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Nasolacrimal Duct Obstruction and Epiphora

Background

Epiphora is defined as the overflow of tears. The clinical spectrum of epiphora ranges from the occasionally bothersome trickle to the chronically irritating overflow. Epiphora is caused by a disruption in the balance between tear production and tear drainage. The lacrimal drainage system is a continuous and complex membranous channel whose function is dependent on the interaction of anatomy and physiology.

When faced with a patient who complains of tearing, the first step is to determine whether the epiphora is caused by an increase in lacrimation or a decrease in tear drainage. Trichiasis, superficial foreign bodies, eyelid malpositions, diseases of the eyelid margins, tear deficiency or instability, and cranial nerve V irritation may cause an abnormal increase in tear production. In the absence of these conditions, an abnormality in tear drainage is the most likely cause.

Abnormalities of tear drainage may be subdivided further into functional and anatomical. Functional failure is related to poor lacrimal pump function, which may be due to a displaced punctum, eyelid laxity, weak orbicularis, or cranial nerve VII palsy. Anatomical obstruction may occur at any point along the lacrimal drainage pathway and may be congenital or acquired. Congenital obstructions tend to produce symptoms during the neonatal period and are the subject of another article, Nasolacrimal Duct, Congenital Anomalies.

Classification of nasolacrimal drainage obstruction

The 2 types of acquired nasolacrimal drainage obstructions (NLDO) are primary and secondary. In 1986, Linberg and McCormick coined the term primary acquired nasolacrimal duct obstruction (PANDO) to describe an entity of nasolacrimal duct obstruction caused by inflammation or fibrosis without any precipitating cause.
Bartley proposed an etiologic classification system for secondary acquired lacrimal drainage obstruction (SALDO) based on published cases.

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