To investigate the different types of anatomical connection between the lacrimal sac and the canaliculi using digital subtraction dacryocystography (DCG) in Koreans.

The authors of the present study performed digital subtraction DCG in Korean patients who presented with epiphora from January 2010 until December 2010. The 248 patients (496 eyes) who achieved a satisfactory DCG image were classified as follows: 1) type I: visible common canaliculus (CC), 2) type II: no visible CC and the canaliculi entering the sac at the point where they meet on the sac wall (common opening), 3) type III: no visible CC and common opening, and each canaliculus entering the sac from different points.

Out of a total of 496 eyes, CC was observed in 449 eyes (type I: 90.5%). In 41 eyes (8.3%), the CC was absent (type II), but the upper and lower canaliculi joined at the wall of the lacrimal sac. In 6 eyes (1.2%), the upper and lower canaliculi entered the sac separately (type III). Eighteen patients (7.3%) showed different types of lacrimal drainage system between the 2 eyes.

The CC may not exist in all patients, and the type of anatomical connection between the lacrimal sac and the canaliculi may be different between the eyes in the same individuals. Although such patients comprise a minority, anatomical knowledge of the lacrimal drainage system could be helpful to assess and manage patients with lacrimal drainage disorder.