In addition to covering your face with a mask, will you soon need to wear glasses to protect yourself from the Covid-19 virus? Several studies show that those who wear glasses are less likely to be infected, and as a result, US health authorities are making recommendations.
When a team of Chinese researchers began analyzing data from patients admitted to the hospital for the coronavirus, they made a strange observation: very few patients were wearing glasses. Of 276 patients, only 16 (5.8%) had vision problems that required glasses for more than eight hours a day, according to the study published in JAMA Ophthalmology.
This is much lower than the average proportion of glasses wearers in the general population (31.5% in Hubei province). A quick conclusion of this study is that glasses offer protection against coronavirus, especially since another study published in May in The Lancet corroborates these figures. It establishes that eye protection (visor or glasses) is associated with a lower probability of infection (6 vs. 16% without protection).
In theory, the virus can enter the body through all mucous membranes of the face (mouth, nose, eyes). In fact, it should be noted that healthcare professionals in hospitals often wear face shields.
The eyes, a point of entry for the coronavirus
However, the main entry route of the virus remains the nose, due to the large number of receptors within the nasal mucosa that create a favorable environment for the implantation and replication of the virus, as well as a direct route to the lungs. Still, some patients have ocular symptoms of Covid-19, such as conjunctivitis or red eyes, which means that the virus can affect the eyes. It is believed that conjunctivitis is associated with the disease in 10 to 15% of cases, according to Carlos Solarte, associate professor at the University of Alberta. However, it is not clear if the eye is the gateway in this case.
Is it then necessary to impose the use of glasses in addition to the mask? We must be careful not to jump to conclusions. First of all, a correlation is not a cause and effect relationship. Other factors may be involved; for example, people wearing glasses tend to be older and so take more precautions in general. They are also less likely to rub their eyes with contaminated hands, which reduces the chances of infection.
A study conducted in 2015 shows that people touch their faces on average 23 times per hour, with 27% of participants touching their eyes (however, the study makes no distinction between eyeglass wearers and other people). “It would be wrong to conclude that wearing glasses reduces a person’s likelihood of getting Covid-19 or recommending the use of eye protection in public,” writes Lisa Maragaki, an infectious disease specialist at Johns Hopkins Medical School, in a comment accompanying the study.
Imposing the use of eyeglasses like the mask
This is the recommendation of Anthony Fauci, the White House advisor on the US coronavirus crisis: “It is not yet unanimously recommended, but if you want perfect protection, then you have to wear glasses or a face shield,” he explained in August during a Q&A session on ABC News.
To be sure that the eyes are an actual gateway for coronavirus, it would be necessary to be able to test the eye fluid from infected patients. However, most people have little fluid in their eyes, which makes this type of testing difficult and uncomfortable. However, it is not essential to have undeniable scientific evidence to impose a sanitary measure: the use of an outdoor mask is mandatory in several large cities, although no scientific studies have even been conducted to prove outdoor contamination.