Analysis of microvascular and neurodegenerative complications of mild COVID-19, 2022, Kolkedi et al

Abstract
Purpose

To examine retinal and corneal neurodegenerative and retinal microvascular changes in patients after mild or asymptomatic COVID-19 disease compared to age-matched controls.

Methods
Thirty-five (35) patients after PCR-proven SARS-CoV-2 infection and 28 age-matched controls were enrolled. Swept-source optical coherence tomography (OCT), OCT angiography, and in vivo corneal confocal microscopy were performed in both groups. Corneal subbasal nerve plexus was quantified. Vessel density for superficial (SCP) and deep capillary plexus (DCP) and structural OCT parameters were recorded.

Results
Significantly lower nerve branch density (P = 0.0004), nerve fiber area (P = 0.0001), nerve fiber density (P = 0.0009), nerve fiber length (P < 0.0001), and total nerve branch density (P = 0.002) values were observed in patients after COVID-19 compared to healthy controls. VD of the temporal SCP was significantly different between the two groups (P = 0.019). No other SCP and DCP vessel density parameter differed significantly between the two groups.

Conclusions
Our results suggest that peripheral neurodegenerative changes may occur even after mild or asymptomatic SARS-CoV-2 infection. No relevant microvascular changes were seen with OCT angiography and structural OCT parameters did not show any signs of optic neuropathy in post-COVID patients. In vivo confocal microscopy seems to be an important tool in monitoring peripheral neuropathy in patients after COVID-19.




Open access: https://link.springer.com/article/10.1007/s00417-022-05623-8

 

Mild disease convalescents.

 

So they aren't able to replicate the findings of Hohberger and other groups https://www.s4me.info/threads/persi...mmation-2023-kuchler-et-al.33504/#post-486399, but this might be due to "in vivo confocal microscopy could reveal early corneal microstructural and subbasal nerve fiber changes in patients with metabolic diseases before the development of ophthalmoscopic changes". Indeed they are only looking at patients with a very short disease duration (2 weeks to 6 months). So essentially they are looking at both acute Covid and Long Covid, but mix it together. It seems more longitudinal data would be necessary and shouldn't have been hard to get.

 

I can't tell if they really include recovered people, but if they don't that would essentially mean that every patient has at most 2 symptoms (with most patients only having fever as only symptom) which really isn't a lot and probably wouldn't be very different from controls. Add on top of that the main symptom is fever, which is just the sign of an acute infection and this study reads itself very differently to what the authors state.

At least this study is a slightly older study, as such mistakes would be inexcusable today.