The majority of contact lens patients today are fit in silicone hydrogel lens materials.1 These lenses, first introduced in the late 1990s, allow for increased oxygen to reach the cornea. But, as we all know, advances in contact lens materials alone cannot forestall all contact lens-related complications.
Even with the introduction of newer materials and solutions, non-compliance is still a challenge that manufacturers and eye care providers face.2 Research has shown that 40% to 90% of contact lens wearers are non-compliant in at least one aspect of their wear.2 When you consider that patients cite comfort as the primary reason for discontinuing contact lens wear, it is even more important for practitioners to prescribe the right pairing of contact lens material and contact lens solution to reduce complications.3
This article will describe the three new silicone hydrogel-compatible multipurpose solutions available today.
The History of MPDS
Multipurpose disinfecting solutions have always tried to strike the appropriate balance between convenience and efficacy. Recognizing patient reluctance to use a two-step regimen, they allow patients to use a single product to rinse, disinfect and store their contact lenses. These solutions contain preservatives, buffering systems and disinfecting agents that decrease microbial activity while enhancing patient comfort.4
It is important for eye care practitioners to be aware of how different contact lens materials react to various solutions. This interaction can play a key role in the overall performance of the contact lens.5 Three of the most recently introduced multipurpose solutions on the market today—Biotrue (Bausch + Lomb), Opti-Free PureMoist (Alcon) and RevitaLens OcuTec (Abbott Medical Optics)—have been specifically approved by the FDA for use with silicone hydrogel contact lenses.6 When recommending solutions for our silicon hydrogel lens wearers, it is important to select a solution that has adequate disinfecting properties—which helps rid the surface of proteins and lipids, while not compromising surface wettability.
The International Organization for Standardization (ISO), charged with grouping contact lenses for testing purposes, categorized lenses into four groups based on water and ionic content of the lens material. The FDA approved these categories in 1994. However, with the subsequent introduction of silicone hydrogel lenses to the market, it became obvious that these unique materials need their own group designation.
The ISO created a fifth group in 2009 to encompass all silicone hydrogel lenses.5 Efforts are currently underway to further subdivide group 5 based on lens porous structure, water content, lipid affinity/hydrophobicity, ionic charges, surface treatments and preservatives/surfactants differences.
In 2010, the FDA made new labeling recommendations for healthier contact lens wear: The terminology, “no-rub,” was to be removed from solution product labels and the importance of rubbing for proper cleaning was to be enforced by the practitioner.7
New Market Additions
• Biotrue is Bausch + Lomb’s newest addition to the multipurpose contact lens solution market. Designed to mimic the biology of the eye itself, this solution contains a pH level equal to that of healthy tears, which the manufacturer says minimizes irritation upon contact lens insertion. Biotrue contains hyaluronan, a naturally occurring lubricant found in tears, which increases contact lens wettability. It also includes dual disinfectants—polyquaternium-1 and polyhexamethylene biguanide—to enhance the solution’s antimicrobial activity by keeping lysozyme and lactoferrin active.8
• Alcon’s Opti-Free PureMoist is one of the newer multipurpose solutions to enter the market. It has similar disinfecting properties, polyquaternium-1 (PQ-1) with myristamidopropyl dimethylamine (Aldox), to other Opti-Free brand solutions but was designed to decrease corneal staining and promote contact lens end-of-day comfort.1 Opti-Free PureMoist has a higher concentration of Aldox (0.0006%) compared to Alcon’s Opti-Free Replenish (0.0005%). With a Polyquad and Aldox dual action disinfecting system, combined with the proprietary HydraGlyde Moisture Matrix wetting system, the manufacturers report a decrease in corneal staining, which may reduce a patient’s risk of microbial infection and enhance patient comfort. The solution also contains EDTA, a chelating agent. Contact lenses can be stored safely in this solution for up to 30 days.3
• RevitaLens OcuTec multipurpose solution from Abbott Medical Optics is the third new introduction to the market and reports a similar disinfection kill rate as hydrogen peroxide-based systems. But unlike hydrogen peroxide systems, which lose their effectiveness once neutralized, RevitaLens maintains its disinfecting properties for up to 30 days. The solution contains dual acting disinfecting agents—PQ-1 and alexidine dihydrochloride—and is considered >99.9% effective against Acanthamoeba trophozoites and resistant cyst stage, as well as other microbial pathogens.9
Keep in mind that current ISO standards do not require Acanthamoeba testing for new multipurpose solutions entering the market, but the FDA has recommended that this criteria be added.6 Research has shown RevitaLens sustains antimicrobial ability in noncompliant patients who “top off” the solution in their contact lens cases.9
Each system offers unique features, and this product class is developing a body of scientific evidence that may guide product selection in the future.10,11 For now, patients wearing a SiHy lens would likely do better with any product in this category than with a single disinfection system. Might these systems achieve parity with hydrogen peroxide disinfection, but in a more convenient and material-appropriate way? Time will tell, but there is cause for optimism.
The Generic Problem
Generic, or more appropriately termed “store brand,” solutions should not be considered equivalent to, or an appropriate substitution for, branded contact lens care systems.12
To some patients, generics appear more cost-effective, especially when they are available to be purchased in bulk. Adding to the confusion is that the same major manufacturers of contact lens solutions often supply most of the generic brands, so it is easy to believe the two are interchangeable. However, the store brands are often older versions of branded solutions with significant differences in chemical make-up, including key preservative changes. Store brands will typically keep the same name and label appearance from year to year even if they change producers—and, thus, the chemistry of the solution itself. Unless consumers compare the package inserts, most do not know what formulation of solution they are actually using when they purchase a generic or store brand contact lens solution.
In an ideal world, a multipurpose contact lens solution would kill all resistant organisms while minimizing corneal toxicity and providing patients with all-day comfort.13 While we continue to struggle with patient noncompliance and microbial resistance, new technology gives our patients a fighting chance.
Today’s available solutions—Biotrue, Opti-Free PureMoist, and RevitaLens OcuTec—have all demonstrated their compatibility with silicone hydrogel lenses. Informing our silicone hydrogel contact lens wearers about the benefits of the newest multipurpose solutions available will maximize corneal health and comfort, and minimize contact lens dropouts.
Dr. Brafman is the co-director of Contact Lens Specialty Services at North Suburban Vision Consultants, Ltd.
Dr. Eiden is the president and medical director of North Suburban Vision Consultants, Ltd.
Dr. Harthan is currently an attending optometrist and an assistant professor at the Illinois Eye Institute.
Dr. Press is the director of Pediatric Eye Care, Binocular Vision and Vision Therapy Services at North Suburban Vision Consultants, Ltd.
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