(...) an essentially similar sequence of events occurs during the embryonic development of the vertebrate eye. The eye initially develops as a single median evagination of the diencephalon that soon bifurcates to form the paired optic vesicles. As each optic vesicle grows towards the body surface, its proximal part narrows as the optic stalk, and its distal part invaginates to form a two-layered optic cup. (...) The optic cup induces the overlying surface ectoderm first to thicken as a lens placode and then to invaginate and form a lens vesicle that differentiates into the lens.[well established][VHOG]

uberon

lens cavity

cavity of lens

UBERON:0005688