Frequency of retinal changes in patients with COVID-19: an observational study

In order to enter cells, SARS-CoV-2 virus uses the angiotensin-converting enzyme 2 receptor that is also expressed in retina.

Aim. Determination of the frequency and nature of retinal changes, evaluation of visual functions in patients who have got over COVID-19.

Materials and methods. This observational research includes 31 patients aged from 28 to 79 that got over COVID-19 (with severity according to computed tomography (CT): 1–3) in the period from 15 to 40 days before the research. Standard ophthalmological examination and optical coherence tomography (OCT) were performed; visual acuity measurement and threshold static perimetry were used to assess visual functions.

Results. Pathology of the ocular surface wasn’t detected. Ophthalmoscopy revealed retinal changes in only one patient. At OCT, 27 (87%) patients proved to have de novo changes in the retinal neuroepithelium at the level of the internal plexiform layer and the retinal ganglion cell layer in the form of hyper-reflective polymorphic foci with clear borders; 18 (67%) patients had monocular lesions. The maximum corrected visual acuity didn’t differ from the previously defined one; no violations of retinal light sensitivity were detected. No association was found between the severity of CT lung changes and retinal changes. The detected retinal changes weren’t associated with symptoms of anosmia (hyposmia) and ageusia. OCT repeated after 12–15 days showed no dynamics of hyperreflective foci: they remained unchanged in their shape, echogenicity and size.

Conclusion. De novo changes in retinal neuroepithelium at the level of the inner plexiform layer and the retinal ganglion cell layer were detected according to OCT data in 87% of patients who had undergone COVID-19. Anatomical changes in the retina weren’t manifested by functional visual disturbances. There is no association of retinal changes with lesions of I and IX cranial nerve pairs.