Normal value of lacrimal duct irrigation

Insert the needle vertically into the lacrimal punctum to a depth of about 1.5 ~ 2.0 mm, and then rotate it 90. Point the needle to the nose, that is, the long uranium of the needle is parallel to the dangerous edge. The tip of the stool needle advances slowly along the lacrimal canaliculus. If there is no resistance, it can advance 5~6mm. Push the liquid into the tube with even and appropriate force. When washing, if the resistance is large, there is countercurrent or outflow from another lacrimal canaliculus, suggesting lacrimal duct obstruction. Different parts of lacrimal passage block the countercurrent direction of liquid. Pay attention to the depth when inserting the needle, so as not to damage the mucosa.