Dacryoendoscopy-assisted incision of Hasner’s valve under nasoendoscopy for membranous congenital nasolacrimal duct obstruction after probing failure: a retrospective study

摘要

CT-DCG of a membranous CNLDO patient. a. An axial image. b. A sagittal image. a and b. The contrast medium was blocked at the end of the nasolacrimal duct, showing the shape of the whole duct. The enlarged Hasner’s valve was shown by the red arrows