The virus that causes COVID-19, SARS-CoV-2, is primarily known for infecting the body through the mucous membranes lining the nose and mouth. These tissues are the most common points of entry. However, the virus targets more than just the respiratory tract, raising a question about other pathways. Can this virus also gain access to the body through the surface of the eye? The answer is yes, the eye surface offers a viable, albeit less frequent, route for infection.
The Biological Entry Point
The possibility of eye-based infection is rooted in the specific biological mechanism the virus uses to invade human cells. SARS-CoV-2 requires a protein called the Angiotensin-Converting Enzyme 2 (ACE2) receptor. The virus uses its spike protein to attach to this receptor, gaining entry. This receptor is found extensively in the respiratory tract, but it is also present on the eye’s delicate outer layer.
The tissue covering the white of the eye and the inner eyelid is called the conjunctiva, and it contains the necessary ACE2 receptors. This means the virus has a biological mechanism to directly infect cells on the eye’s surface. Furthermore, the eye has a direct connection to the upper respiratory system through the nasolacrimal duct, or tear duct. This duct drains tears, along with any viral particles they may contain, from the eye’s surface down into the nasal cavity, providing a direct route to the throat and lungs.
Transmission Routes to the Eye
There are two main ways the SARS-CoV-2 virus can physically travel to the eye and initiate an infection. The first is through the direct landing of respiratory droplets. When an infected person coughs, sneezes, or speaks loudly, they expel microscopic droplets and aerosols. These particles can contain the virus and are propelled through the air, potentially landing directly on the exposed conjunctiva of a nearby person.
This direct exposure bypasses the body’s natural defenses in the nose and mouth, placing the virus right at a vulnerable mucosal surface. The second pathway is indirect contact, often involving contaminated hands. The virus can survive on surfaces for varying lengths of time, turning everyday objects into fomites. A person may touch a contaminated surface, like a doorknob or counter, and then unconsciously touch their eyes.
Touching or rubbing the eyes with a contaminated hand effectively transfers the viral particles directly to the conjunctiva. Since the average person touches their face many times per hour, this behavioral route represents a risk for viral transmission.
Protecting Your Eyes
Preventing eye-based transmission relies on both behavioral modifications and physical barriers. Consciously avoiding touching or rubbing the eyes, nose, and mouth is a simple defense. This habit breaks the chain of indirect transmission from contaminated hands to the vulnerable mucosal surfaces.
Rigorous hand hygiene is the primary defense, as frequent and thorough washing removes viral particles before they can be transferred to the face. When in high-risk environments, such as crowded indoor spaces or when caring for a sick individual, protective eyewear can provide an added layer of defense. Safety glasses, goggles, or face shields create a physical barrier that blocks airborne respiratory droplets from landing directly on the eye surface.
For individuals who wear contact lenses, maintaining strict lens hygiene is important. Some eye care professionals suggest switching to glasses during periods of high community transmission. Wearing glasses naturally discourages a person from touching their eyes and provides a partial shield against incoming droplets. Combining these protective layers reduces the opportunity for the virus to use the eye as an entry point.