MAR 11, 2013
This article considers the term "functional block," which refers to the concept of lacrimal drainage dysfunction in the presence of anatomical patency. The authors conclude that this may be a confusing term for the condition of a likely heterogeneous group of patients. They suggest the term "functional epiphora" - with "no delay" or with "pre-or post-sac?? delay" - as a substitute.
The authors reviewed the clinical features, investigative findings and treatment options in patients with functional block. They found that if there is epiphora when all other causes have been excluded and there is no objective evidence of delayed outflow or a stenotic system, then the term "functional epiphora with no delay" seems appropriate. However, if clinical assessment and dacryocystography indicate a patent system with delay, then these patients should be classified depending on the level of outflow delay as either "functional epiphora with pre-sac delay," or "functional epiphora with post-sac delay." Finally, if dacryocystography indicates a stenotic system but patency on syringing, these patients should be distinguished from those with functional epiphora and classified as having nasolacrimal duct stenosis.
They write that this distinction is valid as treatment outcomes could differ between the groups, and this can only be determined by future studies utilizing comparable diagnostic criteria. However, they also acknowledge that these criteria are a crude attempt to subclassify this group of patients, and there is still no standardization for the investigations used.
They conclude that there is a need to standardize the interpretation of dacryocystography and for better normative data to examine the correlation between frequently used clinical tests and imaging.