Fig. 1.

A schematic explanation of the methodology used for measuring the lamina cribrosa tilt angles (LCTA) against the Bruch’s membrane opening (BMO). Top left: lines were drawn in the superior temporal (ST) to inferior nasal (IN) and inferior temporal (IT) to superior nasal (SN) directions (±45° rotation with the horizontal line). Bottom left, white dotted line: fundus photography (top center and right) volume image sectioned at the level of IT to SN direction and ST to IN direction reconstructed from the 3D OCT dataset (bottom center and right) B-scans along IT to SN and ST to IN directions. A line (red dotted line) connecting the proximal tips of Bruch’s membrane on each side of the ON head on the cross-sectional SD-OCT image was drawn and set as the BMO reference plane. LCTA was defined as the angle measured between the inner edge of the BMO plane and the best-fitting line (red dotted line) for the anterior LC plane