In a JAMA Ophthalmology article published September 16, researchers note that, despite eyeglasses being commonly worn among the Chinese population, few patients admitted to the hospital for COVID-19 wore glasses.¹ This sparked an investigation that ultimately suggests that habitual spectacle wearers are less likely to be infected with the SARS-CoV-2 virus.¹ Coverage in consumer media soon brought the news, and possible misinterpretations of it, to patients around the world.

The authors studied 276 patients hospitalized with confirmed COVID-19 in Suizhou, China, between January and March 2020. They identified the percentage of myopic patients who were habitual glasses wearers in this hospitalized population, generalizing that myopes are more likely to wear glasses all day long, while presbyopes and hyperopes may set their glasses aside more frequently, especially in social settings.¹

They found that the rate of glasses-wearing myopes among confirmed COVID-19 patients was extremely low, at 5.8%. The authors compared this to an epidemiological study from 1987 that found the prevalence of myopia in a different province in China was 31.5%, and noted that in some more recent reports the prevalence in China exceeds 80%. They concluded that wearing eyeglasses more than eight hours a day may be protective against this virus.¹

This unique study suggests glasses may be a successful barrier to the virus. Despite the promising finding, reality, as always, is more complex. Several experts have pointed out issues with the study, including its small sample size, the poor comparison study, the possibility of other confounding variables (e.g., education, lifestyle, age or some other unknown variable) and that the study was conducted before the importance of hand-washing and social distancing was well-known.²

JAMA Ophthalmology ran an invited commentary on the study by Lisa Maragakis, MD, an infectious disease specialist at Johns Hopkins University School of Medicine; Dr. Maragakis commented that “the observed difference […] is unlikely to have occurred by chance alone, but it does not indicate a causal relationship between wearing eyeglasses and preventing the disease.”²

The mechanism by which glasses protect against the virus could include preventing aerosol access to the conjunctiva and decreasing hand-to-eye touching. We know that the SARS-CoV-2 can cause conjunctivitis and that the virus is present on the conjunctiva and in ocular secretions.³ The presence of the virus in the permeable barrier of the conjunctiva strongly suggests that it can also be transmitted through the mucous membranes of the eye, although researchers believe this is a rare form of transmission.⁴

Since the death of the ophthalmologist Li Wenliang on February 7, in Wuhan, China, after conducting an exam on an asymptomatic but infected glaucoma patient, we have known that eye care providers are at risk.⁵ The CDC recommends eye care providers wear a surgical mask and eye protection during all exams.⁶

This recent study is certainly provocative, and the question of the extent of barrier protection afforded by glasses deserves further investigation. For now, we should not let controversy over glasses distract us from what we know works: universal masking, physical distancing and frequent and vigorous hand-washing.

Dr. Kuhn-Wilken is a staff optometrist at Pacific & Laser Institute in Tacoma, WA.

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