Saline solution removes human coronavirus from various contact lens materials

According to a new study in Contact lens and anterior eye.

“The ongoing COVID-19 pandemic has focused global attention on viral transmission and the importance of disinfection and viral load reduction,” Christiane Lourenco Nogueira, PhD, a postdoctoral fellow in chemical engineering at the University of Waterloo in Canada, and his colleagues wrote. “Even though ocular complications are not a common manifestation of coronavirus infections in humans, various studies have suggested that ocular exposure could represent a potential route of entry for SARS-CoV-2.

“Therefore, given that viruses can be transferred through physical contact through hands and fingers, it has been suggested that contact lens wearers are at higher risk of developing COVID-19 during application and lens removal.

With limited data on viral attachment to contact lens material and the potential for conjunctival transmission of SARS-CoV-2, Nogueira and colleagues sought to assess coronavirus attachment on a variety of contact lens materials. , as well as the effectiveness of cleaning by rubbing and rinsing. step in virus removal.

The researchers used two seasonal human coronaviruses – HCoV-229E and HcoV-OC43 – as surrogates for SARS-CoV-2 and analyzed eight unworn soft contact lens materials, which included conventional hydrogel and hydrogel silicone, and four GP contact lens materials. They also evaluated the effectiveness of Biotrue (Bausch + Lomb), Opti-Free Puremoist (Alcon), Clear Care (Alcon), and cleadew (Ophtecs) in removing viral contamination from two soft lens materials (etafilcon A and lotrafilcon B ).

After soaking in 4 mL of D-PBS overnight, four sets of each lens material were incubated in human coronavirus suspensions for 6 hours. Each set received a different treatment: no rinsing or rubbing (briefly soaked in 4 mL of D-PBS), rinse only (each side of the lens rinsed with 4 mL of D-PBS), rinsing twice (each side rinsed twice with 4 ml of D-PBS). -PBS), and rinse and scrub (each side rinsed with 4 mL of D-PBS, scrubbed in a circular motion with a 3D-printed gloved “finger,” and rinsed again with 4 mL of D-PBS).

According to the results of the study, about 10² at 10³ infectious virus particles were recovered from each lens material after treatment without rinsing or rubbing. Researchers reported no detectable virus after rinsing only, rinsing twice, and rinsing and scrubbing treatments.

Additionally, lens care products based on an oxidative disinfection system (Clear Care and cleadew) reduced the number of infectious viral particles that adhere to conventional hydrogel and silicone hydrogel materials, while non-oxidative disinfection systems ( Biotrue and Opti-Free Puremoist) were only able to do this when additional scrubbing and rinsing steps were included.

“The results of this study demonstrated that various CL [contact lens] the materials were also prone to adhesion of human coronaviruses, which can be easily removed from CL surfaces when scrubbed or rinsed only with saline,” Nogueira and colleagues concluded. “This study also demonstrated the importance of following CL care product disinfection regimens to remove infectious coronaviruses from CL surfaces that can potentially lead to human infections.”

They added: “The effectiveness of CL care products based on non-oxidative disinfection systems against the viruses under investigation can be improved by ensuring that a scrub and rinse step is used prior to overnight disinfection.