Choriocapillaris Flow Deficit in the Fellow Eyes of Patients with Central Serous Chorioretinopathy

Abstract Background: A thickened choroid and hyperpermeability are thought to play an important role in Central Serous Cho-rioretinopathy (CSC). As CSC is part of the pachychoroid disease spectrum, which includes pachychoroid pigment epitheliopathy (PPE), a proportion of the "unaffected" fellow eyes evaluated may present PPE. The development of optical coherence tomography angiography (OCTA) has provided new insights into the retinal and choroidal microvasculature allowing individual vascular plexi to be evaluated at extremely high resolution. Aim of Study: The goal of the study is to examine the choriocapillaris (CC) flow characteristics based on the under-lying choroidal vasculature in fellow eyes of patients with central serous chorioretinopathy (CSC). Methods: Clinical records of fellow eyes of patients with unilateral CSC without fundus findings and control eyes of otherwise healthy individuals, diagnosed at Kafrelshiekh and Tanta university hospitals from August 2021 to September 2022, were retrospectively analyzed. Optical coherence tom-ography (OCT) angiography images of the choriocapillaris slab were binarized and according to the underlying choroidal beds, we examined the flow void area and mean vascular density of the choriocapillaris between the CSC and control groups. Results: The CSC group choriocapillaris mean vascular density did not differ from the control group (p=0.289) in any significant way. In the CSC group, the flow void area was observed more frequently (59.6%) than in the control group (29.8%; p=0.002). Greater macular choroidal thickness was linked to the presence of the flow void area in the CSC group (p=0.004). Conclusion: The distribution of the underlying choroidal vessels was related to where the flow void area of the chori-ocapillaris was located. This implies that choriocapillaris perfusion in pachychoroid eyes may be impacted by the underlying choroidal vessels.