Optic disc nargin anatomy

Schematic representation of border tissue (BT) configurations. A, Internally oblique: Border tissue extends internally from the posterior border tissue/scleral junction to fuse with Bruch's membrane (BM). B, Internally oblique with Bruch's membrane overhang. C, Externally oblique: Border tissue extends externally from the posterior border tissue/scleral junction to fuse with Bruch's membrane. D, Nonoblique: Border tissue is perpendicular relative to the scleral opening. For simplicity, the retinal pigment epithelium overlying Bruch's membrane is not shown. BMO = Bruch's membrane opening.