In this file photo, two people with glasses wear face masks as they shop at a market in Montreal, Sunday, Sept. 13, 2020, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes

Researchers in China have observed a curious link in one of the more specific COVID-19 studies to come out of this pandemic: hospitalized COVID-19 patients were less likely to wear glasses than the average population.

A new study, the results of which were published Wednesday in the journal JAMA Ophthalmology, found that there was a smaller proportion of glasses-wearers out of a sample of COVID-19 patients at a hospital in China, than the percentage of glasses-wearers in the general population.

"Wearing of eyeglasses is common among Chinese individuals of all ages,” the study stated. “However, since the outbreak of COVID-19 in Wuhan in December 2019, we observed that few patients with eyeglasses were admitted in the hospital ward.”

Researchers looked at 276 COVID-19 patients admitted to Suizhou Zengdou Hospital between Jan. 27 and March 13, and found only 16 had myopia and thus generally wore glasses more than eight hours a day.

Myopia is the official term for nearsightedness, which is one of the most common reasons that people wear glasses. Those who are nearsighted are able to see things close to them clearly, but see objects that are farther away as blurry.

According to a previous 1985 study of the general population in the Hubei province of China, the average rate of myopia among students aged 7-22 years in that region was 31.5 per cent. Those same students would now be 42 to 57 years old, the study pointed out, “which is close to the median age of our patients with COVID-19.”

But this new study of COVID-19 patients found that only 5.8 per cent of those hospitalized with the virus wore glasses, a far lower percentage than 31.5 per cent.

It’s important to note that this is an observational study, not one looking for causation.

There’s no reason to believe that wearing glasses protects against COVID-19, or that being blessed with perfect vision also makes you more susceptible to COVID-19.

The researchers also acknowledged that the data from the previous 1985 study could have impacted the results because “the age, region, and educational level of the students in that survey had some differences compared with our study population.”

The results, the study suggested, may come down to human behaviour, not any inherent, virus-fighting sheen on the average pair of glasses.

The researchers hypothesized that wearing glasses might have prevented some spread of the virus due to the glasses discouraging “wearers from touching their eyes, thus avoiding transferring the virus from the hands to the eyes.”

They noted that previous research has shown that the enzyme that SARS-CoV-2 (the virus that causes COVID-19) uses as a receptor is in abundance on the surface of the eye.

“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,” the study stated.

So while this new research doesn’t mean you need to go out and buy the widest pair of sunglasses possible, it might be a sign that you should be a little more careful about not touching your eyes after you readjust your mask.