Vasculature, cornea, lens, iris, ciliary body, retina, sclera, eyelids, orbit, and extraocular muscles: later development and clinical notes

Notes

5-4 3rd gestational month → All corneal layers present except Bowman’s (appears during fourth month) VITREOUS  Primary vitreous made up of both mesenchymal and ectodermal origin  Formed by 8 weeks  Made of fibrils from developing lens (lens vesicle) and developing retina (optic cup)  Mesodermal cells migrate into primary vitreous & condense to form the endothelial linings of the hyaloid vasculature VITREOUS  Secondary vitreous formed by the 4th month  Secreted from the surface of the retina (neuroectoderm)  Avascular  Composed of collagen, hyaluronate ground substance & primitive hyalocytes  Compresses primary vitreous inward  Encloses area with atrophying hyaloid vessels (Cloquet’s canal)  Tertiary Vitreous well formed by 7th month of gestation  Condensed fibrils of the anterior secondary vitreous elongate (neuroectoderm) & become the lens zonules (tertiary vitreous)  Secondary vitreous regresses leaving behind hyaloideocapsular ligament HYALOID ARTERY SYSTEM  Hyaloid Artery:  One branch produces a dense vascular network that fills the vitreous cavity & forms the posterior tunica vasculosa lentis  Surrounds the posterior lens capsule  Other branches follow the opt...