COVID-19, caused by the SARS-CoV-2 virus, is primarily known for its respiratory symptoms, but the infection can also involve other organ systems, including the eyes. Ocular manifestations are a recognized part of the disease spectrum, affecting vision and eye health. These effects range from relatively mild, surface-level irritation during the acute phase to rare, more serious complications involving the deeper structures of the eye. Understanding these potential symptoms and mechanisms is important for managing overall health during and after infection.
Common Ocular Symptoms During Acute Infection
The most frequently reported eye-related issue during an active COVID-19 infection is viral conjunctivitis, commonly known as pink eye. This condition involves the inflammation of the conjunctiva, the thin membrane covering the white part of the eye and the inner surface of the eyelids. Symptoms typically include redness, a gritty feeling, and mucoid discharge.
Many patients also report a foreign body sensation, or the feeling that something is stuck in the eye, alongside excessive tearing (epiphora). These surface symptoms often appear concurrently with the more familiar respiratory or systemic signs of COVID-19.
Other common complaints include ocular pain, burning, and sensitivity to light (photophobia). The prevalence of ocular symptoms varies widely, but some studies estimate it affects up to one-third of COVID-19 patients. For most people, these mild surface irritations are self-limiting and resolve naturally as the main viral illness clears.
Mechanisms of Viral Entry and Ocular Inflammation
The SARS-CoV-2 virus can directly affect the eyes because specific protein receptors are present on the ocular surface. The virus uses the Angiotensin-Converting Enzyme 2 (ACE2) receptor as its primary entry point into human cells. This receptor, along with the co-receptor TMPRSS2, is found in ocular surface cells, including the conjunctiva and the cornea.
This biological setup creates two primary pathways for the eye to be affected during infection. One pathway involves the direct infection of the eye’s outer layer, leading to the localized inflammation seen in conjunctivitis. The virus can also reach the eyes through the nasolacrimal duct, which connects the nasal cavity to the corner of the eye, allowing travel from the upper respiratory tract.
The second, more systemic pathway involves the generalized inflammatory response triggered by the infection. The body’s immune reaction, sometimes referred to as a cytokine storm, can damage the delicate vascular system throughout the body, including blood vessels within the eye. This widespread inflammation and the associated risk of blood clotting can lead to more serious complications affecting the deeper structures of the eye.
Severe and Long-Term Vision Complications
While less common than surface irritation, some COVID-19 complications involve the deeper, internal structures of the eye and can pose a threat to vision. One issue is retinal vascular occlusion, which occurs when a blood clot blocks an artery or vein within the retina. A blockage in the retinal artery, sometimes called an eye stroke, can cause sudden, painless vision loss due to a lack of oxygenated blood reaching the tissue.
Another infrequent complication is optic neuritis, which is the inflammation of the optic nerve that transmits visual information from the eye to the brain. This condition can lead to temporary or permanent vision changes, including blurred vision, reduced color vision, or pain with eye movement. These severe events are typically linked to the systemic effects of the virus, such as hypercoagulability or autoimmune responses.
Beyond the acute phase, chronic dry eye syndrome is frequently reported as a persistent, long-haul symptom. This condition involves discomfort, fluctuating vision, and persistent irritation long after the initial infection has cleared. Ongoing research also suggests a link between the infection and corneal nerve damage, which may contribute to lasting dry eye symptoms.
Management and Eye Protection
For common, mild symptoms like conjunctivitis and irritation, management focuses on symptomatic relief and preventing viral spread. Applying a cool compress several times a day can help reduce swelling and discomfort. Artificial tears or lubricating eye drops are often recommended to alleviate dryness and the foreign body sensation.
It is important to avoid rubbing the eyes, even when irritated, as this can worsen inflammation and potentially transfer the virus from the hands to the ocular surface. Frequent hand washing remains a highly effective protective measure against viral transmission to the eyes. Contact lens wearers may consider temporarily switching to glasses to reduce the frequency of touching their eyes.
Immediate consultation with an eye care professional is advised if a patient experiences sudden vision loss, severe and unremitting eye pain, or new onset of blurry vision. In high-exposure settings, such as healthcare environments, wearing wraparound safety glasses, goggles, or a full face shield provides the best protection. Regular prescription glasses do not completely shield the eyes from airborne respiratory droplets.