Unblocking the tear duct is called dacryocystorhinostomy (DCR) and is usually carried out under local anaesthetic with sedation, sometimes under general anaesthetic.
The surgery creates a new pathway between the lacrimal sac and the inside of the nose by removing thin bone between them. Silicone tubes are temporarily inserted in most cases to keep the new tear duct open while healing takes place. A DCR has traditionally been performed through a small skin incision at the side of the nose (external DCR).
DCR removes the risk of an infection in the tear sac, known as dacryocystitis, This can develop when tears stagnate in the tear sac because of a blockage of the nasolacrimal duct. It is a painful condition that requires antibiotic tablets and sometimes injections and drainage of the tear sac. After DCR surgery, tears can no longer stagnate so the risk of infection of the sac is removed.