Cumulative retardance (A, D, G), DOPU (B, E, H) and thresholded DOPU at 0.5, projected on top of the log intensity image (C, F, I). The threshold marks red DOPU values equal or lower than 0.5. B-scan is from Subject 13, an older subject with high retardance below the RPEBM complex and reaching values up to 180°. Consistently low-DOPU values are present in the RPE. Panels (D-F) are of an adjacent B-scan (separated by 47 μm) that sections the same drusen, panels (G-I) show a B-scan through a second, more shallow, drusen