We investigated the relationship between microstructure of β-parapapillary atrophy (β-ppA) and morphologic features of optic nerve head (onH) and posterior pole in highly myopic eyes. eighty-nine highly myopic eyes were included in this study. Bruch's membrane opening (BMo) area, lamina cribrosa (Lc) thickness, anterior laminar depth, peripapillary and subfoveal choroidal thickness (ct), macular Bruch's membrane (BM) length, and width of β-ppA with and without Bruch's membrane (ppA +BM and ppA −BM ) were evaluated. The mean age and axial length of the included subjects were 26.88 ± 2.44 years and 27.03 ± 0.88 mm, respectively. The width of PPA −BM was larger with increasing BMo area (P = 0.001), whereas the BMO area was not associated with the width of PPA +BM . the large ppA +BM was significantly related to a thinner LC (P = 0.003), deeper anterior lamina surface (P < 0.001), longer macular BM length (P = 0.008), and thinner temporal peripapillary CT (P = 0.034). We found that the morphologic features of the ONH and posterior pole in highly myopic eyes were different based on the microstructure of β-ppA. Whether these features are linked to the development of glaucoma in myopic eyes should be investigated in future studies.Classic funduscopic β-parapapillary atrophy (β-PPA) is a region of visible large choroidal vessels and sclera due to the lack of retinal pigment epithelium (RPE). β-PPA can be histologically subclassified based on the presence or absence of Bruch's membrane (BM): β-PPA with BM (PPA +BM ; β zone) and β-PPA without BM (PPA −BM ; γ zone). It has been known that PPA +BM might be due to age-related atrophy of the RPE and associated with the development of glaucoma 1-4 . Whereas, PPA −BM has been considered as a result of mechanical stretching in the peripapillary sclera and border tissue during axial elongation; hence a significant association between axial length and PPA −BM width has been consistently reported 1-3,5 . However, we previously reported that PPA +BM was also found in 20-30-year-old myopia subjects and suggested that PPA +BM in young myopia patients might be related to axial elongation, not age-related atrophy 6 . In accordance with our report, Lee et al. 7 recently found an enlargement of PPA +BM as myopia progressed and proposed that PPA +BM found in children might be an entirely different entity from PPA +BM in elderly individuals, sharing an etiology with PPA −BM .Several factors might contribute to β-PPA development during axial elongation, but the etiology of PPA +BM and PPA −BM enlargement remains elusive so far. It is unclear why some myopia patients exhibit only PPA −BM , whereas others with a similar degree of myopia exhibit both PPA +BM and PPA −BM . In this study, we hypothesized that morphologic features of the optic nerve head (ONH) and the posterior pole might give clues to the mechanisms of differential developments of β-PPA in myopic eyes. Therefore, the purpose of this work was to investigate the relationship between microstructure of β-PPA and the morphologic featur...