Ocular repercussions in COVID-19 patients: structural changes of the retina and choroid.

BACKGROUND: Neurotropic capabilities of SARS-COVs allow viruses to reach the central nervous system by hematogenous neuronal dissemination. The human retina, as an extension of the Central Nervous System, may have some neurodegenerative and/or vascular modifications related to COVID-19.

OBJECTIVES: To evaluate choroidal and inner neural layers in participants previously recovered from COVID-19 compared to the control group using optical coherence tomography.

METHODS: With a cross-sectional approach, the sample ( n  = 96), constituted by patients who have recovered from COVID-19 ( n  = 56) and healthy participants control group ( n  = 40) were ophthalmologically characterized. The neurodegenerative and vascular histological assessment was performed using SD-OCT and the mean thickness was measured in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Retinal nerve fiber layer, Ganglion cell layer and subfoveal choroidal thickness were obtained through semi-automatic measurement.

RESULTS: A total of 40 controls (27 women [67.5%]) and 56 COVID-19 participants (34 women [60.8%]) were included in this first report. There were retinal thickness significant differences in nearly all inner ETDRS subfields: nasal 3 mm ( p  = .025), I3 ( p  = .049), and temporal 3 mm ( p  = .009). Also, a decrease in neural layers was found in the nasal 3 mm ( p  = .049) and temporal 3 mm ( p  = .029) during ganglion cell layer assessment. The peripapillary retinal nerve fiber layer thickness was thinner in the COVID-19 group in superior temporal ( p  = .019), nasal ( p  = .002), inferior temporal ( p  = .046) and global ( p  = .014). Concerning the subfoveal choroidal measurement, an increase was observed in the COVID-19 group ( p  = .002).

CONCLUSION: Participants who had recovered from COVID-19 showed a non-glaucomatous neuropathy trend pattern. We found differences closer to the classic description of the "bow-tie" observed in other neurological as compressive neuropathies at the chiasma location. OCT assessment also showed an increase in choroidal thickness as a result of vascular changes.