Canine Nasolacrimal Duct and Lacrimal Secretory Systems: Diseases and Surgery

Abstract

The nasolacrimal duct system of the dog is similar to that of most domestic animals. It is a thin-walled conduit that drains the tear film from the eye into the nasal passages. This chapter reviews the embryology, anatomy, physiology, and diagnostic procedures, as well as the clinical manifestations for both congenital, developmental, and acquired diseases, and their appropriate medical and surgical management. The “head-water” of the tear system is the lacrimal glands, located dorsolateral of the globe and within the nictitating membrane. Tear abnormalities are among the most common causes of canine ocular surface disease. Cysts involving lacrimal tissue, though uncommon, have been reported and may originate from either the orbital or the nictitans glands. Although lacrimal neoplasms are also uncommon in the dog, primary adenomas and adenocarcinomas of the orbital and nictitans glands have been reported. These tumors tend to be locally invasive and have a guarded prognosis.