part of part of extends_fibers_into organ part cranial nerve II retina optic disc optic disk MESH:D009898 UBERON:0001783 VHOG:0000551 EMAPA:18238 physiologic blind spot of mariotte optic disk optic papilla physiologic blind spot SCTID:362518006 optic nerve head EHDAA:9077 MA:0000278 optic nerve disc CALOHA:TS-2153 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 EHDAA2:0001307