Yellow-green eye discharge in a dog can signify an infection that requires veterinary treatment. Potential causes include conjunctivitis, sinus infection and trauma to the eye. Prompt treatment protects the long-term health of your dog's eyes and vision. Veterinarians may prescribe eye drops or an ointment to treat the condition.
Do not administer eye drops designed for humans, and do not administer medication left over from a previous infection.
Conjunctivitis is an inflammation of the tissues that line the eyelids and front of the eye. Conjunctivitis may occur in one or both eyes. Common symptoms include yellow-green discharge from the eye, redness around eye tissues, squinting, excessive blinking and swelling of tissues around the eye.
Potential causes of conjunctivitis include bacterial infections, canine distemper virus, allergies, tumors and other eye diseases. Your vet will prescribe a treatment based on the cause of the conjunctivitis -- for example, antibiotic ointments to treat bacterial infections. If the cause is allergies, you and your vet will identify the allergen and remove it from your dog's environment if possible.
Scratches and Foreign Matter
Even a minor scratch on your dog's eye may become infected and cause yellow-green discharge. Injuries may be caused by foreign objects, abnormal eyelash growth, pawing the eye, contact with chemicals or fights with other animals. Your vet will prescribe medication to fight infection. Additional treatment may be necessary depending on the severity of the injury.
Glaucoma elevates the pressure inside a dog's eye, resulting in vision loss or complete blindness. It may occur on its own or as the result of another condition such as uveitis, eye injury or tumors.
Symptoms include green or yellow eye discharge, tearing, large pupils that don't react to light, and a blue tinge to the eye. Medication is rarely effective in treating glaucoma in dogs. Surgery is often recommended if the vet thinks your dog's vision can be saved.
Various Viral Infections
Although the primary symptom of kennel cough is a dry, hacking cough, dogs with severe cases may also have yellow-green eye or nasal discharge, fever and difficulty breathing.
Canine Distemper Virus
Canine distemper virus kills as many as 80 percent of unvaccinated puppies who become infected. Common symptoms include discharge from the eyes and nose, fever, lethargy, appetite loss, diarrhea and dehydration.
Rocky Mountain Spotted Fever
Dogs can contract Rocky Mountain spotted fever from ticks carrying the virus. In addition to experiencing pus discharge from the eyes and nose, dogs experience fever, coughing, face and joint swelling, joint pain, vomiting, diarrhea and neurological problems.
Rabbit fever, or tularemia, is a potentially fatal disease that causes fever, lethargy and eye and nasal discharge in dogs. Tularemia is common in wild rabbits. Dogs can contract the disease by ingesting an infected animal or from a tick or fly bite.