Idiopathic acquired lacrimal drainage obstruction.

THERE are two basic types of idiopathic acquired obstruction of the lacrimal drainage system.Canaliculus Obstruction.-Thisusually occurs close to the point of entry of the canaliculus into the lacrimal sac, either in the lower canaliculus itself or in the common canaliculus.Naso-lacrimal Duct Obstruction.-Thisusually occurs at the upper end of the duct where it becomes continuous with the lacrimal sac.