A delicate equilibrium between tear production and loss is controlled by the lacrimal system. Biological, environmental, and physical factors continuously infl uence this balance. Tear production in excess of loss directly causes tearing, whereas tear loss in excess of production stimulates refl exive tear production, which may also lead to epiphora [ 1 ]. Lacrimal outfl ow diseases are mainly related to obstruction, which could be congenital or acquired. Obstruction could derive or be complicated by infections, deriving from a primary nasolacrimal pathology or incidental to descending infl ammation from the eye or ascending infl ammation from the nose.
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