Ocular discharge, often called “goopy eyes,” is a frequent observation that ranges from harmless daily buildup to a serious health concern. Tears are continuously produced to lubricate the cornea, provide nourishment, and flush away debris, and the residue of this natural process accumulates as discharge. Understanding the consistency, color, and timing of the discharge helps differentiate between a normal, benign occurrence and a symptom requiring immediate medical investigation.
Benign Causes of Eye Discharge
The most common and least concerning type of discharge is the small amount of dried matter that collects in the inner corner of the eyes after sleep. This morning mucus, sometimes called “sleep dust,” is a mixture of dried tears, oil, and environmental particles like dust. It typically appears clear, slightly cloudy, or as a light reddish-brown crust. This discharge should be consistent in amount and easily removed without causing discomfort to the dog.
Excessive clear, watery tearing, known as epiphora, is also often benign, particularly when triggered by minor environmental irritants. Dust, wind, pollen, or even the friction from a stray hair can cause the eyes to temporarily overproduce tears as a defense mechanism. This type of discharge generally subsides once the irritant is removed or the exposure ends.
Chronic epiphora can lead to tear staining, a reddish-brown discoloration of the fur beneath the inner corner of the eye, particularly noticeable in light-colored breeds. The staining itself is a cosmetic issue caused by porphyrins, iron-containing waste products excreted in the tears, which turn red-brown upon prolonged exposure to air. The underlying cause is often a minor obstruction in the nasolacrimal ducts or a breed-specific anatomical feature, such as shallow eye sockets, that causes tears to spill onto the face instead of draining normally.
Recognizing Symptoms Requiring Veterinary Attention
A change in the color or consistency of the discharge often signals a medical problem that warrants veterinary evaluation. Thick, opaque discharge that appears yellow, green, or gray typically indicates the presence of pus, which is an indicator of a bacterial infection, often associated with infectious conjunctivitis. If this colored discharge is accompanied by a red or swollen conjunctiva, pawing at the eye, squinting, or increased sensitivity to light, prompt treatment is required.
A thick, tenacious, grayish-white mucus that sticks to the eye’s surface is a hallmark sign of Keratoconjunctivitis Sicca (KCS), commonly known as dry eye. KCS is a condition where the immune system attacks the tear glands, resulting in insufficient production of the watery component of tears. Because the eye lacks the necessary lubrication, the remaining mucus becomes thick and sticky, causing irritation and making the eye susceptible to secondary bacterial infection.
Sudden onset of severe discharge affecting only one eye suggests trauma or the presence of a foreign body. Debris lodged in the eye or under the eyelid can cause intense irritation, leading to excessive watering, pain, and potentially a corneal ulceration. Any visible cloudiness or ulceration on the cornea, intense blinking, or the inability to fully open the eye constitutes an ophthalmologic emergency. Glaucoma, characterized by increased pressure, can also cause a sudden onset of excessive tearing, redness, and a dilated, unresponsive pupil.
Safe Cleaning and When to Seek Help
If the discharge is the clear or light crusty material associated with normal eye function, regular, gentle cleaning can prevent buildup and irritation. Use a clean, soft cotton ball or cloth moistened with warm water or a sterile ophthalmic saline solution. Wipe the area gently, always moving away from the eye itself, and use a fresh cloth for each eye to prevent cross-contamination.
Avoid using human-grade eye drops, as these are not formulated for canine eyes and may contain ingredients that cause harm or exacerbate irritation. Never attempt to force the eye open if your dog is squinting or showing signs of pain, as this suggests a serious underlying issue like a corneal scratch.
A visit to the veterinarian is necessary if the discharge changes from clear to yellow, green, or thick white, or if the amount suddenly increases significantly. Other concerning signs include redness of the eye, swelling of the eyelids, frequent pawing or rubbing at the face, or persistent squinting. These symptoms indicate pain or infection that requires a professional diagnosis and prescription medication.