Change in retinal vessel diameter and choroidal thickness in patients with severe COVID-19: Change In Retinal Parameters In Patients With Severe COVID-19.

PURPOSE: To compare the differences in retinal vascular structure and choroidal thickness between the active disease and post-recovery periods in COVID-19 patients and healthy controls. MATERIAL AND METHODS: This prospective, cross-sectional study included 30 eyes from 30 patients with severe COVID-19 and 30 eyes of 30 sex-matched healthy controls. Central macular thickness (CMT), subfoveal choroidal thickness (CT) and retinal vascular changes of patients were measured after positive polymerase chain reaction (PCR) (where the patient had COVID-19-related symptoms) and then three months after two negative PCRs. Laboratory parameters, including C-reactive protein and d-dimer levels, were also recorded. RESULTS: The mean age of the patients was 47.90 ± 9.06 years in patients group, 49.07 ± 8.41 years in control goups (p = 0.467). In terms of choroidal thicknesses subfoveal, nasal and temporal region were significantly higher in the active disease period than control group (p = 0.019, p = 0.036, p = 0.003, respectively). When the after recovery period was compared with the control group in terms of choroidal thickness, although the choroidal thickness was higher in all regions, this difference was not found statistically significant. There was no statistically significant difference in CMT between groups (p = 0.506).The mean venous and arterial wall thicknesses were significantly higher in the active period than after recovery (p = 0.023, p = 0.013, respectively) but there were no differences between after recovery and control groups in the pairwise comparison (p = 0.851, p = 0.715, respectively). CONCLUSION: In patients with severe COVID-19, there are changes in thickness of the choroid and retinal vessel walls. While vascular wall thickness increases due to inflammation, the absence of lumen changes may be associated with hemodynamic variables.