NOT infrequently (following the successful probing of a congenitally blocked nasolacrimal duct in an infant), attempts to irrigate through the apparatus into the nasopharynx are unsuccessful. The irrigating solution backs up along the canaliculus into which the lacrimal cannula has been inserted, causing reflux to occur about the shaft of the cannula. Even when a punctum dilator is placed in the opposing lid punctum to increase the hydrostatic pressure within the system, reflux often persists because the cannula tip does not fit snugly into the punctum. In order to cope with this problem, a bevelled cannula has been devised (Fig 1), the tip of which extends approximately 3 mm beyond the tapered shoulder, permitting the instrument to fit snugly into the punctum, thus preventing reflux. The irrigating solution can be injected through the system under pressure while the opposing punctum is occluded with the punctum dilator. The use of
Tulevech CB. A New Canaliculus Irrigating Tip. Arch Ophthalmol. 1969;81(3):369. doi:10.1001/archopht.1969.00990010371014
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