What is feline corneal sequestrum?

Corneal sequestrum is a condition unique to cats in which a localised area of the cornea becomes necrotic, often appearing as a dark or cloudy plaque. A vet examination is needed to determine the cause and severity.

Does corneal sequestrum always require surgery?

Surgery is not always necessary. Mild cases may be managed conservatively, while more severe or non-healing lesions may require surgical evaluation and removal of the necrotic tissue.

How long does it take to see improvement after treatment?

Recovery time varies depending on the underlying cause. Some cats show symptomatic relief within days, but full corneal healing can take weeks to months. Regular follow-up appointments as directed by your vet are essential.

How can I reduce the risk of corneal problems recurring?

Keep the eyes clean, minimise the risk of physical trauma, and schedule regular check-ups for at-risk cats. If your cat has a chronic eye condition, discuss a long-term management plan with your vet.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Feline Corneal Sequestrum: Complete Guide to Symptoms, Diagnosis & Treatment [2025]

Corneal sequestrum is a condition unique to cats in which a dark, necrotic plaque forms on the cornea. It is often linked to chronic irritation or feline herpesvirus infection and may require surgical removal of the affected tissue.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ISFM, ACVO, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Heavy bleeding from the eye or a visible open wound
•Persistent severe light sensitivity with inability to open the eye or eat
•Obvious protrusion of the eyeball or visible corneal deformation

Schedule a Clinic Visit Soon (within 24–72 hours)

•Localized cloudiness or dark brown spot appearing on the cornea
•Continuously increasing or thick eye discharge
•Cat repeatedly rubbing or pawing at the eye without stopping

01What Symptoms Indicate a Problem?

Corneal sequestrum typically presents with corneal cloudiness, eye discharge, and signs of pain or discomfort.

Cloudy or dark brown/black spot on the surface of the cornea
Noticeable swelling or puffiness around the eye
Persistent or abnormal eye discharge (thick or purulent)
Redness of the sclera or conjunctiva with visible blood vessels
Squinting, frequent blinking, or light sensitivity

02How to Assess the Situation at Home: Key Observations & When to Go to the Emergency Vet

Monitoring the following at home can help you assess the severity and provide useful information to your vet.

Note your cat's alertness — whether they seem alert, lethargic, or less active than usual
Observe whether appetite or food intake has noticeably decreased
Record any changes in litter box habits, including diarrhoea or constipation
Weigh your cat or note any short-term changes in body weight for comparison
Monitor water intake and note any significant increase or decrease
If the eye worsens or signs of pain increase, seek veterinary attention promptly

03How Will the Vet Diagnose This? Common Examination Steps

At the clinic, your vet will carry out a systematic eye examination to identify the cause and assess the severity.

Full ophthalmic physical examination to assess pain response and visual reflexes

Slit-lamp examination to magnify and inspect corneal structures in detail

Cytology (swab or biopsy) to evaluate inflammation and infection characteristics

Bacterial culture and sensitivity testing to identify infection and guide antibiotic selection

Viral PCR testing to rule out common feline viral infections (e.g. feline herpesvirus)

Advanced imaging (e.g. CT scan) or referral to a veterinary ophthalmologist if indicated

04Treatment and Aftercare: Medications, Adjustments & Home Care Guide

Treatment is tailored to the underlying cause and severity, and may include medication, protective measures, and regular follow-up visits.

Topical or oral medications based on examination findings to control infection and inflammation
Protective measures such as an Elizabethan collar to prevent self-trauma and further abrasion
Home eye cleaning and medication administration must be carried out on schedule as directed by your vet
Regular recheck appointments to monitor corneal healing and vision status
Follow-up tests may include repeat cultures or viral testing to evaluate treatment response
Complex cases or non-healing lesions may be referred to a veterinary ophthalmologist for specialist care

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Act Quickly

Note when symptoms first appeared and how they have changed (onset date, whether worsening)

Record any recent changes in diet or water intake for your vet's overall assessment

Bring notes on litter box habits and any other abnormalities you have noticed

List all current or recent medications, eye drops, or supplements your cat has been given

Take close-up photos and short videos of the eye (front and side views) to aid the initial assessment

If possible, book ahead with a clinic that has ophthalmic experience or a veterinary ophthalmologist

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

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