Fig. 3

Nasal endoscopic images during operation. a. The endoscopic finding of the nasal cavity. The abnormal Hasner’s valve was covered by inferior turbinate. b. The inferior turbinate was pushed towards the nasal cavity to widen the surgical space. c. The end of NLD was thick and overdeveloped. d. A Crawford probe was inserted very gently into the distal end of the nasolacrimal duct and the probe and surrounding mucosa protruded shaped like a tent. e. The membrane at the distal end of the NLD was fully incised using a sickle knife; after that the pus and secretions rapidly flowed into the inferior duct. f. The surplus membrane in the distal end was separated and cut off using superfine mucosal scissors. g & h. Light from dacryoendoscope was used to identify the exact position of end of the NLD from the vision of nasal endoscopy. i. Previous probing left a very tiny hole (the arrow) at the mucosa of the abnormal Hasner’s valve but the lacrimal duct was not fully opened. j. Magnification of the image inside the black ring in Fig. 3i.