OBSTRUCTION OF THE LACHRYMAL PUNCTA. ATRESIA. INFLAMMATION.
Congenital atresia of these puncta has been recorded in foals, by Hollmann and obstruction as the result of inflammation, by Lafosse, Verjaus and Tyvaert, and of the entrance of the seeds of bromus by Stockfleth.
Apart from congenital atresia and impaction of foreign bodies the symptoms are those of conjunctivitis, with escape of tears over the face (epiphora). Injection of aseptic water into the lower puncta and its escape by the upper, and by the nasal orifice, will determine the patency or otherwise of the various channels.
Treatment consists in astringent collyria to check the inflammation, in the removal of any foreign body, in the dilation or slitting of the lachrymal canaliculi, and in case of complete atresia, in incising the lachrymal sac. Slitting of the canaliculi is accomplished by a small probe pointed bistuory (canaliculus knife). The lid is drawn away from the carnucle, and the probe point inserted at first downward, then inward and backward, and when it is well inside the sac the handle is brought to the vertical and the walls of the duct slit open.
In case of atresia Leblanc recommends to seize the inner canthus with rat tooth forceps so as to include the structures about the sac and to plunge the bistuory directly into the sac. Then by the aid of a whalebone staff he passes three silk threads through the duct and fixes them in place by attaching them to a copper ring at each end. This is retained in place and moved daily until the passage has been definitely healed and its permanency assured.