The answer to whether COVID-19 can cause pink eye is an unequivocal yes. Conjunctivitis, or pink eye, is an inflammation of the conjunctiva, the thin membrane covering the white part of the eye and the inner surface of the eyelids. The virus that causes COVID-19, SARS-CoV-2, can trigger this inflammation, resulting in symptoms like redness, swelling, and increased tearing. While it is a recognized manifestation of the infection, it is typically considered one of the less common symptoms when compared to classic respiratory issues.
The Direct Connection
Conjunctivitis is a confirmed, though relatively infrequent, symptom observed in people who have tested positive for COVID-19. Studies have shown a wide range of reported prevalence, with estimates varying from about 0.8% to 31.6% of COVID-19 cases. In adults, the rate is often cited as being on the lower end, around 1% to 3%, while some studies suggest a higher incidence in children. This eye irritation may appear early in the course of the illness, sometimes even preceding other systemic symptoms like fever or cough.
The eye symptoms can also develop later, even in patients who are hospitalized with a more severe infection. In some rare instances, conjunctivitis has been reported as the only noticeable sign of a SARS-CoV-2 infection. While it is not a common presentation, its presence alongside other symptoms warrants suspicion of COVID-19, particularly during periods of high community transmission. Recent variants have also shown a greater propensity to cause this symptom, with the XBB.1.16 “Arcturus” subvariant being specifically noted for its connection to pink eye, especially in younger populations.
How SARS-CoV-2 Affects the Eyes
The biological mechanism that allows SARS-CoV-2 to infect the eye and cause inflammation involves specific cellular receptors. The virus requires the Angiotensin-Converting Enzyme 2 (ACE2) receptor and the protease TMPRSS2 to gain entry into human cells. These receptors are present on the surface of various ocular tissues, specifically the epithelial cells of the conjunctiva and the cornea. The co-expression of ACE2 and TMPRSS2 in these cells makes the eye susceptible to viral binding and subsequent infection.
When aerosolized droplets from a cough or sneeze contact the eye’s surface, the virus can bind to the ACE2 receptors found there. This direct infection leads to inflammation of the conjunctiva, resulting in pink eye. Furthermore, the virus has been detected in the tear film of infected individuals, suggesting the eye can act as both a portal of entry and a potential source for viral shedding. The inflammation is a localized immune response to the viral replication occurring in the ocular surface cells.
Distinguishing Viral Conjunctivitis
COVID-related pink eye falls under the category of viral conjunctivitis, and its appearance is similar to that caused by other common viruses, such as adenoviruses. It is typically characterized by redness, watering, and a gritty or foreign body sensation in the eye. The discharge associated with a COVID-19 infection is usually clear and watery, distinguishing it from the thick, sometimes greenish or yellowish, discharge characteristic of bacterial conjunctivitis.
This type of viral infection often begins in one eye, described as unilateral, before potentially spreading to the other eye, making it bilateral. Unlike allergic conjunctivitis, which causes intense itching, viral pink eye symptoms are generally dominated by irritation, burning, and light sensitivity. Another differentiating sign is the presence of preauricular lymphadenopathy, which is a swelling of the lymph nodes in front of the ear. Recognizing these specific symptoms is crucial, as the watery nature points toward a viral cause requiring a different management approach than a bacterial infection.
Management and Eye Safety
Management for COVID-19-related conjunctivitis, like most viral pink eye, is primarily supportive and focused on relieving symptoms. Applying cool compresses to the eyes several times a day can help reduce inflammation and discomfort. Using artificial tears can also soothe the irritation, dryness, and gritty feeling. Individuals who wear contact lenses should temporarily switch to glasses until the symptoms have fully resolved to prevent further irritation or complications.
It is important to seek professional medical attention if symptoms include intense eye pain, significant sensitivity to light, or any noticeable change in vision. These signs could indicate a more serious ocular complication that requires prompt assessment. Strict hand hygiene is crucial for preventing the spread of the virus to others and to the uninfected eye. Frequent handwashing and avoiding touching the eyes, nose, or mouth are essential steps, along with following isolation guidelines if a COVID-19 infection is suspected or confirmed.