How does Covid-19 affect the choroidal structures at the early post-infectious period?

Abstract

To evaluate choroidal thickness (CT) and choroidal vascularity index (CVI) in patients recovered from COVID-19 using enhanced depth imaging optical coherence tomography in the early postinfectious period. Sixty-five patients recovered from COVID-19 and 72 healthy subjects were included in the study. A full ophthalmic examination including best-corrected visual acuity (BCVA), slit lamp biomicroscopy, and dilated fundus examination was performed. CT was measured at 3 points as follows: subfoveal, 1000μm nasal and temporal to the fovea. The total choroidal area (TCA), luminal area (LA), stromal area (SA), and CVI were measured with Image-J. The mean age was 39.09±11.27 years in the COVID-19 group and 39.61±11.43 years in the control group. The mean time from the first positive RT-PCR was 49.54±26.82 days (range 18-120) in the COVID-19 group. No statistically significant difference was detected between the groups with regard to axial length, spherical equivalent, and BCVA (all P>0.05). CT was found to be lower in the COVID-19 group compared to the control group in all quadrants, but this difference was not significant (all P>0.05). The mean TCA, LA, and CVI were statistically significantly reduced in the COVID-19 group (all P<0.001); however, SA showed no statistically significant difference (P=0.064). In asymptomatic or mild COVID-19, CVI and LA decrease significantly, while CT thins in the early postinfectious period but not significantly.