Corneal Confocal Microscopy Identifies Corneal Nerve Fiber Loss in Patients with Long COVID

Article: Something in Patients' Eyes Could Reveal The Presence of 'Long COVID'
Source: ScienceAlert
Published: July 26, 2021
Article: ...researchers use pioneering eye exam to identify nerve damage in long COVID patients
Source: Weill Cornell Medicine-Qatar (Qatar)
Published: August 9, 2021

CCM images in a healthy patient (A), a patient with long COVID (B), and a patient with COVID-19 (C)

Long COVID is defined as "signs and symptoms that develop during or following an infection consistent with COVID-19 and which continue for more than 4 weeks and are not explained by an alternative diagnosis," according to the National Institute for Health and Care Excellence (NICE) in England. Long COVID affects at least 10% of individuals who have recovered from acute SARS-CoV-2 infection, with symptoms ranging from headaches and "brain fog" to numbness and neuropathic pain. The presence of neurologic symptoms prompted researchers to investigate whether an imaging technique called corneal confocal microscopy (CCM) can be used to identify underlying nerve damage in patients with long COVID. A quick and non-invasive technique for real-time imaging of corneal nerve fibers, corneal confocal microscopy is useful in identifying tell-tale signs of corneal nerve damage in neurodegenerative diseases such as diabetic neuropathy and multiple sclerosis, and now long COVID, as indicators of nerve damage elsewhere in the body. The present study examined 40 patients who had recovered from COVID-19 three to four months previously, and compared them with 30 healthy control participants who never had the disease. They found evidence of both nerve damage and increased dendritic cells (a type of immune cell) in the corneas of individuals with long COVID, with the severity of nerve damage correlated with the severity of disease at presentation. Based on their findings, the authors argue that CCM has the potential to be a valuable diagnostic tool to diagnose and assess cases of long COVID. One of the researchers adds, "The identification of underlying nerve damage also allows us to think about this condition as a neurodegenerative disease, which may be amenable to treatment.”

My rating of this study: ⭐⭐

Bitirgen G, Korkmaz C, Zamani A, et al. "Corneal confocal microscopy identifies corneal nerve fibre loss and increased dendritic cells in patients with long COVID." British Journal of Ophthalmology.  26 July 2021. https://doi.org/10.1136/bjophthalmol-2021-319450