Evaluation of lacrimal tear drainage mechanism using dynamic fluoroscopic dacryocystography.

Purpose: To evaluate the dynamic change of the canaliculus and the lacrimal sac during blinking using fluoroscopic dacryocystography.

Methods: Sixteen patients presenting with unilateral epiphora were enrolled in the study. Fluoroscopic dacryocystography was performed in both eyes, and sequential images of the lacrimal drainage system were acquired during blinking. On examination of the contralateral asymptomatic side, the length of the lower canaliculus and the width of the superior and inferior portions of the lacrimal sac were measured and compared between eyelid closure and opening.

Results: The length of the lower canaliculus decreased with eyelid closure in 13 of 16 patients, and the change was statistically significant (p = 0.006, Wilcoxon signed rank test). The width of the superior portion of the lacrimal sac increased with eyelid closure (p = 0.033), but the width of the inferior part did not change significantly (p = 0.679).

Conclusions: With eyelid closure, the canalicular system contracts, and the superior portion of the lacrimal sac dilates; these may be important parts of the active lacrimal pump mechanism. These findings suggested that the canalicular system and the superior portion of the lacrimal sac play key roles in active tear drainage pump.