Since the start of the COVID-19 pandemic in late 2019, there have been more than 6.5 million confirmed cases of the disease worldwide. COVID-19 is caused by a newly discovered virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Viruses in the coronavirus family cause various kinds of respiratory infections, including the common cold, Middle East respiratory syndrome (MERS), and severe acute respiratory syndrome (SARS).

The virus that causes COVID-19 is highly contagious and can result in either mild or severe illness. According to the World Health Organization (WHO), the symptoms include:

Although less common, COVID-19 may also lead to the development of pink eye in about 1 to 3 percent of people.

In this article, we’re going to take a look at why COVID-19 may cause pink eye, and what other eye symptoms people with COVID-19 may experience.

It’s thought that up to 3 percent of people with COVID-19 develop ophthalmological symptoms (symptoms affecting the eyes).

In comparison, the Centers for Disease Control and Prevention (CDC) estimates that 83 to 99 percent of people develop a fever and 59 to 82 percent of people experience a cough.

A study published in the British Journal of Ophthalmology that looked at one person with COVID-19 found that eye symptoms occurred in the middle stages of infection.

Additional research involving more participants is needed to verify that this is typical, however.

Pink eye

Pink eye, also known as conjunctivitis, is an inflammation of the clear tissue over the whites of your eyes and the inside of your eyelids. It usually leads to redness and swelling of your eyes. A viral or bacterial infection can cause it.

A review of three studies published in late April 2020 examined how common pink eye is among people with COVID-19.

The researchers examined a total of 1,167 people with either mild or severe COVID-19.

They found that 1.1 percent of people developed pink eye, and that it was more common in people with severe COVID-19 symptoms.

Only 0.7 percent of people with mild symptoms developed pink eye, while it occurred in 3 percent of people with severe symptoms.

A study published in late February 2020 examined the COVID-19 symptoms of 1,099 people with the disease in 552 hospitals in China. Researchers found that 0.8 percent of the people with COVID-19 had symptoms of pink eye.

Chemosis

One study published in JAMA Ophthalmology examined the symptoms of 38 people who were hospitalized for COVID-19. Twelve of the participants had symptoms related to the eye.

Eight of these people experienced chemosis, which is a swelling of the clear membrane that covers the whites of your eyes and inner eyelid. Chemosis can be a symptom of pink eye or a general sign of eye irritation.

Epiphora

In the same study, researchers found that seven people had epiphora (excessive tearing). One of the participants experienced epiphora as their first symptom of COVID-19.

Increased eye secretion

Seven of the participants in the JAMA Ophthalmology study experienced increased eye secretions. (Your eyes normally produce an oily film to help keep them lubricated.)

None of the participants experienced an increase in eye secretions at the beginning of their illness.

The new coronavirus that causes COVID-19 primarily travels through droplets in the air when someone with an infection sneezes, speaks, or coughs. When you breathe in these droplets, the virus enters your body and can replicate.

You can also contract the virus if you touch surfaces that the droplets may have landed on, such as tables or handrails, and then touch your eyes, nose, or mouth. However, this is not thought to be the main way that the virus spreads

It’s suspected that the virus can also be transmitted through the eyes.

The virus responsible for the 2003 SARS outbreak is genetically similar to the coronavirus that causes COVID-19. Research on this outbreak found that a lack of eye protection put healthcare workers in Toronto at risk for contracting the virus.

The same research suggests that the risk of transmission through your eyes is relatively low compared to other means. However, taking precautions to protect your eyes is likely still a good idea.

Scientific knowledge of COVID-19 is rapidly evolving. It’s possible that future studies will find the risk is higher than originally thought.

How the virus gets into your eyes

The virus that led to the 2003 SARS outbreak entered the body through an enzyme called angiotensin converting enzyme 2 (ACE2). Research has also found that the virus that causes COVID-19 also likely does the same.

ACE2 is widely found in places throughout your body, including your heart, kidney, intestines, and lungs. ACE2 has also been detected in the human retina and the thin tissue that lines your eye.

The virus enters human cells by tricking cells into thinking that it’s ACE2.

The virus can attach to a cell at a particular spot, called a receptor, where ACE2 fits exactly. The virus mimics the shape of the ACE2 enzyme well enough that the cell allows the virus to enter it, same as it would the enzyme.

Once in the cell, the virus is protected and can replicate until it ruptures the cell. Copies of the virus find new cells to invade, repeating the process.

When the virus reaches your eyes, it may cause pink eye or other eye symptoms.

Protecting your eyes from airborne respiratory droplets may help reduce your chances of contracting the new coronavirus.

Here’s how to protect your eyes:

  • Avoid rubbing your eyes, especially in public and with unwashed hands.
  • Switch from contact lenses to glasses. While there’s no evidence that glasses or sunglasses decrease your risk for infection, some people wearing contacts may rub their eyes more.
  • Follow other recommended practices. Wash your hands frequently, limit touching your face, avoid contact with sick people, follow physical distancing best practices, and wear a mask in public.

Having pink eye or irritated eyes doesn’t mean you have COVID-19.

There are many other reasons your eyes might be red or swollen, including:

Eye-related symptoms are rare for people at the beginning of COVID-19.

So far, there haven’t been any reports of sight-threatening symptoms of COVID-19, so it’s most likely that your eye symptoms will be mild.

Your doctor may be able to recommend specific ways to manage your symptoms, such as eye drops.

To reduce the transmission of COVID-19, get in touch with your doctor by phone or video appointment instead of going to a clinic. If you have COVID-19, you may transmit the virus to others at a clinic or hospital.

To reduce the risk of transmitting the virus to other people, including healthcare workers, avoid going to a hospital if your symptoms are mild. About 80 percent of people with COVID-19 have mild symptoms.

Many clinics are offering virtual visits, which involve talking to a doctor either by phone or online. These services lower your chances of transmitting the virus to others. They’re a better option than visiting a doctor’s office if your symptoms are mild.

Medical emergency

If you or a loved one has any of the following emergency COVID-19 symptoms, get in contact with a medical professional right away:

  • trouble breathing
  • chest pain
  • blue lips or face
  • confusion
  • inability to wake

Some people with COVID-19 develop pink eye, but it’s not as common as other symptoms like fever, dry cough, and fatigue. Research has also found it seems to be a more common symptom in people with severe cases of COVID-19.

Minimizing contact with your eyes and taking other precautions, like wearing a face mask in public, washing your hands frequently, and practicing physical distancing, can help reduce your chances of contracting the new coronavirus as well as developing pink eye.