Abstract
Purpose :
To measure the innervation of the corneal subbasal nerve plexus of Covid-19 patients and compare the results with values of healthy patients.
Methods :
A prospective, observational study was conducted analyzing 39 eyes of patients who had overcome Covid -19 and 46 eyes of healthy volunteers included as a control group (verified by antibody analysis and negative qPCR result) which underwent in vivo confocal microscopy with Rodstock Cornea Module© attached to Heildelberg HRT3©. Ocular surgery procedures, previous ocular infections or systemic diseases that could cause alteration in corneal innervation were exclusion criteria. At least 5 non overlapping images of each eye were selected and only one eye of each patient was included in the study. Following sub basal nervous plexus parameters were measured with ACC Metrics© software: Corneal Nerve Fiber Density (CNFD), Corneal Nerve Branch Density (CNBD), Corneal Nerve Fiber Length (CNFL), Corneal Total Branch Density (CTBD), Corneal Nerve Fiber Area (CNFA), Corneal Nerve Fractal Dimension (CNFrD). Data analysis was performed with SPSS® software for Windows 22.0 (SPSS® Inc, Chicago, IL.). The differences of age and sex between groups were checked with T-test and chi-square tests. The normality of the sample was checked with the Shapiro-Wilk test and the results were compared with the T test or the Man-Whitney U test based on the distribution of the data. The differences were considered statistically significant for p<0.05.
Results :
There was no difference in the sex distribution between the groups (p= 0.248). The average age (± standard error) was 46.61±17.55 years for Covid-19 patients and 43.11±16.95 years for healthy control group (p=0.353) The mean of the analyzed variables (± standard error) from Covid-19 patients versus control group were CNFD: 16.09±6.92 and 23.03±8.31 fibers/mm2 (p=0,00008), CNBD: 21.93±15.37 and 28.93±17.84 branches/mm2 (p=0.064), CNFL: 11.61±3.61 and 14.05±3.71 mm/mm2 (p=0.002), CTBD: 38.48±20.02 and 43.29 ± 23.94 (p=0.41), CNFA: 0.0057±0.0017 and 0.006±0.0023 mm2/mm2 (p=0.853), CNFrD: 1.46±0.041 and 1.47±0.037 (p=0.007).
Conclusions :
According to the data obtained, corneal subbasal nerve plexus is decreased in Covid-19 patients compared to the healthy control group, statistically significant for density, length, and fractal dimension. The results show the presence of possible small fiber neuropathy induced by Covid–19 disease.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.