Daily wearers of eyeglasses less susceptible to COVID-19: JAMA
Coronavirus disease 2019 (COVID-19), the pathogen of which is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly infectious disease. COVID-19 has been proven to be transmitted mainly through droplets and contact. The eye is also considered an important route of infection.
Since the outbreak of COVID-19 in Wuhan in December 2019, the researchers observed that few patients with eyeglasses were admitted in the hospital ward. Therefore, Weibiao Zeng conducted a study to establish the association between the daily wearing of eyeglasses and the susceptibility to COVID-19.
This cohort study enrolled all inpatients with COVID-19 in Suizhou Zengdu Hospital, Suizhou, China, a designated hospital for COVID-19 treatment in the area, from January 27 to March 13, 2020. COVID-19 was diagnosed according to the fifth edition of Chinese COVID-19 diagnostic guidelines. Exposure included daily wearing of eyeglasses for more than 8 hours.
A total of 276 patients with COVID-19 were enrolled in the study. The median age was 51 years; 155 patients (56.2%) were male and 121 (43.8%) were female. Most patients with COVID-19 were moderately ill, with 14 (5.1%) severely ill.
Thirty patients with COVID-19 wore eyeglasses (10.9%), including 16 cases of myopia and 14 cases of presbyopia. None of the patients in this study wore contact lenses or underwent refractive surgery.
All 16 patients with COVID-19 who wore glasses for more than 8 hours per day had myopia, accounting for 5.8% and the median age was 33 years. Their symptoms, underlying disease, and COVID-19 severity were not significantly different from those of other patients.
The main finding of the study was that patients with COVID-19 who wear eyeglasses for an extended period (>8 h/d) every day were relatively uncommon, which could be preliminary evidence that daily wearers of eyeglasses are less susceptible to COVID-19. Considering the prevalence of COVID-19, conducting a sample survey among the local population would have been difficult.
Studies have shown that normal people will involuntarily touch their eyes about 10 times per hour. Eyes usually lack protection, and an abundance of the SARS-CoV-2 receptor angiotensin converting enzyme 2 has been found on the ocular surface, through which SARS-CoV-2 can enter the human body.
SARS-CoV-2 may also be transported to the nasal and nasopharyngeal mucosa through continuous tear irrigation of the lacrimal duct, causing respiratory infection. According to available statistics, nearly 1% to 12% of patients with COVID-19 have ocular manifestations, SARS-CoV-2 was detected in tears or the conjunctival sacs of patients with COVID-19, and some ophthalmologists were reported to be infected during routine treatment. Therefore, the eyes are considered an important channel for SARS-CoV-2 to enter the human body.
For daily wearers of eyeglasses, who usually wear eyeglasses on social occasions, wearing eyeglasses may become a protective factor, reducing the risk of virus transfer to the eyes and leading to long-term daily wearers of eyeglasses being rarely infected with COVID-19. Presently, many COVID-19 guidelines state the need to pay attention to preventing infections through the eyes, but most people only focus on wearing masks and home isolation, ignoring recommendations such as washing hands frequently and avoiding touching the eyes with the hands.
Limitations of the study:
First, it was a single center study with a small sample size. The numbers of patients who wear eyeglasses and long-term wearers were limited, which limits the extension of the results to a larger population.
Second, the proportion of wearers of eyeglasses was based on data from previous literature and was not calculated from current local populations.
Third, the myopia rate obtained in previous studies included a small number of people with myopia who did not wear eyeglasses. Information on these people was lacking and partly affected the integrity and validity of data.
Fourth, none of the research participants wore contact lenses, so the association between wearing contact lenses and susceptibility to COVID-19 remains to be studied.
The researchers found that the proportion of inpatients with COVID-19 who wear eyeglasses for extended daily periods was lower than that of the general population, suggesting that daily wear of eyeglasses is associated with less susceptibility to COVID-19 infection.
These findings suggest that the eye may be an important infection route for COVID-19, and more attention should be paid to preventive measures such as frequent hand washing and avoiding touching the eyes. In addition, further studies are needed to clarify the reasons that wearing eyeglasses may decrease susceptibility to COVID-19.
Source: Weibiao Zeng ; Xiaolin Wang ; Junyu Li; JAMA Ophthalmol. 2020;138(11):1196-1199.