A study based in Brazil used OCT to evaluate patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the COVID-19 disease, and documented retinal findings possibly associated with COVID-19 infection in humans. According to The Lancet, the researchers believe their ganglion cell and plexiform layer findings could be associated with central nervous system manifestations that have been described previously in animal studies and in COVID-19 neurological events.

The study assessed retinal and OCT changes in 12 adults (six men and six women between the ages of 25 and 69), examined between 11 and 33 days after COVID-19 symptom onset. Nine patients tested positive for SARS-CoV-2 by nasal and oral swab tests, and two patients tested positive for antibody tests.

All patients showed hyper-reflective lesions at the level of ganglion cell and inner plexiform layers, more prominently at the papillo-macular bundle in both eyes. The researchers noted that OCT-angiography and ganglion cell complex analysis results appeared normal.

With fundus examination, color fundus photography and red-free imaging, they found subtle cotton-wool spots and microhemorrhages along the retinal arcade in four patients. Visual acuity and pupillary reflexes were normal in all eyes, and the study detected no symptoms or signs of intraocular inflammation.