Fig. 1

Enhanced depth imaging (EDI) optical coherence tomography images of a patient with RP. The light areas in choroid are the stromal areas and the dark areas are the luminal areas A. the total choroidal area (TCA) was determined as the area between RPE and the choroid-sclera junction in the subfoveal choroid. The examined area was set to be 3000 μm wide B, C. the average brightness of the three choroidal vessels with lumens larger than 100 μm was set as the minimum value of the image reflectivity in brightness/contrast tool D. the image was converted to a binary image using Niblack auto local threshold tool E, F. color threshold tool was applied to specify luminal areas from stromal areas