Dacryoendoscopy as a frontier technology for lacrimal drainage disorders

Dacryocystorhinostomy (DCR) for adult patients with acquired nasolacrimal duct obstruction can be performed via 2 approaches: an external nasal approach from the skin and an internal nasal approach from the nasal cavity. Both techniques have a history of over 100 years and are the gold standard approaches for the treatment of nasolacrimal duct obstructions. Alternatively, researchers have also attempted lacrimal passage reconstruction using various stents to restore the patency of the lacrimal passage, with nunchaku-type silicone tubes showing good surgical results according to several published reports. However, in cases in which the procedure required blind manipulation, the results were largely dependent on the surgeon's skill. Under such circumstances, the dacryoendoscope was introduced at the beginning of this century and is currently widely used. In other fields, especially in gastroenterology, the introduction of gastrointestinal endoscopes that enable observation and treatment of lesions under direct observation has dramatically improved the treatment of gastrointestinal disorders. Considering that the dacryoendoscope has become standardized over the past 20 years since its introduction, this review summarizes the current status of lacrimal passage treatment using the dacryoendoscope.