This instrument was used in a process called lacrimal syringing, the purpose of which is to check the naso-lacrimal passage for any blockage, or to flush out debris in the case of a lacrimal passage infection. This technique is also suitable for administering antibiotics and for introducing dye in preparation for taking X-ray images.

The Nettleship dilator is gently inserted into the lower punctum (tear duct), following the direction of the lower canaliculus, rotated gently a few times and then withdrawn in order to allow the insertion of a syringe to flush out the lacrimal passage (to clear blockages from the tear duct).