Figure 1

Schematic drawing of three openings in optic nerve head (ONH) canal. The black lines indicate the Bruch’s membrane (BM) with central opening (BMO). The blue lines indicate the sclera and its anterior opening, defined as the anterior scleral opening (ASCO; blue circle). The lamina cribrosa (LC; purple cylinder) is located at a lower level than the ASCO is. The axons passing through the ONH canal are drawn as yellow fibers. The central retinal vascular trunk (CRVT; red line) also passes through the ONH canal. The optic nerve sheath (gray line) is anchored to the posterior sclera near the ONH canal. The alignments among the BMO, ASCO, and LC are known to change during eyeball expansion. This study was designed to compare the ASCO and CRVT (a surrogate of LC position) offsets from the BMO.