Assessment of early and long-COVID related retinal neurodegeneration with optical coherence tomography 2022 Dağ Şeker and Timur

[Andy]

Abstract

Purpose
The aim of this study is to investigate short-term and long-term effects of coronovirus 19 disease (COVID-19) at inner and outer retinal layers of patients recovered from COVID-19 with Spectral Domain Optical Coherence Tomography (SD-OCT) and compare these to healthy subjects.

Methods
Twenty-seven patients recovered from COVID-19, and age- and gender-matched 27 healthy controls were included in this study. Macular and peripapillary retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) were analyzed with SD-OCT 1 month (V1 visit) and 12 months (V2 visit) after negative result of reverse transcriptase-polymerase chain reaction test.

Results
Macular RNFL thickness in outer ring was thinner at V1 and V2 visits than healthy control (p = 0.049 and p = 0.005). Central and inferonasal quadrants of peripapillary RNFL thicknesses were reduced at V1 and V2 visits compared to controls (p = 0.001 and p = 0.024 for V1 visit; p = 0.001 and p = 0.006 for V2 visit). Thinning in ONL thickness in inner ring was observed at V1 and V2 visits than healthy subjects (p = 0.006 and p = 0.001).

Conclusion
Subclinical localized changes in macular and peripapillary RNFL and outer nuclear layer were demonstrated in early and 12-months follow-up after COVID-19 recovery.

Open access, https://link.springer.com/article/10.1007/s10792-022-02607-9

 

[SNT Gatchaman]

Although most long-COVID studies about survivors after both severe and mild disease demonstrate that long-term effects are independent from disease severity, as in our study, fully recovered patients with mild symptoms had retinal thickness alterations.

Abrishami et al. reported three months follow-up OCTA results on patients with no hospitalization history and Bilbao-Malavé V et al. declared 6-months followup OCTA results on COVID-19 bilateral pneumonia patients that COVID-19 appears to result in subclinical microvascular damage, which manifests in the retinal microcirculation detected by OCTA and that can result in clinically detectable features of micro-vasculopathy as a potential long-term sequelae of the disease.

Ischemic events in different retinal capillary beds after COVID-19 infection had been demonstrated by several studies. In our study, patients with mild symptoms recovered from COVID-19 had decrease in central and inferonasal quadrants of pRNFL thickness; ONL thickness in inner ring and mRNFL thickness in outer ring in early and long-term follow-up visits may indicate subclinic markers of ischemic events in retinal layers.

OCTA = optical coherence tomography angiography
pRNFL = peripapillary retinal nerve fibre layer
mRNFL = macular retinal nerve fibre layer
ONL = outer nuclear layer
See also Simple Anatomy of the Retina

 

[SNT Gatchaman]

See also Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease (2023)