Optic vesicle is an outgrowth of the diencephalon.
Reciprocal induction occurs between the optic vesicle and the overlying surface ectoderm. A lens vesicle is formed. The optic vesicle invaginates to form the optic cup. The lens vesicle induces the surface ectoderm to form the cornea. The Pax6 gene is expressed in cells of the forebrain.