FIGURE 4.

The anatomic change during myopic tilted disc development. Panels (A,C) show the initial optic disc on fundus photograph and optical coherence tomography (OCT) horizontal scan, respectively. The black circle outside the optic disc indicates the Bruch’s membrane opening (BMO) windows (A,C). The blue lines in Panels (C,D) indicate Bruch’s membrane (BM) layer, the black lines indicate the sclera of the eyeball, and the orange planes in between them represent the lamina cribrosa (LC). Panels (B,D) show the anatomic change after myopic progression. After the posterior scleral deformation, the tensile strength of the sclera is conducted to the LC. The LC is dragged nasally under the BMO window, along with the blood vessels that pass through the LC (B). This nasal shifting and tilting of LC lead to misalignment of BM and formation of peripapillary atrophy. During the optic disc tilting, the distance between BMO remains relatively unchanged (B,D). In the cross-sectional view (D), the posterior protrusion of the sclera stretches the LC toward the deepest point of eyeball, resulting in a more oval disc and disc torsion appearance on the fundus photograph (B).