The lacrimal drainage system: pressure changes in the canaliculus.

In order for tears to be removed from the eye, pressure gradients must be created in the ducts which lead to the nose. Blinking is only one of a number of mechanisms potentially capable of doing this. Pressure in the lacrimal canaliculus was recorded during voluntary blinks, tight squeezing of the lids, eye movements, and pressure changes in the nose. The results show that all of these produce pressure changes in the canaliculus.