Mechanisms of retinal damage in patients with COVID-19

Long-term follow-up of choroidal changes following COVID-19 infection: analysis of choroidal thickness and choroidal vascularity index

OBJECTIVE

To investigate subclinical choroidal involvement in patients with systemic coronavirus disease 2019 (COVID-19) infection and evaluate its long-term course.

MATERIALS AND METHODS

This prospective, longitudinal study included 32 eyes of 16 COVID-19 patients and 34 eyes of 17 age-matched healthy control subjects. All the participants had a detailed ophthalmologic assessment, including visual acuity assessment, slit-lamp examination, and indirect ophthalmoscopy. Enhanced depth optical coherence tomography imaging of the posterior pole and peripapillary region was performed in the early (days 15-40) and late (ninth month) postinfectious periods. Choroidal vascularity index (CVI) was calculated using ImageJ software (National Institutes of Health, Bethesda, Md.).

RESULTS

None of the patients had any examination finding associated with the ocular involvement of COVID-19. Subfoveal choroidal thickness (SFCT) decreased significantly in the early postinfectious period compared with the healthy control individuals (p = 0.045). SFCT increased significantly in the late postinfectious period compared with the early period (p = 0.002), and the difference between patients and control individuals became statistically insignificant (p = 0.362). There was a similar trend for the peripapillary choroidal thickness measurements. CVI remained unchanged (p = 0.721) despite the significant decrease in SFCT and total choroidal area (p = 0.042), indicating that this decrease occurred both in choroidal stroma and in blood vessels. CVI remained unchanged in the late postinfectious period (p = 0.575) compared with the early period, indicating that recovery occurred in the entire choroidal tissue.

CONCLUSION

This study demonstrates that choroidal thickness was reduced in all measured areas and that this decrease affected all choroidal layers. This choroidopathy was reversible and recovered in the ninth postinfectious month.

Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels

To evaluate retinal and choroidal thickness with optical coherence tomography (OCT) to detect retinal and choroidal pathologies in coronavirus disease 2019 (COVID-19) patients with high D-dimer levels. Thirty patients who were hospitalized in the intensive care unit due to severe acute respiratory syndrome coronavirus 2 and whose D-dimer levels were high during this period, who applied to the internal medicine outpatient clinic between 15 and 30 days after discharge, and 30 healthy volunteers with similar age and gender as the control group was included in the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated using optical coherence tomography. Statistical analysis of the study data demonstrated that there was no significant difference between the groups in terms of age or gender (p > 0.05). There was also no statistically significant difference between the groups in terms of central foveal thickness, central choroidal thickness, or nasal 500, nasal 1500, temporal 500, or temporal 500 micron distances (p > 0.05 for all parameters). Choroidal and retinal vascular thicknesses were not affected in the short term in COVID-19 patients hospitalized in the intensive care unit.