Windows of Infection: MRI Reveals COVID-19-Linked Eye Abnormalities

They might be dubbed the “windows to the soul,” but the COVID-19 pandemic has reinforced that the eyes are also “portals of infection.” Using MRI, radiologists are seeing significant optical abnormalities in patients who have suffered severe viral disease.

Unusual eye findings have been reported in patients infected with COVID-19 from the early stages of the pandemic – even before China declared its initial emergency. But, because providers are largely focused on more life-threatening aspects of the disease, these problems are frequently overlooked.

Even though the virus is known to mainly attack the lungs, impacts on the eye have been detected, including conjunctivitis, chemosis, optic neuritis, and retinopathy. But, to date, there has been little published research about what the virus can actually do to the eyes. In a study published Feb. 16 in Radiology, investigators from the French Society of Neuroradiology (SFNR) have presented the first ocular MRI findings associated with COVID-19.

56-year-old man presenting with severe COVID-19. Diagnosis of SARS-CoV-2 infection was based on a positive quantitative real-time RT-PCR test for SARS-CoV-2 nucleic acid performed on nasopharyngeal and lower respiratory tract swabs. The patient had been hospitalized in intensive care unit for 20 days when an MRI was performed due to delayed awakening despite discontinuation of sedation. He presented with acute respiratory distress syndrome, with a median Simplified Acute Physiology Score (SAPS II) of 45. He was intubated on high-flow supplementary oxygen and placed in the prone position. A, B, 3D FLAIR-weighted MRI reformatted in the axial plane showing several hyperintense nodules of the posterior pole of the globe located in the macular region (white arrowhead) and the extramacular region (black arrowheads). Note the presence of a focal temporal retinal detachment of the left eye (arrow).

Courtesy: RSNA

To learn more about what the virus does, the team enrolled 129 patients from 11 university and five general hospitals from March 4, 2020, and May 1, 2020. Six patients were obese, and two patients each had diabetes and hypertension. All patients had severe viral infection, and the team conducted 1.5T of 3T brain MRI scans on every participant.

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“We showed that a few patients with severe COVID-19 from the French COVID-19 cohort had one or several nodules of the posterior pole of the globe,” said lead study author Augustin Lecler, M.D., Ph.D., associate professor at the University of Paris and neuroradiologist at the Foundation Adolphe de Rothschild Hospital in Paris.

Of the 129 patients – 43 women and 86 men – nine (7 percent) had abnormal MRI finding in the globe of the eye, the team said. All nine patients had nodules in the macular region, the area of the eye that is responsible for central vision. Eight patients had nodules in both eyes. Two had nodules outside the macular region.

In addition, one patient had multiple infarcts in the anterior cerebral artery territory; one had a frontal hematoma; one had multiple micro-hemorrhages of the splenium of the corpus callosum; and one had leptomeningeal enhancement without parenchymal abnormalities. No patients had optic nerve, optic chiasm, or optic tract abnormalities.

These findings do not shed light on the mechanism behind the nodule formation. However, Lecler said, his team has several hypotheses around the root cause. Virus-triggered inflammation could be the culprit. Previous literature has reported human coronaviruses can prompt retinitis, choroiditis, retinal detachment, or optic neuritis. Another cause could be inadequate drainage of the eye veins caused by lying prone in the ICU or being intubated for extended periods of time. Seven of the affected patients had had long-term ICU admissions.

Despite not having clarity about what causes these eye abnormalities to develop, Lecler said, these findings still point to the need to screen patients who have had severe COVID-19 to detect any potential nodules.

“Our study advocates for screening of all patients hospitalized in the ICU for severe COVID-19,” he said. “We believe those patients should receive specific eye-protective treatments.”

Screening efforts could include using high-resolution MRI to explore the eyes, as well as fundoscopy, and optical coherence tomography.

According to Claudia F.E. Kirsch M.D., division chief of neuroradiology and professor of neuroradiology and otolaryngology at Zucker Hofstra School of Medicine at Northwell, this study is significant because it brings attention to a COVID-19 complication that has been largely overlooked.

“It is critical to remember that eye problems can go unrecognized in the ICU, and clinicians need to be vigilant in first identifying if there is an orbital problem to protect the patient’s vision,” she said. “Awareness of a new finding, the dissemination of this information, and sharing with colleagues leads to others recognizing the problem, education, research, understanding, and improved outcomes.”

The study, she said, is a reminder to radiologists to pay attention to the orbits on MRI, particularly with COVID-19 patients in the ICU.

And, this research is ongoing, Lecler said. His team is performing follow-up clinical and MRI exams on all COVID-19 survivors to determine if they have any long-term clinical consequences, such as vision loss or visual field impairment. Additional MRI assessments, paired with more comprehensive ophthalmological tests, are also underway for a next set of patients with both severe and moderate infection from the second and third waves of the pandemic.

“We have launched a prospective study with dedicated high-resolution MR images for exploring the eye and orbit in patients with light-to-moderate COVID,” Lecler said. “Therefore, we will be able to known whether our findings were specific to severe COVID patient or not.”