Proper care for reusable contact lenses requires understanding the limits of the disinfecting solution. The duration lenses can safely remain submerged depends on the specific solution formulation and storage environment. Using a fresh, unexpired solution every time lenses are stored is fundamental for maintaining eye health and lens integrity. This ensures the lenses are clean and safe to wear when inserted.
Understanding Solution Effectiveness
The ability of contact lens solution to keep lenses disinfected decreases over time. Solutions contain specific preservative and disinfecting agents, such as polyquaternium-1 or polyaminopropyl biguanide, designed to neutralize microbes and maintain a sterile environment. These agents work most effectively during the initial soaking period, typically four to eight hours, to achieve primary disinfection.
Once in the case, the solution interacts with debris, proteins, and tear film components from the eye. These organic materials neutralize active ingredients, reducing the solution’s antimicrobial potency. Preservatives can also break down chemically if exposed to heat, light, or air, diminishing their ability to prevent microbial growth. This decay transitions the solution from an active disinfectant to a simple, non-sterile soaking medium.
Standard and Extended Storage Durations
Storage time limits depend on the intended duration of storage. For routine, short-term storage, such as overnight or between daily wears, lenses must remain in fresh solution for the manufacturer’s recommended disinfection time, typically six to eight hours. If lenses are worn daily or every few days, the solution must be replaced with a fresh fill each time the lenses are removed.
For extended storage, when lenses are not worn for a week or longer, the maximum safe duration varies by product. Most multipurpose solutions allow storage in a sealed case for up to 30 days before the solution must be replaced and the lenses re-disinfected. Hydrogen peroxide systems often have shorter maximum storage recommendations, sometimes as short as seven days. Always consult the specific solution packaging for the definitive maximum storage time.
Health Risks of Improper Storage
Exceeding the recommended storage time increases the risk of serious eye health complications. The primary danger is the proliferation of microorganisms, including bacteria and pathogens like Acanthamoeba, which can lead to severe infections such as microbial keratitis. When the solution’s disinfecting power wanes, the lens case becomes a breeding ground for these microbes, contaminating the lens.
Prolonged storage also risks the solution level dropping due to evaporation, especially if the case is not tightly sealed. If lenses are no longer fully submerged, they can dry out, warp, or become physically damaged. Inserting a dried or warped lens can result in corneal abrasions and eye discomfort.
Furthermore, accumulated protein and lipid deposits, which the weakened solution cannot clean, can trigger allergic reactions, irritation, or reduced visual clarity.
Post-Storage Care and Case Hygiene
Specific protocols must be followed to maintain safety, regardless of storage duration. If lenses have been stored for the maximum recommended time, they must be thoroughly cleaned, rinsed, and soaked in a fresh batch of solution for a complete disinfection cycle before wearing. If lenses remain in the same solution beyond the manufacturer’s maximum recommendation, it is safest to discard them entirely to avoid infection risk.
Avoid “topping off” old solution with new solution, as this dilutes the fresh concentration and reintroduces contaminants. The lens case requires daily cleaning by emptying the old solution, rinsing with fresh solution, and allowing it to air-dry face down on a clean tissue. The contact lens case should be replaced with a new one every one to three months to prevent the build-up of biofilm and bacteria.