STENOSIS OF THE LACHRYMO-NASAL DUCT.
Obliteration of the lachrymal duct may occur from stricture of the canal, the result of wounds or other irritants: from pressure by the inflamed mucosa in nasal catarrh or strangles: from polypus or osseous tumor in the nose: from actinomycosis or other disease of the bones.
The one manifest symptom is the escape of the tears on to the face. To complete the diagnosis, injection of one punctum will cause distension of the lachrymal sac.
Treatment. This may be attempted by bougies. In the horse a small sound, metallic or whalebone bougie, thoroughly sterilized and smeared with aseptic vaseline, or oil, is inserted from the nasal opening and carefully passed on into the sac. In the dog the nasal opening cannot be reached and the bougie must be passed by the puncta and lachrymal sac. To secure the requisite dilation, it is usually necessary to probe the passage daily, using a larger probe when the first passes easily, until the canal has been sufficiently dilated.
A second resort is to distend the canal by a liquid injection thrown into the nasal opening. This will succeed when the obstruction is only caused by concretions in the canal.
A somewhat similar resort is the insufflation of the duct by means of a finely pointed tube inserted from below into the nasal orifice of the duct.
Still another method is to make a new opening for the escape of the tears into the nose. When the stenosis is at or near the nasal opening of the duct, an artificial opening is easily made and usually satisfactory. Under anæsthesia, a sterilized silver probe is passed through the upper punctum, the sac and canal. When it meets definite obstruction its position is ascertained inside the nose, and an incision is made so as to allow its escape. The constant escape of tears tends to prevent it from closing up again, but it is well to examine into this until it has thoroughly healed. A silk thread worn in the duct and held in place by a copper or aluminum ring on each end may be resorted to.
Attempts have been made to establish a new outlet by boring through the lachrymal bone into the nose, but without a permanent success. It has also been advised to obliterate the lachrymal ducts and sac, on the one hand and to excise the lachrymal gland on the other, but the proposed cure is worse than the disease.