The SARS-CoV-2 virus, responsible for the COVID-19 pandemic, primarily affects the respiratory system, but the infection is systemic and can involve various organs, including the eyes. Ocular involvement can occur through the body’s generalized inflammatory response or direct viral action. Recognizing the range of eye-related symptoms and risks associated with COVID-19 is important for understanding the disease. These effects range from mild surface irritation during the acute phase to rare, potentially vision-threatening complications that can emerge later.
How the Virus Enters the Eye
The eye serves as a potential gateway for SARS-CoV-2, acting as a mucosal surface similar to the nose and mouth. Entry is facilitated by the presence of the angiotensin-converting enzyme 2 (ACE2) receptor, the primary protein the virus uses to bind to and infect human cells. ACE2 receptors are expressed on the surface of the human eye, specifically on the epithelium of the conjunctiva and the cornea.
The conjunctiva, which covers the front of the eye and inner eyelids, is particularly susceptible to infection due to this receptor expression. A second protein, TMPRSS2, which helps activate the viral spike protein, is also present on the ocular surface, supporting the eye’s potential as a site for viral entry and replication. Transmission occurs when infectious respiratory droplets land directly on the eye, or indirectly through contaminated hands. The virus can be detected in tear fluid, raising concerns about eye secretions potentially transmitting the virus to others.
Common Acute Ocular Symptoms
The most frequent eye manifestation during the active phase of COVID-19 is viral conjunctivitis, commonly known as “pink eye.” This condition involves inflammation of the conjunctiva, with symptoms that are generally mild and temporary, typically resolving within a few days to two weeks. Common complaints include eye redness, increased tearing, and a gritty or foreign body sensation.
Patients often report eye soreness, burning, and itching. Light sensitivity, or photophobia, is also a reported symptom during the acute illness. Management focuses on comfort and relief, such as using cool compresses to reduce swelling and redness.
Artificial tears or lubricating eye drops can help alleviate dryness and grittiness. Individuals should temporarily avoid wearing contact lenses to prevent further irritation. While most cases resolve without specific treatment, persistent or worsening symptoms warrant consultation with an eye care professional.
Rare and Severe Ocular Complications
Beyond common surface irritation, COVID-19 can lead to less frequent but serious complications affecting the internal structures of the eye. These severe events often result from the systemic effects of the infection, particularly the body’s inflammatory response and hypercoagulability (excessive blood clotting). One set of complications involves retinal vascular events, which are essentially “eye strokes.”
These include retinal artery occlusion (RAO) and retinal vein occlusion (RVO), where a blood clot blocks blood flow to or from the retina. An artery blockage can lead to sudden, painless vision loss, while a vein blockage can cause bleeding, swelling, and gradual or sudden blurry vision. Blockages may also result in “cotton wool spots,” areas of the retina where tissue dies due to lack of oxygen.
Other severe complications involve the nervous system and internal eye inflammation. Optic neuritis is inflammation of the optic nerve, potentially causing pain and temporary or permanent vision loss. Uveitis, inflammation of the middle layer of the eye, can cause blurry vision, floaters, and increased light sensitivity. Immediate medical attention is necessary if a person experiences sudden changes in vision during or shortly after a COVID-19 infection.
Post-Infection and Long-Term Visual Changes
Visual symptoms may persist or emerge long after the acute COVID-19 infection has cleared, becoming part of the post-COVID-19 condition, often called “Long COVID.” These lingering issues are distinct from initial acute symptoms and can affect daily life for months. A common long-term complaint is chronic dry eye syndrome, which causes persistent discomfort, a sandy or gritty sensation, and fluctuating blurred vision.
This dryness is sometimes linked to surface abnormalities and changes in tear composition. Chronic light sensitivity (photophobia) is another reported symptom that can linger post-recovery, making it difficult to tolerate bright environments or screen time. Some individuals also report persistent blurred vision, floaters, or difficulty focusing, which may be related to subtle, ongoing inflammation or changes in the eye’s internal structures.
The exact mechanisms behind these long-term visual changes are not fully understood. Hypotheses involve ongoing, low-grade systemic inflammation, immune dysregulation, or residual neurological effects. Cases of post-COVID optic neuritis and retinal vascular issues have been documented weeks or months after the initial illness. These ongoing symptoms emphasize the need for continued monitoring and specialized care for those with persistent visual complaints following their recovery from the virus.