What is the most common cause of epiphora in newborn?

Congenital nasolacrimal duct obstruction is the most common cause of epiphora in newborn. It is most commonly caused by the failure of canalization of the valve of Hasner. Symptoms usually sta after 3 weeks of age with epiphora, matting of lashes and discharge. Conservative management with topical antibiotics and lacrimal sac massage is done in patients upto age of 9-12months. Initial probing is done when child presents beyond the age of 9-12 months or in case of failure of 3 months of conservative therapy. Ref: Clinical Ophthalmology edited by Sandeep Saxena page 757.