Perspective: what does the term functional mean in the context of epiphora?

The term 'functional block' is used to encompass the concept of lacrimal drainage dysfunction in the presence of anatomical patency. There is significant variability in the nomenclature, clinical and investigative criteria used in the literature to define this entity. This has led to confusion and lack of comparability of studies looking at this group. The clinical features, investigative findings and treatment options in this group of patients are described. In addition, the need to differentiate between nasolacrimal stenosis and 'functional block' is emphasized, as evidence suggest patients with nasolacrimal duct stenosis have better outcomes with dacryocystorhinostomy. To better define the disease entity and enable comparability of future studies, it was proposed that this entity be replaced by the term functional epiphora with no delay, pre- or post-sac delay.