Cat Corneal Sequestrum: Dark Eye Plaque Signs and Surgery

A feline corneal sequestrum is a dark brown or black plaque of dead corneal tissue that forms in response to chronic irritation or ulceration. It causes chronic eye pain and can impair vision. Surgical removal (keratectomy) is the definitive treatment and usually results in an excellent outcome with appropriate aftercare.

Last reviewed: June 2026

What Is a Corneal Sequestrum in Cats?

A corneal sequestrum (plural: sequestra) is a focal area of corneal stromal necrosis — essentially, dead tissue that becomes sequestered within the cornea, turning a characteristic dark brown to black color. It is unique to cats and is not seen in dogs or most other species. Persians, Himalayans, Burmese, Siamese, and other brachycephalic (flat-faced) breeds are predisposed because their facial anatomy causes reduced blinking and abnormal tear film distribution.

Contributing causes include:

• Chronic corneal ulceration or recurrent trauma
• Feline herpesvirus-1 (FHV-1) infection — the most common underlying trigger (Helps et al., 2005, JFMS)
• Entropion (inward rolling eyelids) or other eyelid abnormalities
• Inadequate tear production (keratoconjunctivitis sicca, or KCS)
• Foreign bodies or abnormal hairs rubbing the cornea

Sequestra start as a small tan discoloration and slowly deepen to dark brown or black over weeks to months as necrosis progresses.

Signs to Watch For

• A dark brown, amber, or black spot or plaque on the surface of one (rarely both) eyes
• Squinting, winking, or keeping the eye partially closed
• Excessive tearing or discharge from that eye
• Pawing or rubbing at the affected eye
• Reduced vision or reluctance to navigate in low-light conditions
• The affected eye may appear red or inflamed around the periphery

Some cats appear to tolerate small, superficial sequestra with minimal discomfort; others are intensely painful. Severity correlates with depth more than size.

Treatment Options

Medical management (superficial, non-painful cases): Antiviral eye drops (idoxuridine or cidofovir) may slow progression if FHV-1 is the underlying cause, but rarely resolve an established sequestrum. Lubricating eye drops reduce secondary irritation.

Surgical superficial keratectomy: The definitive and preferred treatment. Under general anesthesia, the ophthalmic surgeon removes the necrotic corneal tissue with microsurgical instruments. As described in Slatter's Textbook of Small Animal Surgery, keratectomy is highly effective, with recurrence rates of 10–25% in herpesvirus-positive cats. Postoperative care includes topical antibiotics, antiviral drops (if FHV-1 is involved), and an Elizabethan collar for 3–4 weeks during healing.

After surgery, a superficial scar (nebula) remains — the cornea rarely returns to full clarity, but vision and comfort are typically much improved. Cats with herpesvirus require long-term antiviral management to minimize recurrence risk.

When to See a Vet

Call your vet today if:

• You notice any dark discoloration on your cat's eye, even small — sequestra worsen over time
• Your cat is squinting, tearing excessively, or pawing at their eye
• Your cat has a history of herpesvirus and a new eye problem has developed
• Your flat-faced cat has had recurring eye irritation or discharge

Go to the ER immediately if:

• The eye appears to be rupturing or bulging abnormally
• Severe and sudden squinting with complete closure of the eye
• The corneal surface looks irregular, perforated, or has a liquid-filled bleb
• Discharge is purulent (thick, green or yellow) and the eye is swollen shut

Frequently Asked Questions

How much does corneal sequestrum surgery cost in cats? A veterinary ophthalmologist consultation runs $150–300. Superficial keratectomy under anesthesia typically costs $800–1,800 at a specialty center, including anesthesia monitoring, the surgical procedure, and postoperative medications. Follow-up exams add $100–200 each. Total first episode cost is commonly $1,200–2,500.

Can a corneal sequestrum resolve on its own? Occasionally, a very superficial sequestrum will slough off naturally, but this is unpredictable and can leave an ulcer that itself requires treatment. Most veterinary ophthalmologists recommend surgical removal rather than waiting, because untreated sequestra deepen over time and become more painful and harder to remove.

Will my cat's vision return to normal after surgery? Most cats regain functional, comfortable vision after keratectomy. A faint scar usually remains at the removal site, and cats with central sequestra may have mild visual impairment. For most cats, the outcome is a dramatic improvement in comfort and quality of life.

Which cat breeds are most at risk for corneal sequestrum? Persian, Himalayan, Burmese, Siamese, and Ragdoll breeds are most commonly affected. The combination of shallow orbits, reduced blink reflex, and possible herpesvirus exposure makes brachycephalic cats especially vulnerable.

Can I prevent corneal sequestrum in my cat? Keeping herpesvirus well-managed with L-lysine supplementation (though evidence is mixed) or antiviral treatment during flares, using lubricating eye drops in brachycephalic cats, and promptly treating any eye irritation or ulceration reduces the risk of sequestrum development.

Still Not Sure if Your Cat Needs a Vet?

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