Abstract
Purpose :
The pathogenesis of Post-COVID syndrome (PCS) is still elusive. Recent data suggest that a subgroup of patients with PCS suffer from an impaired capillary microcirculation, which seemed to be mapped on the retina by OCT-angiography (OCT-A). As a restriction of capillary flow results in a local ischemia, the present study aimed to investigate potential alterations of that retinal layer (i.e. inner nuclear layer, INL), which was observed to show the impaired capillary microcirculation in patients with PCS and controls.
Methods :
Two hundred and ninety-four eyes of 152 subjects were recruited at the Department of Ophthalmology, University of Erlangen-Nürnberg: 161 eyes of 83 patients with PCS (24 female, 59 male, mean age 39±13 years) and 133 eyes of 67 controls (29 female, 38 male, mean age 3±6 years). Thickness of INL was measured by Spectral Domain Spectralis II (Heidelberg Engineering, Germany) using ETDRS circles of 1 mm and 3 mm around the fovea in the superior, inferior, nasal and temporal sector. In order to provide a high transverse and axial resolution, a projection artefact removal (PAR) algorithm and TruTrack1 eye tracking were used. The scans were checked for artefacts or shadows prior to analysis. The study has been approved by the local ethics committee and performed in accordance to the tenets of the Declaration of Helsinki. Age and gender were included as covariates in the mixed models to address potential confounding.
Results :
LS Means of INL-thickness were 41.90±0.36 µm in PCS and 40.80±0.38 µm in controls, respectively. No age-dependent alterations of INL-thickness were observed within all subjects (p≥0.16). Mixed model analysis showed a significant increased thickness of LS-mean of INL in PCS compared to controls (p=0.038). Regional analysis yielded an increased thickness of INL, especially in the temporal (p=0.039) and inferior (p=0.015) macular regions.
Conclusions :
As the ACE-2 protein, being the target of SARS-CoV-2, is present in the retinal inner granular and nuclear layers, the present data might show a morphometric result of consequences of viral affection of retinal structures with consecutive impaired retinal capillary flow and thus, reactive ischemic (i.e. thickened) surrounding.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.