How successful is tear duct probing?

Tear duct probing is a procedure performed for diagnosis and treatment of tear duct obstructions (NLDO). In infants who are born with a congenital NLDO, the procedure itself opens the blockage by breaking through the membrane closing the duct. It is highly successful, with some studies stating resolution of symptoms in over 90 percent of patients. In cases where probing is unsuccessful, the congenital obstruction may have to be bypassed with a surgical procedure called a dacryocystorhinostomy (DCR). In adults, tear duct probing is done as a test to diagnose for NLDO rather than for relieving the blockage. In this case, a special surgical tool is placed into the tear duct and saline (salt water) is injected. If the patient feels the saline in the nose or throat, then the tear drainage system does not have a complete blockage. If the patient does not feel the saline, then there is an obstruction in the tear duct that would need to be bypassed by a surgical procedure such as a DCR. Occasionally, mucus plugs can also temporarily block the tear duct. In this case, flushing with saline can push the mucus plug along and reopen the tear duct.