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

Abstract

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