Fig. 1

Assessment of lamina cribrosa (LC) morphology. (A) The line connecting the two Bruch’s membrane openings (BMO) is selected as the reference plane. The anterior LC surface is manually depicted as an orange-color line. Connect each end of the orange-color line perpendicularly to the BMO connecting line (yellow dashed line). The distance between two intersection points is defined as ‘Line D’. The space surrounded by ‘Line D’, yellow-dotted line, and the border of the anterior LC surface was defined as ‘Area S’. The mean LC depth (mLCD) was computed by dividing ‘Area S’ by ‘Line D’. (B) LC thickness was defined as the perpendicular distance between the internal limiting membrane surface and the posterior laminar surface. The distance from the maximally depressed point (grey dashed line) of the optic nerve surface to the level of the posterior border of the LC was measured and adopted (green arrow). (C) The two vertical lines are drawn from the anterior laminar insertion (ALI) to the BMO reference plane. The two blue-dotted lines are drawn parallel to the BMO reference plane at each ALI. The cross points indicate the extent of the anterior laminar insertion depth (ALID). (D) The LC posterior displacement index represent the difference between the mLCD and the ALID (mLCD – ALID). The average ALID was calculated from the mean values of the nasal and temporal ALIDs.