Conjunctivitis, commonly known as pink eye, is an inflammation of the clear membrane covering the white part of the eye and the inner surface of the eyelid. Pink eye is a reported symptom of COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While it is not the most frequent symptom, pink eye can indicate a COVID-19 infection and may sometimes be the first or only symptom a person experiences. This connection highlights the eye as a potential route for viral entry and transmission.
How SARS-CoV-2 Affects the Eyes
The link between the SARS-CoV-2 virus and conjunctivitis is rooted in the presence of specific receptors on the eye’s surface. The virus primarily gains entry into human cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. Research confirms that ACE2 receptors are expressed on the human conjunctiva and cornea, suggesting that the ocular surface is susceptible to infection. Once the virus accesses these cells, it triggers an inflammatory response in the conjunctiva, resulting in the symptoms of pink eye.
Conjunctivitis related to COVID-19 is considered a less common manifestation, affecting approximately 1% to 11% of those infected. When it occurs, the eye symptoms are often mild and typically present alongside characteristic respiratory symptoms like fever, cough, and fatigue. Ocular symptoms usually involve red, inflamed eyes, a watery discharge, and a gritty or sandy sensation, sometimes accompanied by light sensitivity. The viral genetic material of SARS-CoV-2 has been detected in the tears of infected patients, confirming the eye as a source of the virus.
Identifying the Cause of Conjunctivitis
Determining the cause of pink eye is important because treatment varies among the different types. Viral conjunctivitis, including the type caused by SARS-CoV-2, is characterized by a thin, watery discharge and often affects one eye before spreading to the other. This form is frequently associated with symptoms of a common cold or other respiratory infection. Viral cases usually resolve on their own within one to two weeks.
Bacterial conjunctivitis presents differently, usually involving a thick, pus-like discharge that is yellow or greenish in color. This discharge can cause the eyelids to stick together, especially upon waking, and the condition often requires antibiotic eye drops for effective treatment. Unlike the systemic symptoms of a viral infection, bacterial pink eye is less likely to be accompanied by a fever or upper respiratory illness.
A third major category is allergic conjunctivitis, which is not contagious and is triggered by environmental factors like pollen or pet dander. The hallmark is intense itching, often accompanied by significant tearing and swelling in both eyes simultaneously. People with allergic conjunctivitis often experience other allergy symptoms, such as sneezing or a runny nose. Distinguishing between these types is important, as misdiagnosing a viral case as bacterial can lead to antibiotic overuse.
Treatment and Prevention Strategies
Treatment for conjunctivitis suspected to be related to COVID-19 focuses mainly on supportive care. Since it is a viral infection, antibiotic drops are ineffective unless a secondary bacterial infection is present. Relief can be found by applying cool compresses and using over-the-counter artificial tears to lubricate the eyes and reduce irritation. Stop wearing contact lenses immediately until symptoms have fully resolved.
Because the tears can contain the SARS-CoV-2 virus, strict personal hygiene is necessary to prevent transmission. Frequent handwashing and avoiding touching or rubbing the eyes are the primary preventative steps. Individuals with pink eye and other COVID-19 symptoms must follow local isolation guidelines to limit the spread of the illness. Seek immediate medical attention if symptoms include severe eye pain, changes in vision, or increased sensitivity to light, as these signs may indicate a more serious underlying issue.