The feline nasolacrimal system begins at the superior and inferior puncta, small openings located on the upper and lower eyelids at the medial canthus (inner corner of the eye). These puncta lead into the canaliculi, which converge to form the lacrimal sac. From the lacrimal sac, the nasolacrimal duct descends through the bony lacrimal canal and empties into the nasal vestibule. Unlike in dogs, the feline duct typically has a narrower lumen and a more tortuous course, making it potentially more susceptible to complete obstruction. The distal opening (nasal punctum) is located approximately 2–5 mm inside the nostril on the floor of the nasal vestibule.
Nasolacrimal duct obstruction (NLDO), commonly referred to as a blocked tear duct, is a relatively common ophthalmic condition in domestic cats. The nasolacrimal duct system is responsible for draining tears from the ocular surface into the nasal cavity. When this system becomes obstructed, epiphora (excessive tearing) results, often leading to periocular dermatitis, cosmetic concerns, and in some cases, secondary infection. This paper reviews the anatomy of the feline nasolacrimal system, the various etiologies of obstruction (congenital and acquired), diagnostic techniques including the fluorescein dye transit test and dacryocystorhinography, and current medical and surgical management strategies. A focus is placed on breed predispositions, particularly in brachycephalic cats, and the importance of ruling out underlying causes such as neoplasia or chronic rhinitis. cat blocked tear duct
Complete slit-lamp biomicroscopy should rule out corneal disease (ulcers, keratitis), uveitis, or glaucoma as causes of reflex tearing. The feline nasolacrimal system begins at the superior
A 4-year-old Persian cat presented with chronic left-sided brownish ocular discharge. Schirmer tear test and corneal staining were normal. Fluorescein dye failed to reach the left nostril after 15 minutes. Nasolacrimal flushing with saline encountered mild resistance, followed by reflux of mucoid debris. No foreign body or mass was seen on skull CT. The cat was diagnosed with chronic idiopathic partial obstruction. Treatment consisted of weekly ductal flushing under sedation and topical antibiotic-steroid ointment for 4 weeks, resulting in decreased discharge. The owner was advised of possible recurrence. Unlike in dogs, the feline duct typically has
Feline nasolacrimal duct obstruction is a manageable yet often chronic condition that requires a systematic diagnostic approach. The fluorescein dye transit test and ductal flushing remain essential diagnostic and therapeutic tools. Clinicians should differentiate congenital (breed-associated) from acquired (inflammatory, neoplastic, traumatic) causes to guide prognosis and treatment. While medical management suffices for mild cases, surgical bypass is available for severe, refractory obstructions. Further research into the role of viral rhinitis in chronic feline NLDO would improve long-term management strategies.
Congenital NLDO is most frequently observed in brachycephalic breeds such as Persians, Himalayans, and Exotic Shorthairs. Due to their flattened facial conformation, the nasolacrimal duct may be compressed, narrowed, or fail to develop a patent distal opening (functional imperforate punctum). In some kittens, the puncta may be anatomically absent (atresia).