By now, most Americans are aware of the primary symptoms of SARS-CoV-2 infection: dry cough, shortness of breath, and fever. Ophthalmologists are likely aware of the many documented cases that involve conjunctivitis or characteristic lesions at the ganglion cell and inner plexiform layers. Now, researchers are pointing to a handful of COVID-19 associations with neuro-ophthalmic conditions, such as optic neuritis, visual disturbances and visual loss, cranial neuropathies, and Miller Fisher syndrome, a study published in Current Opinions in Ophthalmology shows.
“It is likely that an abnormal immune response contributes to the neurologic dysfunction observed in infected patients,” according to the researchers. “Patients who are COVID-19 positive may display increased levels of proinflammatory cytokines in the plasma which may be involved in the damage caused by the virus.”
Research shows that the main functional receptor for SARS-CoV-2 is ACE2, which is present on multiple organs, including the brain. It is therefore possible that the virus acts directly on neuronal tissue, the study speculates. It may even enter the brain by infecting choroid plexus or meninges.
The investigators pointed to a 26-year-old male SARS-CoV-2 patient who experienced severe bilateral optic neuritis and myelitis. He had previously experienced bilateral pain with eye movements, dry cough, numbness on the soles of his feet, and neck discomfort with forward flexion. On exam, he was found to have significant vision loss in both eyes, disc edema in both eyes, and retinal hemorrhages in the right. His left eye was 20/250. After 3 weeks of treatments with intravenous methylprednisolone, followed by
an oral prednisone taper, his vision dramatically improved.
The report notes a number of COVID-19 cases with Miller Fisher syndrome diagnoses or 6th nerve palsies, which may represent more limited forms of the Miller Fisher syndrome. One such patient, a 71-year-old hypertensive female in New York City, complained of diplopia and an inability to abduct her right eye. Magnetic resonance imaging (MRI) showed enhancement of her optic nerve sheaths and posterior Tenon capsules.
Two cases of severe bilateral vision loss were also noted — both with a history of stroke. One of those patients was a 34-year-old female with systemic lupus erythematosus, hypertension, end stage renal disease on hemodialysis, chronic obstructive pulmonary disease, and prior stroke. The other, 61-year-old COVID-19-positive male with diabetes was diagnosed with acute bilateral occipital territorial ischemic infarct. He exhibited only light perception in both eyes.
Other neurological conditions have been associated with COVID-19, as well. A retrospective case series conducted in Wuhan, China, examined the records of 214 patients infected with the virus, 36.4% displayed a broad range of nervous system signs and symptoms including headache, dizziness, hypogeusia, hyposmia, muscle damage, and ischemic and hemorrhagic stroke. A high percentage — in one study, 73% — of COVID-19 patients also experience anosmia and ageusia. At least 8 cases of Guillain–Barre syndrome development in the context of COVID-19 infection have also been noted.
“During this pandemic, COVID-19 should be kept on the differential for any patient presenting with new bilateral vision loss or [cerebrovascular accident],” the researchers suggested. They added that ophthalmologists should recommend COVID-19 testing for any patient who presents with diplopia, pain with eye movements, changes in visual acuity, changes in color vision, or difficulty ambulating.
Tisdale A, Chwalisz B. Neuro-ophthalmic manifestations of coronavirus disease 19. Curr Opin Ophthalmol. 2020;31(10):489-494. doi: 10.1097/ICU.0000000000000707.