TL;DR: Thick yellow eye discharge in cats typically indicates a bacterial or viral infection that requires veterinary care within 24-48 hours to prevent pain and permanent vision loss.
What does thick yellow eye discharge mean for my cat?
Thick yellow discharge, often referred to by veterinarians as purulent discharge, is typically an indication of a bacterial or viral infection. Unlike clear tears which might be caused by allergies, yellow or green mucus suggests that white blood cells are actively fighting an infection. This is commonly seen in cases of Feline Upper Respiratory Infection (URI), bacterial conjunctivitis, or an infected corneal ulcer.
Is my cat's eye discharge a veterinary emergency?
- The urgency level for this condition is Medium; while not immediately life-threatening, it is often painful and can lead to permanent scarring.
- You should aim to have your cat seen by a veterinarian within 24 to 48 hours to prevent the loss of vision.
- Seek care as soon as possible if your cat is squinting, pawing at the eye, or if the eye appears cloudy, as these are signs of a corneal injury.
How does providing a photo help with my cat's triage process?
- A high-quality photo allows triage professionals to see the exact color and consistency of the discharge and the degree of tissue inflammation.
- Since cats often squint or hide their eyes when stressed at a clinic, a photo taken in a relaxed home environment provides a more accurate view.
- Clear imagery helps your veterinary team assess the severity of the condition before you even arrive at the clinic.
Clinical Context (Merck Veterinary Manual)
In cats, a thick, yellow ocular discharge is commonly associated with infectious diseases such as feline herpesvirus-1, Chlamydia, and Mycoplasma, frequently presenting as acute and recurrent conjunctivitis. Secondary bacterial infections are also common, and broad-spectrum antibiotics (e.g., amoxicillin with clavulanic acid, cephalosporins, trimethoprim-sulfa, fluoroquinolones, tetracyclines, chloramphenicol) are useful. Tetracyclines and fluoroquinolones are particularly effective against *C. felis* and *M. felis*. Symptomatic treatment includes frequent removal of nasal and ocular discharge for patient comfort, and bland ophthalmic antibiotic ointments (tetracyclines in *C. felis* infections) applied 5-6 times daily can prevent corneal irritation.
Chapter: Infectious Disease, Ophthalmology
Source: The Merck Veterinary Manual, 11th Edition (Page 1482)