Investigation of changes in retinal vascular parameters and choroidal vascular index values during the early recovery period of COVID-19: The COVID-OCTA study.

Background: COVID-19 effects microvasculature in many tissues. This study investigated whether the choroidal structure is also affected.

Methods: This cross-sectional study included 80 patients with COVID-19 and the same number of age- and gender-matched healthy individuals. All participants' right eye measurements were examined. Optical coherence tomography angiography (OCTA) was used for imaging. Otherwise, two independent researchers used the Choroidal vascular index (CVI) for choroidal parameters calculation.

Results: Superior and deep flow values were lower in the COVID-19 group than in the control group, and vascular density (VD) values were lower in all regions in this group. Except for the superior mean VD, there was no statistically significant difference (p = 0.003). However, the COVID-19 group had significantly lower subfoveal choroidal thickness (SFChT) measurements than the control group (p = 0.001). In addition, no significant difference was observed between the groups in evaluating mean CVI values (p>0.05).

Conclusion: Noninvasive diagnostic tools such as OCTA and EDI-OCT can be used to monitor early changes in diseases affecting microvessels, such as from COVID-19.