Hyaloid artery patency in neonatal beagles.

The patency of the hyaloid artery in neonatal Beagles was evaluated after liquid latex perfusion. As early as postpartum day 5, some pups had closure of the most distal branches of the vessels of the posterior lens tunica, but in these, many larger branches were open. Other pups at postpartum days 5 and 6 had substantially all of the blood vessels of the posterior tunica vasculosa lentis open. Few tunica vessels were patent in any pups beyond day 13, and none was patent after day 17. Persistent hyaloid remnants at the optic disk were evident in 3 of 16 pups 17 to 28 days old, but absent in the others.