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Alan G Kabat; In-Vitro Demodicidal Activity of Commercial Lid Hygiene Products. Invest. Ophthalmol. Vis. Sci. 2018;59(9):905.
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© ARVO (1962-2015); The Authors (2016-present)
Demodex folliculorum is a ubiquitous mite that infests the eyelash follicles, sometimes resulting in a clinical condition known as demodex-associated blepharitis (DAB). Two commercial lid hygiene products have asserted their effectiveness in killing demodex mites, yet there has not been a comparative study between these two products. This observational, in-vitro study evaluated the demodical activity of Avenova (NovaBay Pharmaceuticals, Inc) and Cliradex (BioTissue, Inc.) in comparison to a known, negative control (mineral oil).
Live demodex mites were obtained from volunteers who were selected for eyelash sampling based on the presence of cylindrical dandruff, a hallmark sign of DAB. Lashes were obtained at the slit lamp using forceps, and transferred to glass slides where they were immersed in 2-3 drops of test solution. Avenova, which contains 0.01% hypochlorous acid, Cliradex, which contains 4% terpinen-4-ol, and 100% mineral oil were applied. Counts were recorded as the number of live, adult mites per slide, and samples were observed under the microscope (40-100X magnification) every 10 minutes for up to 90 minutes. The kill time was defined as the elapsed time between the addition of test solution and all cessation of movement of the body, legs, mouth or pedipalps for a minimum of 60 seconds.
Cliradex demonstrated a mean kill time of 40±0.0 minutes. Avenova had a mean kill time of 88±4.3 minutes, with 79% of the samples surviving the full 90 minutes of observation. In the mineral oil group, all samples survived through the 90-minute mark. Kill time was statistically significant in favor of Cliradex as compared to Avenova (p = 0.0003). There was no statistically significant difference in kill time between Avenova and mineral oil (p = 0.25). Random, individual samples of Demodex folliculorum that survived beyond the 90-minute mark were observed for extended periods. The maximum survival time noted in Avenova was 210 minutes, while in mineral oil it was 1,470 minutes.
Cliradex effectively killed all adult mite samples within 40 minutes of exposure. In contrast, the demodicidal activity of Avenova was comparatively similar to the negative control, 100% mineral oil.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Left: Demodex-associated blepharitis with classic cylindrical dandruff (white arrows); Right: Demodex mites on a lash follicle (black arrows).
Maximum observed survival time with test solutions.
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