Dacryocystography was preformed in all patients before operation to confirm the obstructive sity and the size of lacrimal sac.

术前了解囊的大小和阻塞的部位，择最佳手术适应证。

To illustrate the value of digital subtraction dacryocystography in the diagnosis of lacrimal duct obstruction.

评价数字减术在临床检查阻塞中的应用价值。