Overview of Feline Epiphora (Excessive Tearing)
Epiphora is an abnormal overflow of tears down the face that results from either obstruction of tear drainage through the nasolacrimal (tear duct) system or overproduction of tears that overwhelms the cat’s normal drainage system. The overproduction of tears is most often a reflex, activated to expel irritating material from the surface of the eye or when significant irritation develops inside the eye. Although uncommon, epiphora may also result from overactive lacrimal (tear) glands and be unassociated with any source of irritation.
Normal cats may occasionally have minor tear overflow or minor eye discharge. However, excessive, chronic or recurrent bouts of epiphora suggest a problem may be present.
Tears are continuously produced on the eye in most cats. With each blink of the eyelids, tears are pushed along the outer aspect of the eyelids towards the nose. A small hole called a puncta is present in both the upper and lower eyelid very close to the where the lids meet near the nose. Tears normally flow down these two drainage holes into a central collecting sac (lacrimal sac) that sits just under the skin below the eye. From this sac, a small tube or duct (nasolacrimal duct) carries the tears into the nose. In some cats the duct opens just inside the nostril. In other cats, the duct opens further back in the nose. The tears also help keep the nose and nostril moist.
While tears are typically colorless, they can dry to a dark red-brown-black crust, especially in the cat. Chronic tearing can also result in a brown to rust-colored staining of the hair around the eyes and face of cats. This is believed to be due to porphyrins or other pigment-like substances present in the tears.
Tears that spill over onto the face can also be irritating to the skin of the face. Moisture and bacterial build-up in that area aggravates this irritation.
Causes of Excessive Tearing in Cats
Epiphora can be caused by numerous conditions. Some common causes of tear flow obstruction include:
Inefficient drainage of tears from partial closure of the drainage openings, increased kinking of the drainage duct in the nose, or wicking of tears onto hairs present in the crease where the eyelids meet. This condition is most common in the flat faced, long-haired breeds of cats, particularly the Persian and Himalayan breeds.
Abnormally small tear duct openings
Inflammation within or nearby the tear duct system
Tear duct scarring after severe conjunctivitis
A foreign body lodged within the tear duct (rare in cats)
Epiphora can also result when tear production increases due to irritation of the eye or stimulation of the tear glands. Common causes of epiphora in this group include:
Hair rubbing on the eye from deformities of the eyelids, eyelashes growing in an abnormal location (distichiasis), or hair growing in a direction that bring it close to the eye (trichiasis)
Inflammation of the eyelids themselves (blepharitis)
Keratitis or inflammation of the cornea
Corneal ulcerations, abrasions, scratches, wounds
Foreign body on the surface of the eye or exposure to irritants, such as smoke, chemicals, and soaps
Anterior uveitis, or inflammation of the iris and ciliary body
Irritation or stimulation of tear glands from topical eye medications
Irritation from suture material around the eye from a recent surgery
Infection or irritation around or under the eye or within the eye socket (orbit)
Tearing with eating, which is a rare form of stimulation of the tear glands
Some of the above disorders cause both obstruction of tear flow and stimulation of excessive tear production.
What to Watch For
Watery discharge from one or both eyes
Possible tear staining on face below the eye, near the nose
Accumulation of dried discharge on the edges of the eyelids
Ulceration and irritation of the skin below the eye, near the nose
Rubbing of the eyes or face
Redness of the conjunctiva
Dramatic color change or cloudiness to the surface or within the eye
Possible pain with increased blinking or squinting
Possible swelling of the eyelids or face around the eyelids
Possible reduction or loss of sight
Possible change in size of the pupil or eyeball
Diagnosis of Epiphora in Cats
Veterinary care often includes diagnostic tests to determine what is causing the epiphora or ocular discharge. Epiphora is initially classified into one of three categories:
Obstruction of tear flow through the nasolacrimal duct system
Reflex stimulation of tears due to ocular irritation
Overproduction of tears by the lacrimal glands (least common)
Once a specific diagnosis has been established, appropriate treatment can be instituted.
There are several potential diagnostic tests that help delineate the cause of the epiphora. Your cat may be referred to a veterinary ophthalmologist for further evaluation and completion of some of these tests, which may include:
Complete ophthalmic examination including magnified examination of the eyelids, tear drainage holes (puncta), conjunctiva, cornea and front chamber of the eye
Schirmer tear test to determine if tear production is below normal, normal or excessive in quantity
Fluorescein and possibly Rose Bengal staining of the cornea to assess for the presence of ulcers, lacerations or scratches
Tonometry to measure the pressure within the eye to evaluate for the presence of glaucoma
Flushing of the tear duct system with saline to determine if it is open all the way to the nose
Dacryocystorhinography is the flushing of the entire tear duct system with a contrast agent that is visible on X-rays. It is a special X-ray technique that helps outline the tear drainage system from the corner of the eye all the way to the nose. This X-ray study may be done when congenital absence of part or all of the nasolacrimal system is suspected, or when compression, cystic dilatation, scarring or obstruction of the system is suspected. It is performed under general anesthesia.