Corneal confocal microscopic parameters in COVID-19 patients and healthy control subjects
| CNFD (no./mm2) | CNBD (no./mm2) | CNFL (mm/mm2) | Total DC density (no./mm2) | Mature DC density (no./mm2) | Immature DC density (no./mm2) | |
| Healthy control subjects (n=30) | 33.5±6.9 | 50.7±19.5 | 19.2±3.7 | 12.7 (0–30.4) | 0 (0–4.2) | 12.7 (0–24.7) |
| Post-COVID patients (n=40) | 31.0±7.0 | 39.5±18.6 | 17.4±4.6 | 39.5 (13.2–92.5) | 7.3 (0–16.7) | 30.6 (8.9–69.9) |
| With neurological symptoms at 4 weeks (n=22) | 28.7±6.1 | 36.1±16.9 | 15.9±4.2 | 35.1 (9.0–85.8) | 7.3 (0–18.7) | 22.7 (4.4–65.5) |
| Without neurological symptoms at 4 weeks (n=18) | 33.9±7.1 | 43.7±20.2 | 19.3±4.5 | 53.5 (22.0–95.7) | 7.3 (0–15.1) | 33.5 (15.2–80.3) |
| P values | ||||||
| Post-COVID vs control | 0.141* | 0.017* | 0.080* | 0.001† | <0.001† | 0.002† |
| With neurological symptoms vs control | 0.032‡ | 0.020‡ | 0.012‡ | 0.046§ | 0.003§ | 0.101§ |
| Without neurological symptoms vs control | 0.981‡ | 0.438‡ | 0.998‡ | 0.003§ | 0.010§ | 0.007§ |
| With vs without neurological symptoms | 0.044‡ | 0.412‡ | 0.027‡ | >0.999§ | >0.999§ | >0.999§ |
Data are expressed as mean±SD for CNFD, CNBD and CNFL, and median (IQR) for DC density. The bold p values represent statistically significant differences.
*Independent samples t-test.
†Mann-Whitney U test.
‡One-way ANOVA test followed by Tukey test.
§Kruskal-Wallis test followed by Dunn’s test with adjusted p values using Benjamini-Hochberg procedure.
ANOVA, analysis of variance; CNBD, corneal nerve branch density; CNFD, corneal nerve fibre density; CNFL, corneal nerve fibre length; DC, dendritic cells.