A team of scientists from China suggests that people who wear eyeglasses for more than 8 hours a day may be less susceptible to infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study is published recently in the journal JAMA Ophthalmology.
SARS-CoV-2, a highly infectious and deadly virus responsible for coronavirus disease 2019 (COVID-19), is known to spread from person to person via respiratory droplets. The major routes of viral transmission include nose, mouth, and eye.
In China, more than 80% of the population has myopia, which is a vision disorder making distant objects blurry. As a therapeutic intervention to correct the vision, the majority of Chinese people wear eyeglasses. However, since the emergence of the COVID-19 pandemic in China, it has been noted that the prevalence of SARS-CoV-2 positive patients in hospitals is very low.
This observation encouraged the current study scientists to analyze if there was any association between wearing eyeglasses and COVID-19 risk.
Current study design
The study involved a total of 276 COVID-19 patients who were admitted to Suizhou Zengdu Hospital, China, between January 27 and March 13, 2020. The average age of the study participants was 51 years (age range: 41 – 58 years), and about 56.2% of them were male. About 5.1% of the patients had a severe form of COVID-19.
To fully document eyeglasses wearing habits, patients were asked about the reason for wearing eyeglasses, daily duration of wearing eyeglasses, and information about wearing contact lenses or having refractive surgery. The patients who wore eyeglasses for >8 hours daily were considered long-term wearers. The scientists considered that these people wear eyeglasses when staying outdoor and socializing with people.
To estimate the prevalence of myopia in the general population, the scientists collected the data from the Research on Chinese Student Physique and Health Study, which includes information about the health status of Chinese students in 1985.
The current study findings revealed that about 10.9% of COVID-19 patients wore eyeglasses; of them, 5.8% had myopia, and 5.1% had presbyopia (age-related weakening of near vision). The patients who had myopia (5.8%) were found to be the wearers of eyeglasses for more than 8 hours daily (average age: 33 years). None of the patients reported wearing contact lenses or having refractive surgery.
Regarding population statistics, a previous study published in 1987 has shown that about 31.5% of Chinese students aged 7 – 22 years had myopia. In the current study, the scientists estimated that by 2010, these students were in the age range of 42 – 57 years, which is similar to the age range of current study participants.
These observations indicate that in Suizhou, China (the study region), the prevalence of myopia in the general population (31.5%) is much higher than that in COVID-19 patients enrolled in the study (5.8%), suggesting that people who wear eyeglasses may be less likely to acquire SARS-CoV-2 infection.
How may eyeglasses provide protection?
Evidence shows that people who do not wear eyeglasses involuntarily touch their eyes around ten times per hour. Wearing eyeglasses prevent people from frequently touching their eyes, thereby reducing the chance of hand-to-eye transmission of SARS-CoV-2.
According to the published literature, about 1 – 12% of COVID-19 patients display ocular characteristics, such as the presence of SARS-CoV-2 in tears or the conjunctival sacs. Mechanistically, SARS-CoV-2 can enter the human body by binding to angiotensin-converting enzyme 2 (ACE2), which is highly abundant on the ocular surface. Therefore, it is likely that wearing eyeglasses may have a protective effect by reducing the chance of viral entry through the eyes.
The current study findings highlight the fact that to effectively contain the spread of SARS-CoV-2, people should practice all the recommended control measures such as frequently washing hands and avoiding touching eyes with hands, in addition to wearing masks, maintaining social distancing, and following home isolation rules.