Fig. 1

Analysis of choroidal vascular density using binarized en-face images. a Three-dimensional swept-source optical coherence tomography images were reconstructed as en-face images flattened with Bruch’s membrane. The yellow line shows where the subfoveal choroidal thickness is 50% level of total thickness. The white dotted-line shows the 3 × 3-mm square centered on the fovea after correction for magnification error using individual axial length. b Extracted 3 × 3-mm square en-face image. c En-face image after binarization. The black area is considered to be the choroidal vascular area, and the percentage within the region of interest is calculated as the choroidal vascular density