Development of the eye

The eyes start to develop at around day 22 of embryonic life. They first appear like outpocketings of the forebrain, called optic vesicles. They, therefore, have a neuroectodermal origin. These vesicles invaginate and develop double-walled optic cups, which later generate various parts of the eye. Cells that form various eye structures have different origins. The retina, optic nerve, and ciliary body have a neuroectodermal origin, whereas the lens comes from the ectoderm, and the choroid and cornea come from the mesenchymal.