Figure 2.

Processing and Quantification of Optical Coherence Tomography Angiography Images of the Superficial and Deep Capillary Plexus: Vessel Density, Vessel Length Density, and Geometric Perfusion Deficits. (A, B) Averaged OCTA images of the superficial capillary plexus (SCP) and deep capillary plexus (DCP), respectively. (C, D) Binarized images of the SCP and DCP layers obtained using the Huang thresholding method, which converts the grayscale OCTA images into binary images where vessels appear as white areas and the background as black. These images are used to calculate vessel density by measuring the proportion of vessel area relative to the total image area. (E, F) Skeletonized images of the SCP and DCP layers, where vessel structures are reduced to single-pixel-wide lines while preserving their original shape. This processing allows for the quantification of vessel length density by measuring the total vessel length. (G, H) Images of the SCP and DCP layers processed to identify areas that are at least 30 µm away from the nearest vessel (red areas). These images are used to calculate geometric perfusion deficits by analyzing the perfusion-free areas relative to the total area, excluding the foveal avascular zone (FAZ). In the DCP layer, an additional step is performed to subtract large vessels before the final measurements.