During the beginning of the COVID-19 pandemic, there were copious fallacies that contact lenses were not healthy or safe to wear. However, these were not evidence-based recommendations and were quickly falsified. There is currently no evidence to suggest that lens wearers are more at risk for acquiring COVID-19 compared to spectacle wearers (Jones et al, 2020).

That said, proper contact lens care and handling is undeniably essential. To avoid ocular SARS-CoV-2, there is a current worldwide emphasis on the importance of hand hygiene and avoidance of touching the face, mouth, and eyes (Jones et al, 2020). Proper hand washing for at least 20 seconds with soap and water and drying hands with a clean paper towel are important prior to applying or removing contact lenses.

Caring for contact lenses is equally important. For daily disposable lenses, throw them away after each wear. For reusable lenses, proper cleaning and disinfection is vital. With any illness, contact lens wear should be suspended until healthy again.

Lens Cleaning and Disinfection

Globally, daily wear with nightly disinfection is the most common contact lens wear schedule (Morgan et al, 2021); disinfection kills any microbes, including coronavirus, that may be contaminating the lenses after wear and prior to rewear. Lenses soaked in multipurpose disinfecting solutions (MPSs) can absorb excipients and impart antibacterial activity (Dutta et al, 2013; Morris et al, 2018).

According to the U.S. Environmental Protection Agency (EPA), hydrogen peroxide-based systems are effective against COVID-19 (https://www.epa.gov/coronavirus/about-list-n-disinfectants-coronavirus-covid-19-0 ). Within one minute, a 0.5% solution of hydrogen peroxide, which is significantly less than that used in contact lens disinfecting solutions (3%), can cause a > 4 log₁₀ reduction in coronavirus contamination (Kampf et al, March 2020; Kampf et al, June 2020). With a 0.23% concentration of povidone iodine, there was a > 4 log₁₀ reduction in coronavirus infectivity within 15 seconds (Kampf et al, March 2020).

A study by Yasir et al (2021) evaluated the antiviral potential of five MPSs against coronavirus. A mouse hepatitis virus, which is a surrogate for SARS-CoV-2 human coronavirus, was used. Solutions were mixed with the coronavirus mouse hepatitis virus at 104 plaque forming units (PFU)/mL as the absolute concentration and incubated at room temperature for a specific disinfection time. The remaining virus from each sample was quantified by standard PFU assay. Then, the reduction of PFU for each disinfectant was compared to a phosphate-buffered saline-treated negative control.

In the standalone test, three MPSs did not eradicate coronavirus at the manufacturers’ recommended disinfection time. A hydrogen peroxide solution and a povidone iodine solution both significantly (p < 0.001) reduced the numbers of coronaviruses to less than the detection limit. Additionally, there was a significant reduction (p = 0.028) in the number of coronaviruses attached to lenses with one of the MPSs that went through a regimen test. This study demonstrated that oxidative lens disinfecting solutions containing povidone iodine or hydrogen peroxide provide enhanced antiviral activity against a coronavirus surrogate of SARS-CoV-2.

This study established that a SARS-CoV-2 surrogate is unaltered when added directly to MPSs containing various surfactants and assorted mixtures and concentrations of the disinfectants polyaminopropyl biguanide, polyquaternium-1, and alexidine. The study authors recommend that contact lens practitioners should reiterate the need to rub and rinse lenses with multipurpose disinfecting solutions to reduce the number of coronaviruses on lenses. CLS

For references, please visit www.clspectrum.com/references and click on document #314.