Contact lens disinfection methods are still important
Long-term success of contact lens wearers attributed to education, professional input on cleaning methods
Common sense suggests that failure to properly clean contact lenses can lead to eye infection and inflammation.
Nevertheless, 99% of contact lens wearers admit to having at least 1 risky behavior when it comes to lens hygiene.1
Thus, eye care providers need to recommend the right lens sanitizer to their patients and impress on them the need to follow the instructions on the package exactly.
About 60% of patients still wear reusable lenses,2 and all-in-one systems appeal to them because of their convenience.
However, to ensure that these systems do not cause infections or inflammation, the lenses should be rubbed and rinsed.3 for > 10 seconds each time they are removed and the solution is never “completed”; instead, fresh solution should be added to the case before the lenses are stored.
Although there are many effective multi-purpose solutions,4 Comparing generic and brand name products can be difficult for eye care providers and consumers because they contain different preservatives and surfactants and their different mechanisms of action. Research leading to the approval of disinfecting agents for use in humans strictly adheres to package directions, and real-world safety depends on the same adherence. Unfortunately, most patients who use multi-purpose solutions say they don’t follow the above instructions.
Thus, the ease of use of multi-purpose solutions could rather be characterized as an abuse that compromises their effectiveness.
Different types of bacteria can also affect the performance of a sanitizer. For example, Pseudomonas aeruginosa adheres to the lens surface more than Staphylococcus aureus.4 Gram-negative organisms have greater resistance to microbicides than gram-positive organisms.4 Different surface coatings on the lenses can also affect their interaction with the disinfectant solution and the overall performance of it.
Most cleaning solutions contain similar basic ingredients. Phosphate buffered saline is prepared with mild antibacterial biocides such as polyaminopropyl biguanide, polyquaternium, polyhexamethylene biguanide, polyhexanide hydrochloride, polyquaternium-1, and myristamidopropyl dimethylamine.5 These biocides kill bacteria or disrupt bacterial adhesion to the lens surface.6
To reduce surface tension and increase surface moisture, each brand has a proprietary wetting agent that conditions the lens. Finally, multipurpose solutions contain preservatives like boric acid, sodium borate, and sodium chloride, which keep them sterile, but some patients may be sensitive to these preservatives or the concentrations used. For them, other disinfection methods are recommended.
Hydrogen Peroxide Solutions
These solutions are not used in the United States as frequently as the multi-purpose solutions, as they are only recommended by approximately 25% of eye care professionals in the United States.
However, as they are reported to have fewer complications,7–9 they may be recommended for patients who wear soft lenses, gas permeable contact lenses, hybrid lenses and scleral lenses, and for those who are sensitive to preservatives in multi-purpose solutions, who suffer from allergies or dry eyes , or who experience non-lens specific discomfort. A 2018 report found that peroxide solutions were superior to multipurpose solutions in terms of compliance, ease of use, disinfection effectiveness, comfort, and ocular surface safety.9
Originally introduced in the early 1970s, these systems dominated the market until the development of multi-purpose systems.8.10 There are 2 types of hydrogen peroxide (H2O2) products: a 2-step system that requires soaking the lenses in a 3% H2O2 solution overnight, then introducing a neutralizing agent 8.11 and the most common 1-step system that uses either a platinum disc or a time-release catalase tablet to neutralize the peroxide.
Today’s H2O2 products include surfactants that aid in the removal of deposits and the wettability of lenses,9 and they don’t contain preservatives, which can also improve their overall comfort compared to all-purpose solutions.8.12
H2O2 solutions are biocides that destroy bacteria, fungi and protozoa9 by producing free radicals that act as oxidizing agents, damaging the cell membranes of microorganisms and penetrating biofilms.ten
Before the lenses can be put on, the H2O2 solutions must be converted into water and oxygen by a neutralizer.13 Peroxidases are ocular surface enzymes that, with a normal blink, can metabolize H2O2 within 60 seconds and avoid damage to ocular surface cell membranes.13.14
Some eye care providers may be hesitant to recommend H2O2 systems due to concerns about lens care non-compliance.
However, a 2007 study reported that 37% of multi-purpose solution users reported compliance, while 100% of H2O2 users reported compliance when using the one-step system.15
Ultimately, patient education is the key to adherence. Patients should be instructed never to rinse lenses with H2O2 solution, never to use topical hydrogen peroxide sold in brown bottles on lenses, and to always leave lenses in H2O2 solution for the recommended length of time for a complete neutralization. Wearing contact lenses that are comfortable, long-term, and free of adverse effects depends on the patient’s compliance with their ophthalmologist’s recommendations and the instructions on the disinfectant package.
1. Cope JR, Collier SA, Rao MM, et al. Contact lens wearer demographics and risk behaviors for contact lens-related eye infections – United States, 2014. MMWR Morb Mortal Wkly Rep. 2015;64(32):865-870. doi: 10.15585/mmwr.mm6432a2
2. Morgan P, Woods CA, Tranoudis IG, et al. International contact lens prescriptions in 2019. Spectrum of contact lenses. 2020;35(January): 26-32.
3. Cho P, Cheng SY, Chan WY, Yip WK. Cleaning soft contact lenses: to rub or not to rub? Ophthalmic Physiol Opt. 2009;29(1):49-57. doi: 10.1111/j.1475-1313.2008.00606.x
4. Correa PC, Lui ACF, Silva CB, et al. Study of the efficacy of multi-purpose solutions on the bacterial disinfection of silicone hydrogel contact lenses in vitro. eye contact lens. 2018;44 Suppl 2(2):S24-S28. doi: 10.1097/ICL.0000000000000428
5. Gromacki, Susan J.; MA district. Understanding contemporary contact lens care products: an overview of current contact lens systems, their components, and standards for care and cleaning. Spectrum of contact lenses. 2013;28(June):20-25.
6. Khan M, Stapleton F, Willcox MDP. Susceptibility of contact lens-related pseudomonas aeruginosa keratitis isolates to multipurpose disinfectant solutions, disinfectants, and antibiotics. Transl Vis Sci Technol. 2020;9(5):2. doi:10.1167/tvst.9.5.2
7.Nichols JJ. Contact lenses 2016. Spectrum of contact lenses. 2017;32:22-25,27,29,55.
8. Chalmers RL. A new look at one-step hydrogen peroxide lens disinfection. Rev Optom. 2014; Supplement:1-8.
9. Nichols JJ, Chalmers RL, Dumbleton K, et al. The case for using hydrogen peroxide contact lens care solutions: a review. eye contact lens. 2019;45(2):69-82.
10. Lowe R, Brennan NA. Hydrogen peroxide disinfection of hydrogel contact lenses: an overview. 2021;70(6):190-197.
11. Jones L, Christie C. Soft Contact Lens Solutions Review: Part 2: Optom Pract. 2008;9:43-62.
12. Sindt CW. Contact Lens Solutions 101. Rev Cornea Contact Lenses. 2013:18-19.
13. Chalmers RL, McNally JJ. Ocular Detection Threshold of Hydrogen Peroxide: Drops vs Lenses. ICLC. 1988;15(11):351-357.
14. Chalmers RL. A review of hydrogen peroxide metabolism by the external ocular structures. Int Clin Contact Lenses. 1995;22(7-8):143-147. doi:10.1016/0892-8967(95)00038-V
15. Woods J, Jones L. Lens care compliance. Spectrum of contact lenses. 2019;34(April):36-40.