TL;DR: A cat’s eye swollen shut with pus is a high-priority medical emergency that requires immediate veterinary intervention to prevent permanent blindness or eye rupture.
What does it mean if my cat's eye is swollen shut and producing pus?
When a cat's eye is swollen shut and producing pus—which typically appears as thick yellow, green, or grey discharge—it is a sign of a significant underlying issue. This often points to a severe bacterial or viral infection, a corneal ulcer (a painful scratch on the eye surface), or a penetrating injury from a cat fight or environmental hazard. The swelling is an inflammatory response, while the pus indicates the body is actively fighting an infection.
Is a swollen eye with discharge a veterinary emergency for my cat?
- Urgency Level: High. A cat eye that is swollen shut is always considered a medical emergency.
- Rapid Escalation: Feline eye issues can progress from minor irritation to permanent blindness or a ruptured globe within hours.
- Critical Symptoms: Seek immediate care if your cat is also lethargic, pawing at the eye, or refusing to eat.
- Professional Action: Do not wait for the eye to "clear up" on its own; immediate intervention is required to manage pain and prevent vision loss.
How can taking triage photos help my cat's eye condition?
In a triage situation, providing a clear photo of the eye to your veterinarian can be life-saving. A high-quality image provides several benefits for the medical team:
- Allows assessment of the severity of the swelling and the nature of the discharge.
- Identifies whether the eyelid is protruding.
- Helps the clinic determine how quickly your cat needs to be seen.
- Enables staff to prepare diagnostic tools, such as fluorescein stains or tonometry, before you arrive.
Clinical Context (Merck Veterinary Manual)
Ophthalmic emergencies require rapid diagnosis and treatment to maintain vision. Swelling of the zygomatic gland, located just caudal to the eye, can cause retrobulbar swelling, divergent strabismus, exophthalmos, excess tearing, and reluctance to open the mouth or eat. Abscesses of the zygomatic gland are acutely painful, and affected animals may hold their head rigidly and resent any manipulation involving the head or neck. While radiographs and laboratory tests are typically not helpful, evaluation of fluid from an abscess can lead to a diagnosis. In cases of swelling behind the last molar, drainage is indicated, along with warm compresses and topical lubricants to protect the cornea. Prolapse or proptosis of the eye can also occur due to trauma, though it is infrequent in cats.
Chapter: Ophthalmology, Emergency
Source: The Merck Veterinary Manual, 11th Edition (Page 1696)