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For cleaning soft contact lenses with multipurpose disinfection solutions, the "rub and rinse" technique is most effective for eliminating micro-organismseven when using "no-rub" disinfection solutions, according to a report in the August issue of Optometry and Vision Science, official journal of the American Academy of Optometry.
"'Rub and rinse,' in conjunction with soaking of the lens, is the most effective regimen to recommend with all the multipurpose lens care solutions used with any type of contact lenses," according to the new study, led by Hua Zhu, PhD, of Brien Holden Vision Institute in Sydney, Australia.
The researchers compared three regimens for soft contact lenses for cleaning with multipurpose disinfection solutions: "rub and rinse," a few seconds of rubbing and rinsing before soaking for several hours; "rinse-only," with no rubbing step; and "no rub and no rinse," or soaking only. The three techniques were used with commercially available multipurpose disinfection solutionsincluding newer solutions marketed as "no-rub" products.
The tests were performed using commercially available soft contact lenses, including two types of silicone hydrogel lenses. Various combinations of cleaning technique, disinfection solution, and lens type were compared for effectiveness in removing cultured bacteria, yeast and mold cells.
With all tested disinfection solutions, germ removal with multipurpose disinfection solutions was more effective when "rub and rinse" was performed before soaking. In contrast, the "no rub and no rinse" technique resulted in more microorganisms remaining on the lenses.
With the "rinse-only" technique, more germs were eliminated when disinfection solutions containing Polyquad preservative were used, compared to solutions containing a different preservative (polyhexamethylene biguanide). "Rinse-only" was less effective in eliminating micro-organisms from one of the two types of silicone hydrogel lenses tested (galyfilcon A)
Modern multipurpose disinfection solutions are designed to simplify the process of caring for soft contact lenses. When these solutions were introduced, the standard instructions were to manually rub and rinse the lenses before soaking them overnight.
More recently, "no-rub" solutions were introduced to further simplify contact lens care, and now dominate the market. However, eliminating the rubbing step may leave more germs behind. "Once adhered to a surface, microorganisms can become less susceptible to disinfection," the researchers write. The new study is the first to compare the effectiveness of the "rub" and "no-rub" techniques for disinfection of silicone hydrogel lenses with multipurpose disinfection solutions.
The results suggest that "rub and rinse" is the most effective technique, in conjunction with multipurpose disinfection solutions, for removing microorganisms from soft contact lenses. That's the case for all multipurpose disinfection solutions testedincluding those marketed as "no-rub" solutions.
The "rub and rinse" technique is also most effective for all types of contact lenses tested, especially silicone hydrogel lenses. "We believe this step, when used with any multipurpose disinfection solution, will promotelens disinfection against all types of microorganisms, and subsequently prevent colonization of the eye by pathogenic organisms, thus providing protection to contact lens wearers," according to Zhu and coauthors.