Protection Goes Beyond Masking

By Brianne N. Hobbs, OD, 12/16/2020 from Medscape.com

Given that COVID-19 cases and deaths continue to climb, it’s clear that we don’t perfectly understand all modes of transmission, including the role of the eyes.
The eye, like the nose and mouth, is a mucous membrane that might serve as a portal for acquisition of SARS-CoV-2 by providing a large surface area exposed to droplets or airborne particles and contamination from a person’s hands. The surface of the eye is thought to contain SARS-CoV-2 ACE receptors, which bind to the virus. The virus has been isolated in tears and other conjunctival secretions, and like other viruses, it can be carried down via the nasal-lacrimal duct into the nasopharynx and into the lungs. Moreover, conjunctivitis can be the presenting sign of COVID-19.

Which of the many available eyewear options significantly reduce the risk for viral transmission? Let’s review the evidence.

Prescription Eyeglasses

Early in the pandemic, doctors in China made a curious observation about COVID-19 patients admitted to their intensive care unit. Very few of these patients routinely wore prescription eyeglasses, suggesting that glasses might have a role in protecting the wearer from the virus that causes COVID-19. Their observations were confirmed in a cohort study of patients admitted to the hospital with a diagnosis of COVID-19. Inpatients with COVID-19 were significantly less likely than the general population (5.8% vs 31.5%, respectively) to wear glasses for at least 8 hours daily. 

This significant disparity suggests a protective effect of full-time eyeglass wear against the acquisition of SARS-CoV-2, possibly by serving as a barrier to droplet and ocular surface transmission if worn when directly interacting with others. The findings of this small study, while certainly intriguing, are far from conclusive, and a prospective study would be needed to prove that glasses can guard against COVID-19.

Standard eyeglasses protect only the front of the eye, so airborne viruses, droplets, or splashes can reach the eyes from the top, bottom, or sides of the glasses. Poorly fitting or loose glasses might encourage more handling of eyewear, with potential contamination from the wearer’s hands.

Safety Glasses

Like standard eyeglasses, safety glasses (also known as trauma glasses) provide a relatively low level of protection against respiratory droplets. Safety glasses are primarily designed to protect the wearer from high-velocity impact and exposure to radiation and chemicals. The American National Standards Institute (ANSI) regulates the standards for this type of eyewear, with ANSI Z87.1 being the standard rating for eye and face protection. Note, however, that this rating does not include protection against bloodborne pathogens or other types of infection control.

Like prescription eyeglasses, many safety glasses are designed with gaps between the frame and the face, which may fail to block transmission of infection through sprays, splashes, or airborne particles circulating in poorly ventilated environments. This exposure point can be minimized with side shields or a wraparound design.

Plano safety glasses can be worn over prescription glasses and will probably provide some protection. Some safety glasses can be customized with prescription lenses to eliminate the need for multiple pieces of eyewear.

Goggles

By creating a seal around the eyes, goggles can dramatically reduce the access of the virus to the ocular surface by offering protection against sprays or splashes of respiratory droplets.
This effectiveness may depend on the style of the goggles. Goggles are available with different degrees of ventilation, which cuts down on fogging. Direct-vented goggles allow unimpeded airflow and also may allow penetration by sprays and splashes. Indirect-vented goggles may block liquid splashes but could still allow small airborne particles to penetrate. Nonvented goggles offer the highest level of infection by blocking airborne particles as well as sprays or splashes.
Some goggles can fit over prescription glasses, but it is important to check for any gaps between the edge of the goggles and the face.
Goggles are currently recommended for providers interacting with COVID-19 patients or working in areas with moderate to substantial SARS-CoV-2 transmission. Typically a nondisposable item, goggles should be removed after leaving an infected patient’s room, and cleaned and disinfected prior to next use. In areas with minimal or no community spread, goggles are considered optional unless otherwise indicated.
Unvented goggles (along with a face mask) would probably also offer the highest level of protection for anyone spending a long period of time with people in a poorly ventilated environment.

Contact Lenses

Questions have been raised about whether contact lenses can act as a shield against the transmission of SARS-CoV-2. On the flipside, there are fears that contact lenses could serve as reservoirs for the virus. Contact lenses could also potentially promote the spread of SARS-CoV-2 by increasing the frequency and intensity of hand contact with the ocular surface. t is unlikely that contact lenses offer any meaningful protection from infection because they are covered by the tear film, which is the eye’s first line of defense. Soft contact lenses more fully cover the cornea than hard lenses and thus might serve as a mechanical barrier to the eye’s SARS-CoV-2 ACE 2 receptors. However, the receptor density is low overall, and the tear film could still spread virus particles to the cornea and conjunctiva.
Nor is it likely that contact lenses play a significant role in promoting the spread of the virus as long as standard contact lens hygiene practices are followed. Contact lens wearers do tend to rub their eyes more often than the general population, which might serve as another route of infection of the eyes.
Patients with COVID-19 should refrain from wearing contact lenses while sick. Any soft contact lenses worn when the patient was positive for the virus should be discarded; hard contact lenses should be sterilized. There is no compelling evidence regarding specific contact lens materials and virus susceptibility, but in general, daily disposable lenses are the most effective at reducing inflammatory complications.

Choosing Eye Protection

Formal eye protection recommendations have been made for HCPs who are caring for COVID-19 patients in clinical settings, but other scenarios fall into a gray area.
If ventilation of the area is a concern or the level of ventilation in one’s workspace is unknown, then goggles would provide the highest level of eye protection, as they protect from airborne particles that may circulate for longer in a poorly ventilated area.
When interacting with other people where the level of contact is casual and social distancing is followed, eyeglasses or safety glasses would provide some level of eye protection from an unexpected sneeze or cough that could transmit SARS-CoV-2. The level of protection offered by eyeglasses or safety glasses is not robust, but they do provide at least some barrier to viral transmission.

Best Practices for Eyewear Removal

When eyeglasses or safety glasses are removed, the wearer should touch only the portion of the glasses that secures them to the head. The front of the glasses is the area most likely to be contaminated, so touching that area should be avoided. Safety glasses should be disinfected according to the manufacturer’s instructions and allowed to air-dry.

Goggles should be removed by touching the back strap, not the front or sides of the goggles.

The Evolving Role of Eye Protection

The precise role of eye protection is evolving. Although goggles and face shields provide high levels of eye protection from SARS-CoV-2 in the workplace, the evidence is less clear when it comes to safety glasses, standard eyeglasses, and contact lenses. Future studies will certainly attempt to determine the most effective form of eye protection for HCPs in the clinical setting.
In addition to HCPs facing an obvious risk for exposure to the virus and more severe COVID-19 illness in the workplace, recent evidencesuggests that the risks are also significant during social or family gatherings.
There is no question that the eyes pose a risk, at least theoretically, of serving as a gateway for infection with SARS-CoV-2, and they may even exhibit conjunctivitis, a presenting sign of the virus. In the absence of universal recommendations for protective eyewear during the pandemic, clinicians must decide for themselves how much protection they desire, both inside and outside the healthcare setting.
About the author: Brianne N. Hobbs, OD, is associate director of exam innovation at the National Board of Examiners in Optometry in Charlotte, North Carolina. She is currently engaged with the creation of a new clinical skills exam for optometry. She has spent most of her career in academia and has also worked in a hospital-based setting.  Follow Medscape on Facebook, Twitter, Instagram, and YouTube.

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