human_reference_atlas part of Homo sapiens organ part eye optic disc http://upload.wikimedia.org/wikipedia/commons/e/ed/Gray879.png optic disk optic nerve head MESH:D009898 UMLS:C0029127 UBERON:0001783 VHOG:0000551 The small blind spot on the surface of the retina. It is the point where the fibers of the retina leave the eye and become part of the optic nerve. [TFD][VHOG] EMAPA:18238 physiologic blind spot of mariotte (...) we reach the inescapable conclusion that the last common ancestor of jawless and jawed vertebrates already possessed an eye that was comparable to that of extant lampreys and gnathostomes. Accordingly, a vertebrate camera-like eye must have been present by the time that lampreys and gnathostomes diverged, around 500 Mya (reference 1); Although the eye varies greatly in adaptative details among vertebrates, its basic structure is the same in all. The human eye is representative of the design typical for a tetrapod (reference 2).[well established][VHOG] optic disk optic papilla physiologic blind spot SCTID:362518006 optic nerve head EHDAA:9077 MA:0000278 optic nerve disc AS CALOHA:TS-2153 uberon FMA:58634 The optic disc or optic nerve head is the location where ganglion cell axons exit the eye to form the optic nerve. There are no light sensitive rods or cones to respond to a light stimulus at this point. This causes a break in the visual field called 'the blind spot' or the 'physiological blind spot'. The optic nerve head in a normal human eye carries from 1 to 1.2 million neurons from the eye towards the brain. [WP,unvetted]. EFO:0001974 NCIT:C12760 Wikipedia:Optic_disc optic nerve head EHDAA2:0001307