The symptoms associated with COVID-19 are varied, extending beyond the commonly known respiratory issues like cough and difficulty breathing. Clinical observations raised questions about whether the virus could manifest with non-respiratory signs, particularly those affecting the eyes. Watery eyes, medically termed epiphora or excessive lacrimation, became a frequently reported concern. This symptom involves the overproduction or impaired drainage of tears. Understanding its link to the SARS-CoV-2 virus is important for patients and healthcare providers.
Ocular Symptoms and COVID-19 Infection
COVID-19 can directly cause watery eyes, often observed within the context of viral conjunctivitis, or “pink eye.” This ocular involvement means the virus is affecting the eye’s surface, specifically the conjunctiva, the thin membrane covering the white part of the eye and the inner surface of the eyelids. While respiratory symptoms are more common, studies show that a significant minority of patients experience some form of ocular symptom. Tearing (epiphora) is one of the more frequent eye complaints reported in COVID-19 patients.
Other related eye symptoms often accompany the excessive tearing, including eye redness, irritation, a gritty sensation, and sometimes a mild watery discharge. The prevalence of any ocular manifestation varies across different studies, ranging from approximately 11% to over 30%. In rare instances, conjunctivitis and its associated watery eyes can be the sole presenting symptom of a SARS-CoV-2 infection, occurring before any respiratory or systemic signs develop.
The Biological Mechanism of Excessive Tearing
The excessive tearing is rooted in the virus’s ability to interact with the ocular surface. SARS-CoV-2 primarily gains entry into human cells by binding to the Angiotensin-Converting Enzyme 2 (ACE2) receptor. Research confirms that this ACE2 receptor, along with the facilitating enzyme TMPRSS2, is expressed on the cells of the human conjunctiva and cornea.
When the virus infects the conjunctival tissue, it triggers a localized inflammatory response. This infection and subsequent inflammation, known as conjunctivitis, irritates the ocular surface. The irritation stimulates the lacrimal glands to produce an abnormal amount of tears, attempting to flush out the irritant.
Differentiating COVID-Related Watery Eyes from Allergies and Colds
Distinguishing COVID-19-related watery eyes from those caused by seasonal allergies or the common cold relies on identifying key accompanying symptoms. Watery eyes from allergies are typically characterized by intense, uncomfortable itching of the eyes and often the nose or throat, a symptom less prominent in COVID-19 conjunctivitis. Allergic symptoms tend to be chronic or seasonal, often recurring yearly and responding well to antihistamines.
In contrast, COVID-19 watery eyes are frequently accompanied by significant systemic symptoms that allergies do not cause, such as fever, profound fatigue, body aches, or the sudden loss of taste or smell. The common cold can also cause transient tearing alongside typical upper respiratory congestion, but it usually lacks the systemic severity often associated with COVID-19. If watery eyes present alongside symptoms like a new, continuous cough or shortness of breath, a viral cause like COVID-19 is more likely than a simple allergy.
Symptom Management and When to Seek Medical Attention
For the management of mild watery eyes related to a viral infection like COVID-19, the focus is on comfort and preventing spread. Using preservative-free artificial tears can help soothe irritation and flush the ocular surface. Applying a cool compress over the eyelids can help reduce inflammation and make the eyes feel more comfortable. Patients who wear contact lenses should temporarily switch to glasses to reduce further irritation and the risk of complications.
Practicing meticulous hygiene is important, including frequent hand washing and avoiding touching or rubbing the eyes, to prevent the virus from spreading. While most COVID-19 eye symptoms resolve within a couple of weeks, certain warning signs require immediate consultation with a healthcare provider or eye specialist. These red flags include severe eye pain, any sudden change in vision, extreme sensitivity to light, or the presence of thick, purulent discharge. Seeking professional help is necessary if symptoms worsen or fail to improve after two to three days.