Remnants of the hyaloid vascular system (HP_0007968) can be described as follows. Persistence of the hyaloid artery, which is the embryonic artery that runs from the optic disc to the posterior lens capsule may persist; the site of attachment may form an opacity. The hyaloid artery is a branch of the ophthalmic artery, and usually regresses completely before birth. This features results from a failure of regression of the hyaloid vessel, which supplies the primary vitreous during embryogenesis and normally regresses in the third trimester of pregnancy, leading to a particular form of posterior cataract. Also known as: Congenital retinal septum, Persistent fetal vasculature, Persistent foetal vasculature, Persistent hyperplasia of primary vitreous, Persistent hyperplastic primary vitreous, Persistent hypertrophic primary vitreous, Persistent posterior fetal fibrovascular sheath of the lens, Persistent posterior foetal fibrovascular sheath of the lens.