The system begins at the lacrimal puncta, located on the palpebral conjunctiva near the medial canthus. The cat possesses both superior (upper) and inferior (lower) puncta, though the inferior punctum is clinically more significant for drainage. From the puncta, the canaliculi converge to form the lacrimal sac, which sits within the bony lacrimal fossa of the lacrimal bone.
Epiphora is the overflow of tears onto the face. In cats, this is often characterized by a reddish-brown staining of the periocular fur due to porphyrins in the tears. While epiphora can result from overproduction (reflex tearing due to irritation), NLD obstruction is a primary differential. Obstruction may be functional (pump failure) or anatomical.
A primary cause, as the virus can cause scarring that permanently narrows or closes the duct. nasolacrimal duct cat
The nasolacrimal system serves as the drainage conduit for the preocular tear film, maintaining ocular surface homeostasis. In the domestic cat, dysfunction of this system is a common presenting complaint in veterinary ophthalmology, manifesting primarily as epiphora (excessive tearing) or mucopurulent ocular discharge. Unlike the brachycephalic canine breeds, where skull conformation significantly alters nasolacrimal dynamics, the feline system presents unique anatomical nuances, particularly regarding the termination of the duct and its relationship with the nasal planum. Understanding the anatomy and potential pathologies of the feline NLD is essential for accurate diagnosis and effective management of ocular surface disease.
Brachycephalic (flat-faced) breeds like Persians and Himalayans often have kinked or compressed ducts due to their facial structure. The system begins at the lacrimal puncta, located
Obstructions can be present from birth or develop later in life due to health issues:
By understanding the importance of the nasolacrimal duct and being aware of potential issues, you can help keep your feline friend's eyes healthy and happy! Epiphora is the overflow of tears onto the face
In the cat, the viscosity of the tear film and the diameter of the puncta play significant roles in drainage efficiency. The termination of the duct within the ventral nasal meatus means that normal tear drainage often goes unnoticed by owners, as it does not typically cause moisture at the external nostril unless drainage is excessive.
The system begins at the , tiny openings on the inner edges of the eyelids. Tears enter these slits, travel through the canaliculi into the lacrimal sac, and finally move through the nasolacrimal duct itself—a narrow tube that snakes through the maxillary bone. Interestingly, in cats, this duct is closely situated to the roots of the upper canine teeth, meaning dental issues can sometimes directly impact tear drainage. When the System Fails: Epiphora
Tears can cause hair to clump, which may painfully rub against the eye and cause scratches.
The nasolacrimal duct (NLD) is a critical component of the feline ocular adnexa, responsible for the drainage of tears from the ocular surface into the nasal cavity. While often overlooked in routine examinations, the NLD is frequently implicated in cases of epiphora and recurrent conjunctivitis in domestic cats ( Felis catus ). This paper reviews the anatomical trajectory of the feline NLD, contrasts its physiology with other domestic species, and discusses the pathophysiology of common clinical conditions such as dacryocystitis and imperforate puncta. Furthermore, current diagnostic approaches and therapeutic interventions, including flushing techniques and stenting, are evaluated.