A smaller proportion of patients with COVID-19 reported wearing eyeglasses daily than the rate of myopia in the general population, suggesting a potential inverse relationship between glasses and contracting the virus, a small observational study in China found.
Approximately 5.8% of COVID-19 inpatients (95% CI 3.0%-8.6%) wore glasses for more than 8 hours a day, while the myopia rate in prior research was 31.5%, offering “preliminary evidence” that patients who wore eyeglasses may be less susceptible to COVID-19, reported Yiping Wei, MD, PhD, of the Second Affiliated Hospital of Nanchang University, and colleagues, writing in JAMA Ophthalmology.
So, does this mean everyone should wear eye protection, including a face shield, to prevent transmission of COVID-19? Not exactly, said an accompanying editorial by Lisa Maragakis, MD, of Johns Hopkins University in Baltimore, who cautioned not to infer “a causal relationship from a single observational study.”
Maragakis lists numerous caveats to the research, including that data for the general population comparison group was from a decades-old study in a different region of China, as well as confounding variables having nothing to do with wearing glasses. Moreover, since this study took place early in the pandemic (January 27 to March 13), there was no way to assess the impact of non-pharmaceutical interventions, such as face masks and hand hygiene.
Despite this, Maragakis offered a potential reason eyeglasses could provide some protection from the virus.
“They may serve as a partial barrier that reduces the inoculum of virus in a manner similar to what has been observed for cloth masks,” she wrote, citing a recent preclinical study on masks that found in addition to protecting others, “cloth masks may also reduce the viral inoculum that the mask wearer inhales and thereby contribute to lessening the severity of the disease that subsequently develops.”
Maragakis said this would mean there would be a stronger protective effect from goggles or a face shield, but future studies are needed to show that effect.
Wei and colleagues offered a biological explanation — namely that angiotensin-converting enzyme 2 is on the ocular surface, where SARS-CoV-2 can enter the human body. It may also be transported to “the nasal and nasopharyngeal mucosa through continuous tear irrigation of the lacrimal duct, causing respiratory infection.” Indeed, ocular manifestations of SARS-CoV-2 were reported, and the virus was detected in patient tears.
The researchers examined data from 276 inpatients with COVID-19 at a single medical center. Median age was 51, and 56% were men. Most patients were described as “moderately ill,” with 82% reporting fever and 79% reporting cough, while half reported fatigue. About a third had hypertension.
Overall, 10.9% of COVID-19 patients wore glasses, including 16 cases of myopia and 14 cases of presbyopia. No patients wore contact lenses or underwent refractive surgery, and all 16 patients who wore eyeglasses for 8 hours or more had myopia.
Prior research cited as comparison was a rate of myopia in students ages 7-22 in Hubei province. The researchers said the students would now be age 42-57, and that is “close to the median age” of COVID-19 patients. The investigators noted that the previous study also included a small number of people with myopia who did not wear eyeglasses, but information on these people was lacking, which “partly affected the integrity and validity of our data.”
Last Updated September 16, 2020
The authors disclosed no conflicts of interest.
Maragakis disclosed serving as co-chair of the CDC Healthcare Infection Control Practices Advisory Committee.