Figure 1.

Definition of BM semi-landmarks and directly calculated shape parameters using OCT B-scans of optic nerve heads. (A) The 8 semi-landmarks (circles) spaced at 220 μm (grids) along the BM on either side of the optic nerve head were digitized. Their coordinates served as the input for geometric morphometric shape analysis. (B) Geometric transformations applied to semi-landmarks identified on the OCT image were used to calculate the BM opening (BMO) width and the displacement of the temporal (D_t) and nasal (D_n) BM margins from a secant line drawn between the two most lateral semi-landmarks.