Obstruction of nasolacrimal drainage apparatus results in epiphora and can be primary or secondary, congenital or acquired. Obstruction can occur at canalicular, lacrimal saccular, or nasolacrimal ductal (post-saccular) levels.
Causes of obstruction
Congenital obstruction
- persistence of the membrane at the valve of Hasner, resulting in complete nasolacrimal duct obstruction and dacryocystitis
Acquired obstruction
- primary
- secondary
- trauma: facial fractures
- surgery
- inflammatory diseases e.g. sarcoidosis, granulomatosis with polyangiitis
- neoplasms
- ethmoid mucoceles
- obstruction of the canaliculi includes:
- infections
- skin burns
- drugs for glaucoma
- chemotherapeutic agents e.g. fluorouracil