Functional Obstructions of the Lacrimal System

Abstract

Functional obstructions of lacrimal drainage systems are an underdiagnosed entity. Epiphora in the presence of a patent lacrimal pathway and absence of alternative etiology could be the simplest description. Nomenclature has been confusing since functional issues of the lacrimal system have been poorly defined. Terms used include functional block, physiologic dysfunction, and functional acquired epiphora; however, the most common terminology used is functional nasolacrimal duct obstruction (FNLDO) [1–5]. Few authors have defined FNLDO to also include partial obstructions [5] but would be misleading since there is an anatomical issue rather than a functional one. Functional epiphora can be an alternate and probably a better term [1]. It is of utmost importance to rule out other causes of epiphora before labeling a case as functional. Functional issues can be of the upper or lower lacrimal system. Altered outflow dynamics without anatomical narrowing in the upper system is known to occur in older patients (mean age 57–64 years) with a high incidence of bilaterality (86 %) [6, 7]. These findings in upper system dysfunctions supports the theory of decreasing efficiency of the lacrimal pump secondary to weakening of the orbicularis oculi with increasing age as suggested by Jones in 1957 [8] and later supported by Worst in 1971 [9]. In addition, the lower system dysfunctions also occur more frequently in younger patients. This chapter aims to describe the clinical examinations, investigations, management, and outcomes of functional epiphora.