Multipurpose solutions (MPSs) and hydrogen peroxide (H₂O₂) systems are designed to minimize the risks of reusable soft lens complications such as microbial keratitis (MK) (Stapleton, 2007). Each solution employs unique mechanisms to accomplish that goal. MPSs are effective for cleaning, disinfecting, and storing lenses. They contain disinfectants that disrupt microbial membranes, leading to cell death. They also contain buffering agents, preservatives, and surfactants for cleaning (Tichenor et al, 2020). Some potential disadvantages of MPSs that may affect outcomes include the use of chemical preservatives; biocompatibility issues; and challenges with lens care compliance (Nichols et al, 2019). One survey of 50 asymptomatic lens wearers asked participants about lens type, hygiene, wearing habits, lenses, and lens care system replacement schedule. Only two respondents (4%) were fully compliant soft lens wearers (Kuzman et al, 2014).

H₂O₂-based systems use 3% peroxide, which (with a catalyst disc or neutralization tablet) neutralizes into saline with an overnight soak of at least six hours. H₂O₂ disinfects lenses via oxidation, which acts on proteins, lipids, and microbial DNA (Holden, 1990). Because these systems are preservative-free, they are a practical option for patients who have allergies or sensitivities to preservatives (Nichols, 2018).

Even though H₂O₂ is safe and effective, the use of these care systems is low compared with MPS use (Nichols et al, 2019). One publication reported that just 8% to 10% of soft lens wearers use H₂O₂ to disinfect their lenses (Morgan et al, 2016). Another report suggested that peroxide use may be rising, with growth from 10% to 20% over the past 15 years (Jones et al, 2016).

Complication Comparison

One multicenter, retrospective study compared the frequency of lens complications in patients using MPS or H₂O₂ (Tichenor et al, 2020). Researchers reviewed reports from the last three eye examinations of 1,137 patients from two academic institutions and five private practices in the United States and Canada. To be included in the study, patients must have used the same type of care system for at least three years. They reported that MPSs were more commonly used (n = 670, 58.9%) compared to H₂O₂ (n = 467, 41.1%).

Sixty-two percent (706 patients) experienced at least one complication; of that group, 61% were using MPS and 64% were using H₂O₂ (P = 0.38). The most common complication was papillae (n = 311, 27.4%), followed by hyperemia (n = 242, 21.3%) and discomfort (n = 240, 21.1%). MPS users were more likely to report discomfort at least one time during the review period compared with H₂O₂ users (P = 0.04). These findings parallel those of other comparative studies that noted greater lens wettability (Guillon et al, 2015), longer comfortable lens wear per day (Keir et al, 2010), and improved comfort on lens application (Diec et al, 2013) with H₂O₂. Subjective comfort outcomes were not unequivocal (Lievens and Jones, 2019); however, there were no significant differences between H₂O₂ and MPS in comfort and dryness ratings (Keir et al, 2010), end-of-day comfort (Diec et al, 2013), comfortable wear time (Berntsen et al, 2016), and Contact Lens User Experience (CLUE) scores. MK was reported in 16 MPS and in nine H₂O₂ users (P = 0.60), which is 2% of all visits and about 1% per year. This rate of MK is higher than previously reported, possibly owing to misdiagnoses or to practitioners diagnosing microbial infection and prescribing an antibiotic without a confirmatory culture (Tichenor et al, 2020).

While there are no significant differences in the frequency of contact lens complications between the solutions, an H₂O₂ system may be an option for contact lens wearers who experience discomfort. CLS

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