EMBRYOLOGY

Two diverticula appear from either side of  neural tube. They reach surface ectoderm. These diverticula thickens to form optic plate. The neural tube closes. Here form optic vesicle, Vesicle invaginates form below to form optic cup which is deficient inferiorly called embryonic fissure.The outer layer of optic cup forms retinal pigment epithelium and inner layer forms neurosensory retina. The hyaloid vessels grow through fissure to supply lens and other structures. Near optic vesicle surface ectoderm thickens and form lens placode. The lens placode invaginates towards cup. The placode changes to lens vesicle. It separates from surface ectoderm to form lens. The surface ectoderm folds and these folds first meet and then separates to form lid and anterior chamber.