Initiation of corneal differentiation prior to cornea-lens association.
D000818:Animals; D002454:Cell Differentiation; D002642:Chick Embryo; D003315:Cornea / Q000196:embryology*; D004848:Epithelium; D007908:Lens, Crystalline / Q000502:physiology*; D008854:Microscopy, Electron; D013997:Time Factors