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

Hepokur, Mustafa; Gunes, Medine; Durmus, Ebubekir; Aykut, Veysel; Esen, Fehim; Oguz, Halit

PURPOSE: The aim of this study was to investigate subclinical choroidal involvement in patients with systemic 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 of the participants had a detailed ophthalmological 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 at the early (days 15-40) and late (9(th) month) postinfectious periods. Choroidal vascularity index (CVI) was calculated using Image-J software. RESULTS: None of the patients had any examination finding associated with the ocular involvement of COVID-19. Subfoveal choroidal thickness (SFCT) significantly decreased at the early postinfectious period compared to healthy controls (p=0.045). SFCT significantly increased at the late postinfectious period compared to early (p=0.002) and the difference between the patients and controls 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 (TCA, p=0.042), indicating that this decrease occurred both in choroidal stroma and blood vessels. CVI remained unchanged in the late postinfectious period (p=0.575) compared to the early period, indicating that recovery occurred in the entire choroidal tissue. CONCLUSION: This study demonstrated that choroidal thickness was reduced in all measured areas and this decrease affected all choroidal layers. This choroidopathy was reversible and recovered at the 9(th) postinfectious month.