part_of part of part of develops_from develops from developmentally induced by developmentally_induced_by contributes to morphology of anatomical entity anatomical entity connected anatomical structure anatomical structure lens of camera-type eye ZFA:0000035 lenses CALOHA:TS-0545 AAO:0010348 RETIRED_EHDAA2:0000975 The eye of the adult lamprey is remarkably similar to our own, and it possesses numerous features (including the expression of opsin genes) that are very similar to those of the eyes of jawed vertebrates. The lamprey's camera-like eye has a lens, an iris and extra-ocular muscles (five of them, unlike the eyes of jawed vertebrates, which have six), although it lacks intra-ocular muscles. Its retina also has a structure very similar to that of the retinas of other vertebrates, with three nuclear layers comprised of the cell bodies of photoreceptors and bipolar, horizontal, amacrine and ganglion cells. The southern hemisphere lamprey, Geotria australis, possesses five morphological classes of retinal photoreceptor and five classes of opsin, each of which is closely related to the opsins of jawed vertebrates. Given these similarities, 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.[well established][VHOG] FMA:58241 This class excludes compound eye corneal lenses. MA:0000275 TAO:0000035 BTO:0000723 EHDAA:9057 OpenCyc:Mx4rvVj0fZwpEbGdrcN5Y29ycA XAO:0000008 MAT:0000141 SCTID:181169005 eye lens EV:0100343 lens lens crystallina UBERON:0000965 UMLS:C0023317 uberon VHOG:0000169 MESH:A09.371.509 EMAPA:17838 crystalline lens NCIT:C12743 camera-type eye lens MIAA:0000141 The lens is avascular and nourished by diffusion from the aqueous and vitreous Wikipedia:Lens_(anatomy) ocular lens Transparent part of camera-type eye that helps to refract light to be focused on the retina. anterior segment of eyeball vasculature retinal neural layer ectoderm-derived structure transparent eye structure lens vesicle