What is it about the eyes that have prompted the repeated coronavirus warnings?
Avoid touching your eyes, nose and mouth, the Centers for Disease Control and Prevention has warned again and again. Wear a face mask, which may be effective because they remind you not to touch your face and eyes, among other things. Or use face shields, if you are a health-care worker.
“If someone sneezes in your face or if you touch a contaminated surface and then rub your eye,” says Jessica Belser, a microbiologist at the CDC, you risk getting the novel coronavirus in your eyes.
You want to protect your eyes from respiratory viruses for two main reasons. There is a direct connection between the eyes and the nasal passages, which can lead to respiratory infection. And viruses can infect the eyes themselves, which is called conjunctivitis — or pinkeye.
Eyes have natural protective mechanisms such as tears to wash irritants away and immune mediators to combat threats that hang around. But viruses can take advantage of the eye in a couple of ways. They can bind to proteins in the eye, which are similar to those in the lining of the nose and throat. Then they can enter (infect) cells and replicate themselves. Viruses can also travel with tears through tiny holes in the eyelids and down a duct that drains into the nose.
“Sometimes people put eye drops in and find they can taste them,” says Laura Di Meglio, an optometrist at the Johns Hopkins Wilmer Eye Institute.
The story with covid-19, the disease caused by the coronavirus, is far from definitive. But observational studies suggest that eye protection reduces transmission, according to a review article published this month.
Scientists know much more about other viruses, such as those that cause flu and colds. Belser studies flu viruses and has demonstrated that exposure to the eyes can result in respiratory illness in an animal model. (This experiment used ferrets with customized goggles to deliver virus-containing aerosols.)
“Influenza can cause conjunctivitis and respiratory infection,” says Sonal Tuli, an ophthalmologist at the University of Florida. The same is true for adenovirus, a common cause of colds and bronchitis.
“At a day care or school, when you see an outbreak of conjunctivitis, you think adenovirus,” says Tuli, who also is a clinical spokesperson for the American Academy of Ophthalmology.
Conjunctivitis is an umbrella term for inflammation of the mucous membranes of the eye. It can be caused by viruses or bacteria, or allergens.
“Viral conjunctivitis is the most common and most contagious,” Di Meglio says. “It’s self-limiting, like the common cold.” That means it slowly goes away over time.
Bacterial conjunctivitis is less common and characterized by a lot of goop or crustiness around the eye, she says. In this case, see a doctor who can prescribe an antibiotic.
Antibiotics will not work on viruses. For viral pinkeye, the treatment is comfort care, Tuli says. Artificial tears can be soothing, as can cool compresses. Reducing eye irritation can also reduce the urge to rub your eyes.
Viral and bacterial conjunctivitis both are contagious. So don’t touch your eyes unless you’ve washed your hands, and don’t share towels or pillowcases.
There’s a day or two of infection before symptoms show, which is why most often both eyes are affected, Tuli says. It’s easy to cross-contaminate your eyes before you know you are infected.
If, in addition to being red and watery, your eyes are itchy then allergens likely are the culprit, Di Meglio says. Over-the-counter eye drops, including those that contain antihistamines, can help, as can oral allergy medications.
People who wear contacts are at more risk of any of these triggers because they’re putting something foreign in their eyes. Mind your hygiene, Di Meglio says, by washing your hands and disinfecting your lens case.
Many chemicals can irritate the eyes as well, such as cleaning solutions and hand sanitizer. “Alcohol” — the main ingredient in hand sanitizer — “can cause significant irritation and damage the surface of the eye,” Tuli says.
Certain autoimmune diseases, such as rheumatoid arthritis and lupus, can also cause eye redness.
How risky is it to see an eye doctor during the pandemic? Eye doctors are upping their safety procedures to keep patients, and themselves, safe. As other health-care providers are doing, they are minimizing time spent in the waiting room, screening patients and checking their temperatures, and requiring face masks.
“Everything we do is an extension of what we do normally,” says Ruth Williams, another clinical spokesperson for the American Academy of Ophthalmology. She wears an N95 mask and her regular glasses. Some of her colleagues wear goggles or face shields. Sometimes the doctor will tape a patient’s mask down to prevent fogging of equipment or to correct an ill-fitting mask.
“We have to weigh the risk of viral transmission to the ease of taking care of our patients,” Williams says.
Her practice, at the Wheaton Eye Clinic in Illinois, has been open since the second week of May without any covid-19 cases.
Williams says that people who are wary of being in such close quarters with an eye doctor can put off their eye exams or routine screenings for a while. Symptoms that should prompt a visit are decreased vision, pain, redness, flashes or floaters or double vision. These could be signs of something potentially serious.
“Protecting vision is such a high value thing,” she says.