[2] Excessive tearing is the most common complaint of patients with nasolacrimal duct obstruction, followed by acute or chronic infections.

Although the inciting event in this process is unknown, clinicopathologic study suggests that compression of the lumen of the nasolacrimal duct is caused by inflammatory infiltrates and edema.

[citation needed] Dacryoliths or cast formation, within the lacrimal sac can also produce obstruction of the nasolacrimal duct.

Granulomatous disease, including sarcoidosis, granulomatosis with polyangiitis, and midline granuloma, may also lead to nasolacrimal duct obstruction.

Bloody punctual discharge or lacrimal sac distension above the medial canthal tendon is also highly suggestive of neoplasm.

[4] Around 6% of infants have congenital nasolacrimal duct obstruction, or dacryostenosis, usually experiencing a persistent watery eye even when not crying.

Nasolacrimal duct probing may be performed in the office setting (usually from 4 to 8 months of age) or under general anesthesia in an operating room for older patients.

The dye disappearance test is useful for assessing the presence or absence of adequate lacrimal outflow, especially in unilateral cases.

Some clinicians believe that partial stenosis of the nasolacrimal duct with symptomatic epiphora sometimes responds to surgical intubation of the entire lacrimal drainage system.

Surgical indications include recurrent dacryocystitis, chronic mucoid reflux, painful distension of the lacrimal sac, and bothersome epiphora.