Ocular discharge

What It Is

Some tearing is normal in most species, but discharge becomes a concern when it increases, changes color, or starts to mat the fur or feathers around the eye. Clear, watery discharge often signals irritation or a blocked tear duct, while thick yellow or green discharge points toward infection. Dogs with short, flat faces and certain cat breeds are prone to chronic tear overflow simply because of their facial shape. Birds and reptiles can also show ocular discharge, often linked to poor air quality or an underlying respiratory infection.

Common Causes

Conjunctivitis, an inflammation of the pink tissue lining the eye, is one of the most frequent causes and can come from allergies, irritants, or infection. A scratch or foreign body on the surface of the eye causes sudden, often one-sided discharge along with squinting. Blocked tear ducts lead to constant overflow down the face without other signs of pain. Upper respiratory infections in cats and in pet birds commonly cause discharge from both eyes alongside sneezing or nasal discharge. Dry eye, where the eye fails to produce enough of its own tear film, causes a thick, ropey discharge over time.

When It Is an Emergency

Discharge paired with a visibly cloudy, bulging, or painful eye, or with the animal holding the eye shut and pawing at its face, needs same-day attention, since some causes can threaten vision within hours. Any discharge following a suspected eye injury, such as a cat fight or a scratch from a plant, should be checked promptly rather than treated at home. Sudden discharge from both eyes in a young kitten or puppy alongside lethargy or poor appetite also warrants prompt care.

What the Vet Will Do

The vet examines the surface of the eye closely, often using a stain that highlights scratches or ulcers under blue light. Tear production can be measured with a small paper strip placed against the lower lid. Depending on what the exam shows, treatment might include antibiotic drops, a test for the herpesvirus common in cats, or a closer look at tear duct drainage.

Home Care and Prevention

Gently wipe away crusted discharge with a warm, damp cloth rather than letting it dry and pull at the fur. Do not use any leftover human or pet eye drops without checking with a vet first, since the wrong product can worsen certain conditions. Keeping facial fur trimmed around the eyes in breeds prone to tear staining reduces irritation. Routine grooming and prompt attention to any squinting or redness catches most causes early, before they progress.