The pathogenesis of canalicular laceration.

Canalicular lacerations are seen commonly in ophthalmic practice, but the pathogenesis of canalicular lacerations has not been explored. The authors retrospectively reviewed 25 cases of canalicular laceration seen at their institutions. Only 4 patients (16%) had injuries attributable to direct trauma; the remaining 21 patients (84%) had diffuse trauma or trauma to the eyelid remote from the canaliculus. The authors postulate that, in many of their cases, canalicular "lacerations" resulted from indirect trauma, where the eyelid was ruptured when it was stretched acutely to the point of avulsion. Two experimental models were derived to test this hypothesis. The results suggest that the canalicular portion of the eyelid is a particularly vulnerable location, and that injuries morphologically similar to canalicular "lacerations" occur predictably if the eyelid is traumatized indirectly or diffusely to the point of rupture.