Update: February 21, 2025: Non-Hospitalized Long COVID Patients Exhibit Reduced Retinal Capillary Perfusion
In patients with long COVID, researchers found that the most significant change was a decrease in blood flow in the smallest blood vessels in the deeper layers of the retina. Researchers believe this decrease in circulation may reflect reduced blood flow in the brain, potentially leading to neurological symptoms.
“In oculomics—the field of study that examines the relationship between eye health and systemic diseases—we are understanding the power of the retina as a biomarker for disease, identifying early signs of diabetes, cardiovascular disease, and neurodegenerative disorders. It’s exciting to see how long COVID could fit into this framework,” said Dr. Gill. “Retinal imaging allows us to see the blood vessels that we cannot readily image elsewhere, so in this context, the eyes really are the ‘window to the soul.'”
“This finding bridges gaps between ophthalmology, neurology, and COVID-19, helping us better understand how inflammation affects different organs in the body,” said Manjot K. Gill, MD, senior author of the study and ophthalmology lead of the Northwestern Medicine Comprehensive COVID-19 Center. “The change in blood vessels in the deep part of the retina supports the hypothesis that long COVID affects similar blood vessels in other parts of the body, like the brain, which can potentially contribute to the symptoms of long COVID such as memory loss, brain fog and fatigue.”
Original Article
“Dr Betty Raman, from the University of Oxford and one of the lead investigators on the study, says it is clear that those living with long-COVID symptoms are more likely to have experienced some organ damage.”
The biggest impact was seen on the lungs, where MRI scans were 14 times more likely to show abnormalities. Scans were also three times more likely to show abnormalities in the brain, and twice as likely in the kidneys, among people who had severe COVID.
The article Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study was published September 22, 2023 in The Lancet Respiratory Medicine.
After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.
ABOUT LONG-COVID
Long-standing multiorgan impairment following SARS-CoV-2 infection has been a major concern for individuals recovering from severe disease and is thought to be caused by a multitude of factors, including direct viral cytotoxicity, chronic inflammation, ischaemic injury, acute reactivation of other viruses, metabolic derangements, and acute treatment effects (especially invasive ventilation). Numerous reports of delayed organ complications such as myocarditis, stroke, and pulmonary emboli have led to speculations that the multiorgan dysfunction caused by COVID-19 might be responsible for impaired recovery and ongoing symptoms in individuals, a condition referred to as long COVID.