Study published today in the journal of the American Academy of Ophthalmology found no virus in tears of infected patients
SAN FRANCISCO, Calif. – March 25, 2020 – While researchers are certain that coronavirus spreads through mucus and droplets expelled by coughing or sneezing, it is unclear if the virus is spread through other bodily fluids, such as tears. Today’s just-published study offers evidence that it is unlikely that infected patients are shedding virus through their tears, with one important caveat. No patient had conjunctivitis, also known as pink eye, at the start of the study. One patient did develop conjunctivitis during the study. The study’s authors conclude that their findings, coupled with the generally low incidence of pink eye among infected patients (believed to occur in just 1 percent to 3 percent of patients) suggests that the risk of virus transmission through tears is low. Their study was published online today in Ophthalmology, the journal of the American Academy of Ophthalmology.
To conduct the study, Rupesh Agrawal, MD, from Tan Tock Seng Hospital and Ivan Seah, MBBS from the National University Hospital worked with colleagues at the National Centre for Infectious Diseases to sample tears from 17 patients with COVID-19. These samples were collected from the time they showed symptoms until they recovered about 20 days later. Neither viral culture nor reverse transcription polymerase chain reaction (RT-PCR) detected the virus in their tears throughout the two-week course of the disease.
The team at the National Centre for Infectious Diseases also took samples from the back of the nose and throat during the same time period. While the patients’ tears were clear of virus, their noses and throats were teeming with COVID-19. The team hopes that their work will help to guide more research into preventing virus transmission through more significant routes, such as droplets and fecal-oral spread.
A commentary written by ophthalmologist not involved with this study notes some additional caveats:
- Only one of the study participants had conjunctivitis during sample collection.
- Most of the tear samples were taken at a time when the viral load is known to decrease precipitously; after two to three weeks of symptom presentation.
- The diagnostic sensitivity of samples taken from the eyes, such as tears and conjunctival swabs, is generally lower than for other tissue types due to the low sample volume. Therefore, a negative result may reflect insufficient tissue sampling. Additionally, the viral load in non-inflamed ocular tissues is likely to be low.
- A separate study conducted in China evaluated conjunctival swabs of 30 patients with COVID-19. Only one patient in this study presented with conjunctivitis and that patient’s tear sample tested positive.
Despite this reassuring news, it’s important for people to understand that guarding your eyes — as well as your hands and mouth — can slow the spread of respiratory viruses like the coronavirus.
- When a sick person coughs or talks, virus particles can spray from their mouth or nose into another person’s face. You’re most likely to inhale these droplets through your mouth or nose, but they can also enter through your eyes.
- You can also become infected by touching something that has the virus on it — like a table or doorknob — and then touching your eyes.
Find other ways you can help protect yourself and others on the Academy’s EyeSmart website.
About the American Academy of Ophthalmology
The American Academy of Ophthalmology is the world’s largest association of eye physicians and surgeons. A global community of 32,000 medical doctors, we protect sight and empower lives by setting the standards for ophthalmic education and advocating for our patients and the public. We innovate to advance our profession and to ensure the delivery of the highest-quality eye care. Our EyeSmart® program provides the public with the most trusted information about eye health. For more information, visit aao.org.
Ophthalmology, the official journal of the American Academy of Ophthalmology, publishes original, peer-reviewed, clinically-applicable research. Topics include the results of clinical trials, new diagnostic and surgical techniques, treatment methods, technology assessments, translational science reviews and editorials. For more information, visit www.aaojournal.org.