Exogenous ball valve in the lacrimal sac.

A young man presented with symptoms and findings of a chronic partial obstruction of the lacrimal sac outlet. A dacryocystogram revealed a BB in the lower portion of the lacrimal sac where this foreign body was functioning as a ball valve, impeding lacrimal drainage. Surgical removal of the BB and dacryocystorhinostomy were curative. Previously reported foreign bodies in the lacrimal sac have all been endogenous in origin. This is the first reported case of an exogenous foreign body in the lacrimal sac outlet. Exogenous sources of lacrimal sac foreign bodies should be considered in chronic dacryocystitis.