Three-Dimensional Characteristics of Choroidal Vasculature Associated With Filling Delay in Central Serous Chorioretinopathy.

PURPOSE: The purpose of this study was to investigate circulatory disorders in central serous chorioretinopathy (CSC), we analyzed the three-dimensional (3D) structure of the choroidal vessels in filling delays seen on indocyanine green angiography (ICGA) images.

METHODS

We conducted structural optical coherence tomography (structural OCT) and OCT angiography (OCTA) with swept-source OCT (SS-OCT) and ICGA in 30 eyes with CSC. We aligned the en face z-projection images of structural OCT with the venous-phase ICGA images by incorporating deformation adjustments. Image-enhancement processes, including attenuation correction and local contrast enhancement, were applied to the structural OCT and OCTA images to improve visibility of deep choroidal structures. We used public-domain 3D image analysis software to examine choroidal structures in venous-phase filling delays.

RESULTS

In the inner Haller's layer, structural OCT images showed occult vessels, that is, dilated blood vessels not delineated by ICGA in the filling delay region in 22 eyes (73%). These vessels had lower signal intensity than the surrounding blood vessels in both structural OCT and OCTA images. In the outer Haller's layer of the filling delay area, the entry points of penetrating vessels were detected in 29 eyes (97%), and direct intersections with penetrating vessels were seen in 7 (33%) of 22 eyes showing occult vessels. Late-phase ICGA images showed hyperpermeability corresponding to the filling delays. Angle and mean curvature at the entry point of the penetrating vessel increased in CSC, especially in the filling delay (P < 0.001).

CONCLUSIONS

In CSC, dilated vessels not visible on ICGA are present in areas with venous-phase filling delays. Alterations in the choroidal arterioles may contribute to the formation of these vessels.