What Is Contact Lens Solution?

Contact lens solution is a care product used to clean, rinse, disinfect or store lenses, depending on their type. Solutions do not all have the same purpose: saline does not disinfect lenses, while multipurpose and hydrogen peroxide systems must be used according to their own instructions. Choose a product based on the lens type and the eye doctor’s advice.

Proper lens care can help reduce the risk of infection; however, no solution completely makes lens use risk-free. It is also important to manage the suitability of the product, as well as the handling of the lens case and usage duration correctly.

The primary function of the lens solution is to remove biological deposits that accumulate on the contact lens surface throughout the day. These deposits consist of proteins, lipids, calcium, and mucus found in the tear film, which accumulate over time to form a layer of buildup on the lens surface. This buildup reduces the lens’s oxygen permeability, leading to a decrease in vision quality and potentially creating conditions for complications such as neovascularization due to corneal hypoxia. The surface-active agents within the solution effectively remove these deposits through mechanical cleaning, thereby maintaining the lens’s optical performance.

Multi-purpose solutions or hydrogen peroxide systems suitable for disinfection, when used according to the product instructions, help reduce microorganisms. Saline and daily cleansers alone do not provide disinfection. The effectiveness and usage steps of products are not the same; no maintenance system completely eliminates the risk of infection. Some products also contain components that support lens moisture balance and ease of use.

Wash and dry your hands before touching contact lenses. When using a multipurpose solution, rub and rinse the lenses as instructed and place them in fresh solution each time. Check the product label for the required soaking time; there is no single duration that applies to all products. Do not mix solutions.

Discard old solution from the lens case. Clean and dry the case according to the care system’s instructions, and replace it regularly. Never top up old solution with new solution. Use hydrogen peroxide products only with their own neutralising case. Do not put lenses in before the time stated on the label has elapsed. Never put peroxide directly into the eye or use it to rinse lenses immediately before insertion.

Storing contact lenses outside of their solution is a practice that is not medically recommended, and carries significant risks of serious infection. When a solution is not available in an emergency, solutions that are often considered are tap water, bottled water, or saline, but none of these are suitable for the safe storage of contact lenses. Tap water, for example, can contain various microorganisms, including *Acanthamoeba*, which can adhere to the contact lens surface and cause *Acanthamoeba keratitis*, a corneal infection that is extremely difficult to treat and can result in vision loss. Bottled water and distilled water also carry similar risks.

If the appropriate solution is unavailable, wear glasses instead of contact lenses. Daily disposable lenses must be discarded after removal. Do not use water, saliva or homemade liquids for reusable lenses. Do not assume that a lens stored incorrectly or allowed to dry becomes safe simply by rewetting it; follow the manufacturer’s and eye doctor’s advice.

The expiration date of lens solutions indicates the point at which the disinfecting and protective agents within the product maintain their effectiveness at a safe level. After this date, the antimicrobial components in the solution begin to degrade, and its disinfecting capacity decreases gradually. Lenses cleaned with a solution that does not provide sufficient disinfection may harbor pathogens such as bacteria, fungi, and parasites, potentially leading to serious eye infections, including keratitis. Furthermore, the pH balance and osmolality of the solution can change over time; this change can negatively affect the lens material, causing deformation, dry eye, and cornea irritation.

The expiration date of the bottle must be checked separately from the usage period after opening. The period for which the product can be used after opening varies depending on the product; the period indicated on the label should be followed. The bottle tip should not come into contact with any surface, and products that have expired, are potentially contaminated, or have exceeded their usage period should not be used.

The primary criterion in lens solution selection is the compatibility of the solution with the type of contact lens being used. Soft hydrogel lenses, silicone hydrogel lenses, and rigid gas permeable (RGP) lenses have different material properties, and each material type exhibits different responses to various solution formulations. For example, certain preservatives can absorb onto the surface of silicone hydrogel lenses, leading to eye irritation. Therefore, it is important to stick to the solution type recommended by your lens manufacturer or eye care professional. If you wish to change your solution, it is essential to consult with your eye care physician or optometrist to prevent any potential incompatibility reactions.