Silicone Intubation Indications in External Dacryocystorhinostomy

External dacryocystorhinostomy (DCR) is the gold standard surgical technique for the treatment of nasolacrimal duct obstruction (1). Since its introduction by Gibbs in 1967, intubation with silicone tubes has been widely used in lacrimal duct surgery (2). However, effect of silicone intubation on patency of lacrimal system during external DCR in cases of primary nasolacrimal duct obstruction (NLDO), canalicular obstruction or in revision surgeries is still controversial.