Contact Lens Care Systems and Infection Control

Contact Lens Care Systems: Why the Right System Matters

A contact lens that is not properly cleaned, disinfected, and stored is a vehicle for microorganisms to reach the cornea. Microbial keratitis—infection of the cornea—is the most serious complication associated with contact lens wear, and most cases are linked to preventable behaviors: sleeping in lenses, topping off solution, using tap water, and using the wrong care system for the lens type. As an optician, you will be the last trained professional many patients see before they leave with their lenses. Your instruction can prevent vision-threatening infections.

Categories of Care Systems

Multipurpose Solutions (MPS)

Multipurpose solutions combine cleaning, rinsing, disinfecting, and storage in a single bottle. They contain a preserved disinfecting agent—commonly a biguanide such as polyaminopropyl biguanide (PAPB) or polyhexamethylene biguanide (PHMB), or a stabilized oxychloro complex—along with surfactants for cleaning and buffering agents for comfort.

How to use: Rub the lens with a few drops of solution for the time stated in the package insert (the "rub and rinse" step), then place the lens in a clean case filled with fresh solution for the minimum disinfection time specified. Most MPS products require several hours; overnight soaking is common and convenient.

Key points:

• "No-rub" labeling does not eliminate the mechanical rub step for safety—rubbing physically removes deposits and pathogens. Many practitioners and guidelines recommend always rubbing, regardless of label claims.
• Never top off solution in the case. Discard used solution, rinse the empty case with fresh solution, and allow it to air-dry face-down.
• Some patients are sensitive to preservatives in MPS, reporting stinging or chronic redness. This is a contra-indication to continued use of that product.

Hydrogen Peroxide Systems

Hydrogen peroxide systems use 3% hydrogen peroxide as the active disinfecting agent. Peroxide is highly effective against bacteria, fungi, Acanthamoeba cysts, and viruses. Because peroxide itself is toxic to the eye, every hydrogen peroxide system includes a neutralization step that converts the peroxide to water and oxygen before the lens contacts the eye.

Neutralization is accomplished either by a catalytic disk built into a specialized lens case or by a neutralizing tablet, depending on the product. The case or tablet must be used exactly as directed, and the minimum neutralization time stated on the package insert must be completed in full—this is typically around six hours for most products, but students must always verify the specific time on the insert for the product in use.

Critical safety warning: Placing a lens in the eye before neutralization is complete causes immediate, severe pain, corneal damage, and a chemical burn. This risk must be emphasized every time you instruct a patient on a hydrogen peroxide system. The specialized red-colored cases used by many peroxide products are a visual cue, but patients must understand why they cannot rush the process.

Key points:

• Preservative-free by the time neutralization is complete—ideal for patients with preservative sensitivity.
• Never pour hydrogen peroxide solution directly into the eye or a standard contact lens case.
• Do not use a neutralizing case past its replacement date; a worn-out catalytic disk will not neutralize fully.
• Hydrogen peroxide systems generally require additional daily cleaner or enzymatic tablets for heavy deposit wearers, depending on the product line.

Preservative-Free Care Systems

Preservative-free systems—including preservative-free saline and certain unit-dose rewetting drops—contain no antimicrobial preservative. They are used for patients with documented preservative intolerance and for rinsing rigid gas-permeable (RGP) lenses after enzyme cleaning.

Because preservative-free saline has no disinfecting capacity on its own, it must always be used as part of a complete care regimen that includes a separate disinfecting step. It is never a standalone care system for soft lenses.

Infection Control Principles in Lens Handling

Every contact lens interaction with a patient must reinforce the following core practices:

1. Hand hygiene first. Wash hands with soap and water and dry thoroughly with a lint-free towel before touching lenses.

2. Replace cases regularly. Cases are a major reservoir for biofilm. Replace the case at least as often as the solution bottle, or monthly.

3. Never use tap water. Tap water—including distilled water—can harbor Acanthamoeba, the organism responsible for Acanthamoeba keratitis, a rare but potentially blinding infection.

4. Never sleep in daily-wear lenses. Extended wear dramatically increases infection risk. Only lenses specifically approved for overnight wear may be worn that way, and only as directed by the prescribing practitioner.

5. Discard lenses on schedule. Using lenses beyond their replacement schedule allows protein and lipid deposits to build up, reducing oxygen transmission and harboring organisms.

6. Report symptoms immediately. Redness, pain, photophobia, or decreased vision in a lens wearer are red flags requiring prompt referral to the prescribing eye care practitioner—not self-treatment.

Matching the System to the Patient

Not every care system is appropriate for every patient or lens type. Hydrogen peroxide systems are often preferred for silicone hydrogel wearers with heavy deposits and for patients with MPS sensitivity. Preservative-free saline may be necessary for patients with severe chemical sensitivity. RGP lens wearers use different cleaners and conditioning solutions formulated for rigid lenses. Always follow the lens manufacturer's compatibility guidance and the prescribing practitioner's instructions.

Your Role in Patient Safety

As an optician, you are responsible for clear, complete patient education. Confirm patient understanding using teach-back: ask the patient to explain the steps back to you rather than simply asking, "Do you understand?" Document the care system dispensed and the instructions given. If a patient expresses confusion about the neutralization requirement of a peroxide system, slow down, repeat the explanation, and consider whether a different system might be safer for that individual.