Choriocapillary blood propagation in normal volunteers and in patients with central serous chorioretinopathy.

Background/aims: To evaluate early choroidal vascular dye-filling and dye propagation patterns in normal subjects and in patients with central serous chorioretinopathy (CSC) using indocyanine green (ICG) angiography.

Methods: Seventeen healthy volunteers (21-81 years old) and six patients with CSC were included. ICG angiography was performed using a modified Topcon ICG video-camera system. Subtracted images were made using the early ICG frames at a time interval of 0.12 s. Ninety frames of time-sequential images for 3 s starting from the initial dye appearance in the choroid were prepared to construct an animated video.

Results: The animated video demonstrated dye-filling and propagation patterns at the level of the choroid-choriocapillaris. In normal young volunteers, the initial phase of dye filling appeared as a uniform patchy fluorescence in the sub-foveal area, and then spread evenly in a centrifugal manner in all directions in a wave-like, pulsed fashion towards the equator. In normal older volunteers, the initial phase was similar to that in young volunteers, but centrifugal flow propagation of fluorescence towards the periphery showed an uneven progression and border. In patients with CSC, the initial dye showed a multiple patchy dye appearance with a significant time delay and loss of the centrifugal extension pattern.

Conclusion: Using this new approach, various choroidal dye propagation patterns were observed in normal volunteers and in patients with CSC. A video of subtracted images allowed evaluation of the dynamics of dye propagation in the choroid-choriocapillaris.