Chung YR, et al. - This study was designed in order to investigate the subfoveal choroidal thickness in the eyes with active central serous chorioretinopathy (CSC) and after resolution of CSC and to analyze Haller's layer, Sattler's layer, and large choroidal vessel diameter. The subfoveal choroidal thickness and thickness of Haller's layer declined following the resolution of CSC. However, about half of the total thickness changes in the choroid were accounted by the reduced diameter of subfoveal choroidal vessels. Hence, in the thickening of the choroid during CSC and possibly in the pathogenesis and progression of CSC, nonvascular smooth muscle cells possibly played a role.