OVERVIEW
Ocular discharge is a common sign of eye disease. Abnormal discharge may develop suddenly or gradually. The discharge may be watery, mucoid (gray, ropy), mucopurulent (yellow-green, thick) or bloody. In general, the more discharge present, the more serious the disease.

CAUSES
Obstruction of tear drainage due to abnormal tear ducts or tear duct openings


Excessive production of tears by the tear glands from irritation or inflammation of the surface structures of the eye, or from pain in or around the eye. Examples include:


Keratitis (inflammation of the cornea)
Conjunctivitis
Blepharitis (inflammation of eyelids)
Defects or abnormalities in the eyelids
Corneal ulcers
Glaucoma
Lens luxation (displacement)
Uveitis (inflammation of the iris and blood vessel layers within the eye)
Trauma
Keratoconjunctivitis sicca or dry eye syndrome


Infection on the surface of the eye, or in association with generalized infections or illness
DIAGNOSIS
Certain diagnostic tests are essential to determine the precise cause for the ocular discharge, including:


Complete ophthalmic examination of the eyelids, cornea, conjunctiva and the front and back chambers of the eye


Schirmer tear test


Fluorescein and possible rose bengal staining of the cornea


Tonometry to measure the pressure within the eye

Additional diagnostic tests are required to diagnose some causes of ocular discharge. These may include:


Complete physical examination


Cytology or complete cell analysis of samples collected from the eyelid margins, cornea and conjunctiva


Flushing of the openings where the tears drain away from the eye to ensure they are patent (open)


Culture of discharge from the eye to determine the presence of bacterial infections


Complete blood count (CBC) and serum tests to identify the presence of any related problems


Possibly skull X-rays to determine the presence of a problem in the space behind the eye or in the sinuses
Possibly specialized imaging tests such as dacryocystorhinography (an X-ray study of the tear drainage system), computed tomography (CT) scan, and magnetic resonance imaging (MRI)
TREATMENT
Successful therapy relies on obtaining an accurate diagnosis. Do NOT use human over-the-counter eye drops.
HOME CARE
Gently clean away any eye discharge with a warm moist cloth as needed until the cause of the problem is identified. Do not allow your pet to rub or self-traumatize the eyes.

Do not delay in bringing your pet to the hospital for examination as some causes of excessive ocular discharge are potentially vision threatening and require immediate medical attention. Do not administer human prescription eye medicine or even over-the-counter medicines such as Visine® or other topical solutions intended to reduce eye redness to your pet. The underlying cause for the problem must be properly addressed.

As a temporary measure, the eyes may be flushed or the eyelids cleansed with sterile saline contact lens solution.

INFORMATION IN-DEPTH
It is important to understand that any source of ocular irritation or pain can cause ocular discharge. Abnormal ocular discharge is not diagnostic of any one disease or disorder. In the simplest sense, ocular discharge represents the response of the eye to an irritation or injury or an inability to drain tears or secretions properly. The exact cause can only be determined by a careful examination and appropriate diagnostic tests.

Observe your pet for any change in eye discharge. A minor amount of eye discharge is normal; however, any change from what is normal for your pet may be significant and is often quite obvious.

Decisive therapy of ocular discharge depends on identifying the exact cause of the symptom. There are numerous possible inciting causes for ocular discharge. It is essential to distinguish a specific cause to provide the appropriate therapy.

CAUSES
Among the potential causes of ocular discharge are the following disorders:


Cilia (eyelash) disorders such as distichiasis, which are eyelashes that grow along the edge of the eyelids and rub on the cornea, and trichiasis, which are lashes on the outer eyelids or face that are long enough to rub the eye


Conformational eyelid defects such as inward rolling of the eyelids (entropion), and congenital absence of a portion of the upper eyelid (eyelid agenesis).


Inflammation of the eyelids (blepharitis) or inflammation of the Meibomian glands within the eyelid margins from an immune-mediated, or a bacterial, fungal or parasitic infection


Prolapse (protrusion) of the tear gland of the third eyelid, often referred to as “cherry eye” and rare in the cat


Tumors of the external eyelids and third eyelid


Deformities or wounds of the third eyelid


Inflammation, infection or foreign material within the tear duct drainage system (dacryocystitis) obstructing the drainage of tears away from the eye


Keratoconjunctivitis sicca (dry eye syndrome)


All forms of conjunctivitis


Traumatic scratches, lacerations or ulcerations of the cornea, conjunctiva and eyelids


Trauma to the nose, palate or bones of the face around the eye


Certain forms of inflammation of the cornea (keratitis)


Anterior uveitis, which is inflammation of the iris and surrounding tissues in the front portion of the eye


Glaucoma, which is sustained elevation of pressure within the eye


Lens luxation or dislocation into the front chamber of the eye


Inflammation, infection, trauma, or tumor development in the soft tissues around the eye


Infection and abscessation of the roots of the back upper teeth

VETERINARY CARE IN-DEPTH

DIAGNOSIS IN-DEPTH
The following diagnostic tests may be recommended in diagnosing and treating your pet’s ocular disease:


Complete medical history and physical examination


Complete ophthalmic examination including a Schirmer tear test to determine if tear production is normal, elevated or reduced; fluorescein staining of the cornea to detect surface defects, ulcers and erosions; tonometry to measure the pressure within the eye;, and examination of the interior of the eye under magnification. Your veterinarian may refer your cat to a veterinary ophthalmologist for detailed evaluation of the eye using specialized instrumentation.


Cytology (cell analysis) of samples collected from gland openings in the eyelid margins or from the cornea and conjunctiva


Flushing of saline through the tear ducts to ensure they are open


Complete blood count (CBC) and serum tests to identify any related problems.

Initial test results and/or lack of response to initial treatments may necessitate further testing including:


Culture of material from infected areas


Polymerase chain reaction (PCR) and immunofluorescent antibody (IFA) tests on samples collected from the conjunctiva and cornea to detect certain viral infections such as herpesvirus and calicivirus


Skin cell scrapings from the eyelid or eyelid margin to help determine the presence of parasitic infection, fungal infection, cancerous disease or bacterial infection


A fine-needle aspirate (FNA) of any solitary mass/tumor around the eye


Serology testing for feline leukemia virus, feline immunodeficiency virus, feline infectious peritonitis virus, toxoplasmosis and cryptococcosis


Biopsy (tissue sample)of abnormal deep tissue around the eye


Ultrasonography of the eye and surrounding soft tissues


Skull X-rays to identify fractures, diseases of the sinuses, and bony tumors of the head


Dacryocystorhinography, a specialized X-ray study of the tear duct drainage system (rarely performed in the cat)


Computed tomography (CT) scan or magnetic resonance imaging (MRI) to identify problems within the eye, around the eye, within the nose and sinuses, the bones of the face or the brain.