Contact lenses are medical devices that require careful maintenance for clear vision and eye health. The proper use of contact lens solution is the primary factor in this routine. This specialized liquid cleans, disinfects, and rewet the lens surface, removing accumulated debris and microorganisms. Following the specific guidelines for solution usage is necessary to protect eyes from infection and irritation.
The Daily Replacement Rule for Lens Cases
The most direct answer to how often you should change your contact solution is every single time you remove your lenses for storage. This daily replacement rule applies whether lenses are stored for an hour or overnight. The act of removing the lenses and placing them in the case immediately introduces eye proteins, lipids, and other tear film debris into the liquid.
The solution’s disinfecting agents are designed to neutralize these contaminants and kill microorganisms, but this process quickly depletes the chemical’s efficacy. Reusing old solution, often called “topping off,” means placing lenses into a contaminated, partially neutralized liquid that is no longer capable of full disinfection. This practice promotes the formation of a biofilm on the case and lens surface.
Using a fresh dose ensures the active disinfecting ingredients are at full concentration for optimal lens hygiene. The consistent action required is simple: discard the old solution, rinse the case with fresh solution, and then refill it completely before placing the lenses inside. This step significantly reduces the risk of serious eye complications. If lenses are stored for an extended period, such as over a week, replace the multipurpose solution periodically according to the manufacturer’s instructions.
Why Solution Type Matters for Storage
Not all contact lens solutions are the same, and the type you use dictates the specifics of your storage procedure. The two primary categories are multipurpose solutions (MPS) and hydrogen peroxide (HP) systems. MPS are all-in-one liquids that clean, rinse, and disinfect, offering simplicity and convenience for daily storage.
HP systems use a potent 3% hydrogen peroxide solution for deep cleaning. This system requires a special case with a neutralizing disc or tablet to convert the peroxide into a gentle saline solution over at least six hours. Lenses must remain in the system for the entire neutralization cycle. Never rinse or store lenses in un-neutralized HP solution, as direct contact with the eye can cause severe chemical burns.
Once neutralization is complete, the lenses sit in sterile saline, and the solution’s disinfecting power is exhausted. If lenses are left in the case for long-term storage, they risk re-contamination and require a fresh cleaning cycle. MPS maintain their disinfecting properties longer, often allowing for safe storage for up to 30 days, provided the solution is changed weekly.
Solution Lifespan: Expiration and Bottle Hygiene
Beyond the daily change in the lens case, the lifespan of the solution in the bottle itself must be strictly managed to maintain sterility. Solution has an expiration date printed on the bottle. Using it past this date compromises the chemical stability of the disinfectants, causing the solution to lose its ability to effectively kill pathogens, even if the bottle remains unopened.
A frequent concern is the solution’s discard date after opening. Most manufacturers advise discarding the remaining solution within 90 days of breaking the seal. Once opened, the solution is exposed to air and potential contaminants, which can degrade the preservatives and reduce sterility.
Proper bottle hygiene is necessary to prevent contamination of the bulk solution. Never touch the tip of the solution bottle to any surface, including fingers, the lens case, or the counter. The cap must be tightly closed immediately after use, and the bottle should be stored in a cool, dry place away from moisture.
Health Risks of Reusing Contact Solution
Reusing or topping off contact lens solution poses a significant threat to eye health, directly increasing the risk of severe ocular infections. When the old solution’s efficacy is spent, bacteria, fungi, and protozoa multiply in the lens case and adhere to the lens surface, transferring these pathogens to the eye.
One concerning outcome is microbial keratitis, an infection of the cornea caused by various organisms, including Pseudomonas aeruginosa bacteria. A devastating infection linked to poor solution hygiene is Acanthamoeba keratitis (AK). This is a rare but sight-threatening infection caused by a microscopic amoeba often found in water. Inadequate disinfection allows it to thrive, leading to severe eye pain and potentially requiring a corneal transplant.
Studies show that a high percentage of AK cases are associated with avoidable risk factors, such as failing to use fresh solution daily. Consistently using fresh solution ensures disinfecting agents are always working, effectively reducing the bio-burden on the lens and the case.