Enlargement or Bulging of the Eye in Cats

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Last updated on
3 min read

Key takeaways

A bulging eye in cats may be characterized as abnormal enlargement of the eyeball (referred to as buphthalmos) or as protrusion of the eye beyond the socket (referred to as exophthalmos). Both presentations are uncommon in cats.

  • Buphthalmos is often associated with high intraocular pressure due to swelling of the globe (aka glaucoma)
  • Exophthalmos is usually associated with increased pressure behind the eye from cancer or inflammation, or following severe head trauma
  • Bulging eye is a painful medical emergency requiring prompt veterinary attention
  • Diagnosis is usually made through observation, but determining the underlying cause may require special equipment, diagnostic imaging, and other laboratory tests
  • Treatment depends on the underlying cause and ranges from medications to surgery
  • The prognosis depends on the underlying cause and whether there was any trauma to the nerves of the eye or surrounding tissues
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A closer look: Enlargement or Bulging of the Eye in Cats

Buphthalmos and exophthalmos are uncommon in cats. Cats exhibiting symptoms of eye bulging or protrusion require emergency veterinary care for the best chance of vision preservation and a positive outcome.

Possible causes

Risk factors

Bulging or protrusion of the eye(s) can vary from barely noticeable to extreme, and can be bilateral or unilateral. Push-face breeds like Persian or Scotch fold cats are at higher risk of bulging eyes due to facial abnormalities.

Testing and diagnosis

Diagnosis of a protruding or bulging eye can be made by gross observation. Identifying the root cause is important to determine treatment as well as prevent future incidents. A thorough ocular examination is required. Further testing is often needed, sometimes requiring specialized equipment; referral to a veterinary ophthalmologist may also be necessary.

Diagnostic tests may include X-rays, ultrasound, MRI, or CT to view inside and behind the eye. Swabs from the surface of the eye or biopsies of tissues around the eye may also be recommended.

Treatment in general centers around trying to save the affected eye. This may involve antibiotics, antifungals, topical drops or ointments, chemotherapy, or surgery. In many cases, the ultimate result is surgical removal of the eye (enucleation). Cats adapt well to living with lost or decreased vision.

Depending on the underlying cause, euthanasia may be the best option.

Similar symptoms

Bulging eye is self-evident and not likely to be confused with other symptoms. Pet parents might not be able to determine if their cat has buphthalmos versus exophthalmos without veterinary consultation.

Associated symptoms


Krista Williams, BSc, DVM, CCRP; Tammy Hunter, DVM; Cheryl Yuill, DVM, MSc, CVH - Writing for VCA Animal Hospitals
Ralph E. Hamor , DVM, MS, DACVO - Writing for Merck Veterinary Manual
Ralph E. Hamor , DVM, MS, DACVO - Writing for Merck Veterinary Manual
- Writing for Wag!
Dr. Bari Spielman - Writing for PetPlace
Lynne S. Sandmeyer, Bianca S. Bauer, and Bruce H. Grahn - Writing for The Canadian Veterinary Journal

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