Acquired nasolacrimal duct obstruction.

Acquired nasolacrimal duct obstruction is a common problem. Although tearing is the usual complaint, the clinical presentation can range from a patient having no symptoms to one with a life-threatening infection. Despite many studies providing useful clues, the exact pathophysiology of the obstructive process is incompletely understood. The clinician must be able to accurately make the diagnosis, which is often a clinical one, because many treatments with excellent success are available.