Rubbing and rinsing regimen important for removal of coronavirus from contact lens materials

A new study by the University of Waterloo’s Department of Chemical Engineering and the Center for Ocular Research & Education (CORE) has determined that human coronaviruses can easily be cleared from contact lens surfaces, although diet is important depending on the type of lens care solution. Specifically, the scrubbing and rinsing steps are crucial for non-oxidizing systems, while products containing hydrogen peroxide and povidone-iodine remove contaminants by soaking alone.

The impact of a rub and rinse regime on the removal of human coronaviruses from contemporary contact lens materials (Nogueira C, et al) is in press from Contact Lens and Anterior Eye, the peer-reviewed journal of the British Contact Lens Association.

Although an ocular route has not been shown to be a primary route of entry for SARS-CoV-2, the ongoing COVID-19 pandemic has raised awareness of the physical transmission of the virus through the hands and fingers. However, there is little data regarding the attachment of viruses, particularly coronaviruses, to lens materials and the ability of contemporary contact lens care products to inactivate them.

To assess attachment links, researchers selected two seasonal human coronaviruses, HCoV-229E and HCoV-OC43 as surrogates for SARS-CoV-2, allowing less pathogenicity while being in the same virus family with similar structures. . Eight soft contact lens materials (including silicone hydrogels and hydrogels) and four RGP contact lens base materials (with and without hydrophilic coating) were contaminated and then soaked in phosphate-buffered saline solution. Although virus particles were recovered when the lenses were removed from passive saline soaking, no detectable virus remained when the lenses were subjected to single rinse, double rinse, or rub and rinse treatments. .

Since a simple saline rinse step alone removed both virus types from all materials, two representative soft lens materials (a hydrogel and a silicone hydrogel) were chosen to evaluate the effectiveness of the system. of care for the elimination of HCoV-229E. The investigators selected four representative contact lens care products (two oxidizing and two non-oxidizing). Both oxidative disinfection systems reduced the number of infectious viral particles adhering to each material below the limit of quantification by dipping alone. Non-oxidative disinfection systems required a scrub and rinse step to do the same.

“Our results indicated that human coronaviruses bind quite loosely to contact lens materials, which should provide peace of mind to the eye care community and wearers, as long as proper care is provided,” said Lyndon Jones, PhD, DSc, FCOptom, a paper co-author and director of CORE. “Practitioners and manufacturers should continue to emphasize the importance of following disinfection regimens, particularly ensuring that a scrub and rise step occurs prior to overnight disinfection when using non-oxidizing systems. .”

The full article and additional data are available free of charge from Contact Lens and Anterior eye at https://doi.org/10.1016/j.clae.2022.101719

The study was funded by Ophtecs Corp.

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