Vitreous hemorrhage from the persistent hyaloid artery

The embryonic hyaloid system appears at the fifth week of gestation and com pletes the tunica vasculosa lentis by reaching the lens. Afterwards, other vascular structures take over the functions of the hyaloid vascular system and it starts to regress, Under normal conditions, regression of the embryo nic vascular system is complete at term or shortly after birth, Persistence of the hyaloid vascular system might be seen in the form of a Mittendorf's dot, Bergmeister's papilla, or persistent hyaloid artery, The persistent h yaloid artery is usually in the form of a thin cord, and active blood flow in the hyaloid artery during the postpartum period is rare.(1) Vitreous hem orrhage from the persistent hyaloid artery is very rare, and it has only be en documented in a few cases in the literature.(2-4) In this report, vitreo us hemorrhage from the loose end of a partially regressed hyaloid artery is presented, and possible factors in the pathogenesis of hemorrhage are disc ussed.