Practice question

Temporal sequence of vertebrate eye development initiates with optic vesicle evagination from diencephalic wall. Early anterior neural plate forms eye field expressing Rx and Pax6, then bilateral evagination produces optic vesicles extending toward surface ectoderm. Contact with competent head ectoderm induces lens placode, subsequently lens vesicle invaginates, simultaneously vesicle invaginates into optic cup forming neural retina and pigmented epithelium. Thus optic vesicle precedes lens vesicle, corneal ectoderm, and pigmented retina differentiation. Its emergence represents first morphological indication of eye development orchestrating subsequent inductive interactions and patterning events.