Optic disc tilt is caused by the posterior bulge of the bulbous wall of the eye with high myopia, and the optic nerve enters the bulb obliquely, resulting in a posterior displacement of one side of the optic disc (mostly the temporal side), which causes the optic disc to lose its normal slightly vertical ellipse and become a prominent vertical (or lateral, oblique) ellipse, or even skip-like shape, under the examining glasses. Degenerative myopia is characterized by a tilted optic disk and myopic arcs. The optic nerve enters the globe obliquely due to the posterior projection of the wall of the eye in high myopia. One side of the optic disc (mostly the temporal side) is displaced posteriorly, causing the disc to lose its normal slightly vertical oval shape and become a prominent vertical (or lateral, oblique) oval, or even skip-shaped, under the examining lens. A crescent-shaped spot, called the myopic arc (conus, or extended conus), is attached to the side of the disc that is displaced backward. The contralateral side of the myopic conus has a slightly brown, blurred, crested, upwardly elevated supertraction conus at the edge of the optic disk. The stretching myopic conus is white medially, due to scleral exposure, and light brown laterally, due to loss of pigmented epithelium and choroidal exposure. The lateral realm of the myopic arc is well defined, but is often contiguous with the area of atrophy at the posterior pole. The myopic arc is located temporally to the optic disk in most cases, but also supratemporally or inferotemporally. More rarely, it is located nasally or inferiorly; the former is called the inversive conus; the latter is called the Fuchs conus. When the temporal myopic arc extends outward, upward, and downward, it can encircle the entire periphery of the optic disc, which is known as peripapillary chorioretinal atrophy (peripapillary chorioretinal atrophy). Genetics has been recognized as a major factor in optic disc tilt. The mode of inheritance ranges from autosomal recessive to dominant and X-linked, with a high degree of genetic heterogeneity. In addition to heredity, acquired environments such as general health, living environment, personal habits, and prolonged near-eye work, etc., may contribute to the increase in myopia.