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The following is a curated review of key information and literature about this topic. It is not comprehensive of all data related to this subject.
Overview
The eyes, mouth, and nose all contain mucosal surfaces that are potential routes of acquisition of SARS-CoV-2 due to the presence of the ACE2 receptor (the receptor that SARS-CoV-2 uses to enter the body). In healthcare settings, where reliable physical distancing may not be possible and workers may be exposed to individuals with SARS-CoV-2 infection, including those who are asymptomatic or presymptomatic, CDC recommends the use of eye protection such as face shields during patient care encounters.
In community settings, social distancing and the use of face masks are important mitigation strategies to reduce the transmission of SARS-CoV-2 (Moriarty, March 2020; Kimball, March 2020; Wei, April 2020; He, April 2020), but whether such protection is needed in community settings is not known. For information on masking for the public, please see the Masks and Face Coverings for the Public section.
Current data on eye protection to prevent SARS-CoV-2 transmission is limited to extrapolation of data of other respiratory viruses, animal studies, and studies examining the detection of SARS-CoV-2 in the conjunctiva (Marra, June 2020).
Here we describe data on the use of eye protection to prevent transmission of SARS-CoV-2; for additional information on transmission prevention in the healthcare setting, including a discussion of the potential routes of SARS-CoV-2 transmission, please see the Personal Protective Equipment in Medical Settings section.
Key Literature
In summary: Current data on the utility of eye protection in preventing acquisition of SARS-CoV-2 infection is based on observational studies, which suggest eye protection may provide added benefit to face masks in preventing the acquisition of SARS-CoV-2. Clinical studies of the efficacy of eye protection, particularly in the community, are warranted.
Association of Daily Wear of Eyeglasses With Susceptibility to Coronavirus Disease 2019 Infection (Zeng, September 2020).
- 276 patients hospitalized with COVID-19 in China.
- Most patients were moderately ill, with 14 (5.1%) severely ill.
- The association of the daily wearing of eyeglasses for > 8 hours and the susceptibility to COVID-19 were assessed.
- 155 (56.2%) patients were male, and the median age was 51 (interquartile range, 41-58) years. Underlying disease was present in 88 patients (31.9%), with hypertension the most common, accounting for 47 (17.0%) of all admitted patients.
- 30 patients with COVID-19 wore eyeglasses (10.9%), including 16 cases of myopia and 14 cases of presbyopia.
- All 16 patients with COVID-19 who wore glasses for more than 8 hours/day had myopia, accounting for 5.8% (95% CI, 3.0%-8.6%), and the median age was 33 years.
Adding eye protection to universal masking reduces COVID-19 among frontline emergency clinicians to the level of community spread (Hawkins, August 2020).
- Retrospective multicenter study in 14 EDs across a large Midwest integrated healthcare system with >500,000 ED visits annually.
- Assessed the efficacy of goggles by 352 frontline emergency clinicians (physicians and physician assistants) in conjunction with universal masking over a 4-month period.
- 14% (4/352) frontline ED clinicians contracted COVID-19, as compared to 0.85% residents of the county (p= 0.55).
- The authors note COVID-19 infection occurred among ED clinicians at a rate more comparable to community spread than to the prevalence in the ED patient population.
Observational study of the transmission of SARS-CoV-2 among community health workers before and after the use of face shields (Bhaskar, August 2020).
- Community health workers in a research network in India counseled and tested asymptomatic family contacts of persons with diagnosed COVID-19. They did not have exposure to each other and did not go home or to public places.
- The community health workers were masked and practiced social distancing while engaging with family members. They were tested for SARS-CoV-2 weekly.
- Before face shields, 62 workers visited 5880 homes, in which 222 people had positive RT-PCR tests. Twelve healthcare workers (19%) were infected during this time.
- After face shields, 50 workers visited 18,228 homes. 2,682 who were tested were positive. No healthcare workers were infected during this time.
- This was a retrospective observational study, so the findings may be limited by confounding factors.
A systematic review and meta-analysis of physical distancing, face masks, and eye protection to prevent transmission of SARS-CoV-2 (Chu, June 2020).
- Review of 172 observational studies in healthcare and non-healthcare settings of > 20,000 patients with COVID-19, MERS, or SARS.
- Eye protection was associated with a lower risk of infection (n=3713; adjusted odds ratio 0.22, 95% CI 0.12-0.39)
- The primary studies on eye protection in this meta-analysis were of low-certainty evidence.
Systematic review of articles on the ophthalmologic aspects of COVID-19 (Siedlecki, May 2020).
- This review noted that several studies have detected SARS-CoV-2 RNA via RT-PCR in tear film and the conjunctiva.
- These findings do not prove transmission via the eye, as the presence of RNA could reflect spread of the disease from the nasopharynx.
- They do raise concerns that the eye may be a portal of infection, particularly because ACE-2 receptor, which SARS-CoV-2 uses to enter the body, is present in the conjunctiva (Sun, April 2020).
Preprint animal study examining routes of acquisition of SARS-CoV-2 in rhesus macaques (Deng, March 2020).
- 5 macaques were inoculated with SARS-CoV-2 via different routes.
- The 2 macaques who underwent conjunctival inoculation developed symptoms of COVID-19 respiratory infection and had detectable SARS-CoV-2 RNA in the conjunctiva.
Retrospective cohort study during the 2003 SARS-CoV Toronto outbreak of risk factors for transmission between patients with SARS and healthcare workers (Raboud, May 2010).
- Study included 45 patients in Toronto with SARS-CoV who required intubation and were cared for by 697 healthcare workers, of whom 624 (90%) also participated.
- In multivariate logistic regression models, unprotected eye contact with secretions was associated with increased risk of transmission of SARS-CoV (OR = 7.34, p = .001).
- This study was limited by a retrospective design and the use of post-event interviews, which could have introduced recall bias into the results.