The scleral bed around the optic disc commonly formed a flat surface (
Fig. 3B). However, the sloping edge of the scleral bed (
Fig. 3D) was found in 62 (68.9%) of 90 eyes with PPA-β and 1 (3.3%) of 30 eyes without PPA-β (
P < 0.0001, Fisher's exact test,
Table 2). There were no significant differences in sex, age, refractive error, axial length, and IOP between eyes with a sloping edge and those without (
P > 0.10, Mann-Whitney test). Step configuration of the peripapillary scleral bed, in which a flat area was followed by a steep slope and then another flat area (
Fig. 3F), was found in 6 (6.7%) of 90 eyes with PPA-β and in 0 (0%) of 30 without PPA-β (
P = 0.3348). Step configuration was found only in PPA-β located in the inferotemporal half of the optic disc. Eyes with step configuration had more myopic refraction (−3.3 ± 1.7 D vs. −0.3 ± 1.7 D,
P = 0.0014) and longer axial length than those without it (24.94 ± 1.26 mm vs. 23.69 ± 0.99 mm,
P = 0.0105). Hump- and wedge-shaped appearances of the RPE–Bruch's membrane complex were also found in the edge of the optic disc. A hump-shaped appearance resembling a road hump continued from the RPE layer in the OCT image, corresponding to the narrow crescent of hyperpigmentation on the color fundus photographs (
Figs. 3G,
3H), and was found in 8 (8.9%) of 90 eyes with PPA-β and 11 (36.7%) of 30 eyes without PPA-β (
P = 0.0009). The wedge-shaped appearance was seen as an upward extension of the RPE–Bruch's membrane complex at the edge of the optic disc (
Fig. 3J), which was observed in 5 (5.6%) of 90 eyes with PPA-β and 1 (3.3%) of 30 eyes without PPA-β (
P = 1.00). No significant difference was found between eyes with and without either wedge- or hump-shaped appearance for sex, age, refractive error, axial length, and IOP (
P > 0.3).