Dark Spots on the Eye in Cats: Understanding Corneal Sequestrum

When it comes to our beloved feline friends, their health and well-being are always a top priority. One particular eye condition that cat owners should be aware of is corneal sequestrum. In this article, we will delve into what corneal sequestrum is, its symptoms, causes, diagnosis, and available treatments.

What is Corneal Sequestrum in Cats?

Corneal sequestrum refers to the presence of dead corneal tissue, which appears as dark spots on the eye. It is often caused by chronic corneal ulceration, trauma, or corneal exposure. While corneal sequestrum can affect cats of any breed, Persian and Himalayan breeds are more susceptible to this condition. Typically, it develops during a cat’s middle-aged years.

Symptoms and Types

The dark spots on your cat’s cornea may remain unchanged for long periods and suddenly worsen. Here are some other symptoms your cat may exhibit:

  • Discoloration of the affected corneal area, ranging from a translucent golden-brown color in the early stages to an opaque black.
  • Chronic non-healing corneal ulcer.
  • Abnormal corneal cell formation, leading to swelling and protrusion.
  • Episodes of feline herpesvirus-1 (FHV-1).
  • Dry eyes.
  • Eyelid twitches and/or ocular discharge, which can range from clear to brownish-black mucus or pus.
  • Blood in the outer surface of the eye and swelling.
  • Constriction of the pupil.


While the exact cause of corneal sequestrum in cats remains unknown, several risk factors have been identified:

  • Chronic corneal ulceration.
  • Chronic irritation.
  • Ingrown eyelashes or entropion (eyelids folding inward).
  • Shortened nose and face conformation, particularly in Persian and Himalayan breeds.
  • Incomplete blink.
  • Dry-eye syndrome.
  • Tear film disorders.
  • Feline herpesvirus-1 infection.
  • Topical drug use, such as corticosteroids.
  • Recent surgery.
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To diagnose corneal sequestrum, your veterinarian will consider the following:

  • Corneal perforation, indicated by a protruding iris with fleshy appearance and yellow to light brown color.
  • Corneal pigmentation, which is rare in cats.
  • Corneal tumor, typically benign and found at the border of the cornea. This tumor is not usually painful.
  • Corneal foreign body.


The chosen course of treatment depends on the depth of the lesion and the degree of ocular pain your cat experiences. In some cases, the blemish may slough off spontaneously, but timing is crucial. Should you decide to wait, supportive care is essential.

While surgery is generally avoided, it may become necessary if the pain persists for an extended period. Surgical options include:

  • Lamellar keratectomy: This procedure involves removing thin layers of the corneal tissue. When performed early, it can alleviate pain, speed up corneal healing, and prevent the lesion from affecting deeper corneal tissue.
  • Corneal grafting procedures: If more than 50 percent of the corneal connective tissue has been removed, corneal grafting may be recommended.
  • Postoperative corneal ulcer management: After surgery, your cat will require a broad-spectrum topical antibiotic, atropine ointment, and a tear supplement to aid in the healing process.

Living and Management

If your cat is managed with medications, regular weekly examinations will be necessary to monitor any potential complications, such as the lesion separating itself from the surrounding tissue. In cases where a keratectomy procedure is performed, your cat’s eye should be re-evaluated every seven to ten days until the corneal defect has fully healed.

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It’s important to note that corneal sequestrum can potentially affect the other eye, especially in cats with small tear production, thick lesions, or if pigmented corneal tissue is not removed. This recurring condition requires ongoing care and attention to ensure the well-being of your feline companion.

For more information on cat eye health and to find trusted professionals who can provide the care your cat needs, visit Katten TrimSalon today.