinfecting properties required for contact lens care.
Emergency Measures for Rehydration
Rehydrating a Stuck Lens
If a lens is stuck to the eye because it has dried out, avoid pulling it off immediately, which could damage the cornea. Apply a few drops of sterile, preservative-free artificial tears or lubricating drops approved for contact lens wear directly to the eye. These drops restore moisture, allowing the lens to move freely on the tear film. Once the lens moves easily, it can be gently removed with clean, dry hands.
Temporary Storage
For temporary storage of a removed lens, the safest non-solution option is sterile, single-use vials of preservative-free artificial tears. These drops are formulated to be safe for the eye and provide temporary hydration to prevent the lens from completely desiccating and warping. Ensure the tears are not designed to reduce redness, as those contain vasoconstrictors not meant for lens storage. This rehydration is a short-term fix to maintain lens shape and must be followed immediately by a full disinfection process.
Proper Disinfection and Lens Disposal
After any emergency rehydration, the lens must undergo a full and proper disinfection cycle before reinsertion. Place the lens in a clean case filled with fresh, genuine contact lens multipurpose solution or a hydrogen peroxide-based system. The lens must soak for the manufacturer’s recommended time, usually a minimum of six hours, to ensure any pathogens introduced during the emergency are neutralized. Saline solution or rewetting drops alone will not disinfect the lens and should not be used for storage.
If a lens has completely dried out and has become brittle or shrunken, it is highly likely to be permanently damaged. Even after rehydration in solution, a warped or damaged lens can cause discomfort and corneal irritation. The lens should be carefully inspected for any cracks, cloudiness, or discoloration; if any damage is visible, the lens must be discarded immediately. If the lens feels uncomfortable or causes any eye irritation, redness, or blurry vision upon reinsertion, it should be removed and thrown away to prevent a serious infection.