Changes in nerve fibers in the eyes can help confirm a diagnosis of “long COVID” – debilitating symptoms that persist more than four week after recovery from the acute illness, according to new findings.
Because nerve fiber damage is suspected to underlie some of these lingering symptoms, ophthalmologists used a non-invasive technique called corneal confocal microscopy to check for nerve damage in the cornea.
In their study of 40 COVID-19 survivors – most of whom had not been sick enough to need extra oxygen – and 30 uninfected individuals, the researchers found “significant associations” between nerve fiber loss in the cornea and the presence and severity of long COVID symptoms related to nerves, muscles and bones.
The corneal changes were most evident in patients with persistent neurological symptoms, such as loss of taste and smell, headache, dizziness, numbness and nerve pain, according to a report published in the British Journal of Ophthalmology.
Corneas of patients with long COVID also contained more immune cells called dendritic cells, reflecting the body’s response to injury. “We believe corneal confocal microscopy … will allow clinicians to make the diagnosis of long COVID with greater confidence,” said coauthor Dr. Rayaz Malik of Weill Cornell Medicine Qatar.