ABSTRACT
Between weeks 4 and 5 the lentoretinal space becomes filled with fibrils, mesenchymal cells and vascular channels. These elements constitute the primary vitreous. The mesenchymal cells and vascular channels derive from the hyaloid artery, which enters the optic cup through the choroidal fissure. The hyaloid artery gives rise to a series of small capillaries that anastomose with choroidal and long ciliary arteries to form a vascular capsule, the tunica vasculosa lentis, providing the rich nutrient supply necessary for the rapid growth of the lens during development.
