3 Embryology / Pathology
Optic vesicle
anterolateral outpouching of primitive brain stem; evaginates on day 25 and becomes the globe
Optic cup (Figure 3.2)
develops embryologically as an anterolateral evagination of the forebrain
Embryonic fissure
on undersurface of optic cups; closes on day 33 allowing pressurization of globe
Hyaloid artery (Figure 3-3)
enters through embryonic fissure and forms vasa hyaloidea propria (blood supply to primary vitreous)
Primitive epithelial papillae
Vitreous
produced by lens, retina, and walls of hyaloid artery; contains mesenchymal cells
Retina
Cornea
Lens
at 27 days, surface ectoderm adjacent to optic vesicle enlarges to form lens placode (lens plate)
Iris
rim of optic cup grows around lens and forms iris
Ciliary body (CB)
formation begins in 3rd month; fold in optic cup becomes epithelial layers of ciliary processes
Nasolacrimal system
at 6 weeks, surface ectoderm is buried in mesoderm, between maxillary and lateral nasal processes