Figure 1.
Automatic segmentation of Haller's and Sattler's layer for thickness mapping.
OCT B-scan (A) visualizes the segmentation lines for the retina between the ILM (green line) and the RBC complex and the identified vessel voxels are visualized in red (B). The choroid is located between the RBC complex and the sclera (yellow line). Probability cones (small rectangle enlarged) were drawn to demonstrate expected vessel core position. The cone projections are in 3D, butthe concept is presented in two dimensions. The ratio of volume voxels to surface voxels that were generated was plotted for a 1×1 degree volume. This volume consists of 14 B-scans and is represented by the 5 B-scans in the yellow rectangle (C). The plot is used for determining the border between the two sublayers by detecting the largest ratio as Haller's layer vessels (H),and the local minimum is the border (arrow) to Sattler's layer (S). Plots were used to generate thickness maps for Sattler's (D) and Haller's layers (E) across the scan area.
Figure 2.
Repeatability of Sattler's and Haller's layer thickness mapping and ETDRS measurements in non-neovascular AMD.
Sattler's layer and Haller's layer are color mapped. Imaging was performed twice at the same session (left and middle column) and on a different day (right column). The vessel segmentation and indocyanine green angiography images of this eye are depicted in Figure 3.
Table 1.
Average repeated choroidalsublayer thickness measurements for the central submacular field (CSM) and the total macular field ( µm).
Table 2.
Intraclass correlations (ICC) and coefficients of repeatability (CR).
Figure 3.
Segmentation validation in a non-neovascular AMD eye via a comparison of the segmented vasculature with indocyanine green angiography (ICGA).
Early phase (A) and middle phase (B) angiography images show the ICGAresolution for choroidal vascular imaging. OCT B-scan centered on the fovea (C), and segmented areasare marked in red (D) to visualize vessel segmentation. The OCT B-scan (D) shows the segmentation lines for the retina between the ILM (green line) and the RBC complex. The choroid is located between the RBC complex and the sclera (yellow line). En face views are locatedat the inner choroid (E), the outer choroid (F) and the entire choroid (G) to demonstrate captured vessels and depth information. The bars represent 1 mm.
Table 3.
Automated calculated mean for healthy Sattler's and Haller's layer thickness across the Early Treatment Diabetic Retinopathy Study grid ( µm).