The SARS-CoV-2 virus can enter the body through the eyes, which is a valid concern because they are an exposed part of the face. Scientific evidence confirms the ocular surface is a potential entry point for the virus that causes COVID-19. The eye’s conjunctiva, the clear membrane covering the white of the eye and the inside of the eyelids, is a mucosal surface similar to the lining of the mouth and nose. This surface allows viral particles to gain access to the body.
How SARS-CoV-2 Reaches the Eye
SARS-CoV-2 enters the eyes through two main pathways that allow contact with susceptible ocular tissue. The first is direct contact, occurring when respiratory droplets or aerosolized particles expelled by an infected person land directly onto the eye’s mucosal surface. A cough, sneeze, or close-range conversation can generate these virus-laden particles, which deposit on the conjunctiva.
The second, and often more common, mechanism is indirect transfer via contaminated hands. A person may touch a surface with viral particles and then unconsciously touch or rub their eyes. This hand-to-eye contact transfers the virus directly onto the conjunctiva or cornea, bypassing the eye’s natural tear film defenses.
The eye is susceptible because its cells possess the necessary machinery for the virus to initiate an infection. Surface cells of the conjunctiva and cornea express the Angiotensin-Converting Enzyme 2 (ACE2) receptor. SARS-CoV-2 uses its spike protein to latch onto this ACE2 receptor, which acts like a cellular doorknob. A co-factor enzyme called TMPRSS2, also present on the ocular surface, helps activate the viral spike protein and facilitates entry into the eye cells. Although the concentration of these receptors is lower than in the respiratory tract, their presence confirms the biological possibility of an ocular infection.
Ocular Manifestations of COVID-19
When SARS-CoV-2 infects the ocular surface, the most common clinical sign is viral conjunctivitis, often known as pink eye. This eye inflammation is a direct manifestation of the body’s immune response to the virus on the conjunctiva. Studies indicate that about 11% of COVID-19 patients experience at least one ocular symptom, with conjunctivitis accounting for the majority of those cases.
Symptoms of COVID-19-related conjunctivitis are similar to other viral forms. They include eye redness, irritation, a foreign body sensation, tearing, and itching. Increased sensitivity to light (photophobia) is also frequently reported. These ocular symptoms may be mild and develop alongside or after the typical respiratory signs of COVID-19.
In a small percentage of cases, conjunctivitis has been documented as the initial or sole presenting symptom of COVID-19 infection. The virus’s presence is confirmed by detecting SARS-CoV-2 viral RNA in the tear fluid and conjunctival swabs of infected patients. This suggests the eye acts as a potential reservoir, meaning tears and ocular secretions could transmit the virus to others.
Protecting the Eyes from Viral Entry
Simple, actionable steps can significantly reduce the risk of ocular transmission, given the eye’s role as a potential entry point for SARS-CoV-2. Strict hand hygiene is the most effective method, as indirect hand-to-eye contact is a primary transmission route. This involves thoroughly washing hands with soap and water for at least 20 seconds, especially after being in public spaces.
Reducing the frequency of touching the face, particularly the area around the eyes, is an important preventive measure. This requires conscious effort, as people often unconsciously rub their eyes throughout the day. For individuals who wear contact lenses, temporarily switching to glasses is a beneficial precaution. Handling contact lenses requires repeated hand-to-eye contact, increasing the opportunity for viral transfer.
Wearing protective eyewear provides a physical barrier against direct droplet exposure. Regular eyeglasses or sunglasses offer some protection by deflecting airborne particles and discouraging face touching. In higher-risk environments, such as healthcare settings or places with poor ventilation, specialized eye protection like goggles or face shields is necessary. These devices fully cover the eyes and surrounding areas, preventing both direct droplet deposition and aerosol exposure.