A corneal sequestrum in your cat's eye can put them at risk of losing their eyesight. Today, our Renton vets discuss the causes, signs, and treatment of feline corneal sequestrum.
A Corneal Sequestrum in Cats
Have you noticed your cat consistently rubbing or pawing at its eye, or signs of discharge? If so, they must see a vet because they may have a corneal sequestrum, which is an opaque, dark brown to black spot on the cornea.
This spot is plaque — a dead piece of corneal tissue. Typically oval to round, sequestra can vary in size from very small to quite large, and may extend deep into the corneal tissue.
The condition is unique to domestic cats and can occur in kitties of all breeds and ages. Medication and surgical treatment options are available, so it's possible for cats to fully recover with proper treatment.
Causes of a Feline Corneal Sequestrum
We do not know all the reasons why some felines develop this condition, but one of the most common causes of a corneal sequestrum in cats is the feline herpes virus. Other eye injuries and trauma can also cause the disease. These include:
- Dry eye syndrome
- Abnormal eyelid conformation
- Corneal trauma such as accidental scratches
Persian and Himalayan cat breeds are frequently affected, so genetics and conformation may also play a role.
Clinical Signs of a Corneal Sequestrum in Cats?
If your cat has developed a corneal sequestrum, initial signs may be subtle and include:
- Elevation of the third eyelid
- Squinting, tearing, and other signs of pain
- Change in color of the cornea from clear to brown or black
- Blood vessels extend from the edge of the eye to the sequestrum
In some cats, the infection can develop in the cornea surrounding the sequestrum, or the sequestrum may be so deep that it can affect the entire thickness of the cornea, putting your cat at risk of losing the eye.
Diagnosing a Corneal Sequestrum
Our Renton veterinary ophthalmology team has experience in diagnosing and treating many eye injuries and diseases. We can conduct a clinical examination of your cat's eye to determine if the tell-tale black or dark-colored plaque is present in the corneal stroma.
Treating Feline Corneal Sequestrum
Surgical removal (lamellar keratectomy) is the preferred treatment option for this condition since sequestra can cause pain, inflammation, ulcers, and irreparable damage.
A veterinary ophthalmological surgeon will use an operating microscope and micro-surgical ophthalmic instruments to perform the procedure while your cat is under general anesthesia. The corneal sequestrum and surrounding necrotic (dead) tissue will be removed before a topical antibiotic is applied to the eye. Superficial lesions may be manually debrided with topical anesthesia.
A conjunctival grafting or corneal transplant may be recommended for cats who have a deep sequestrum. Your vet will also likely recommend long-term artificial tear supplements for both eyes to prevent the condition from recurring.
Your veterinary surgeon may also recommend medications such as antivirals and topical antibiotics along with oral pain medication and ocular lubricants to keep the cornea moist and prevent further irritation.
A Cat's Recovery From Surgery
Your veterinarian may recommend an Elizabethan collar (E-collar) to prevent further injury or secondary infections after the procedure.
Remember that pain associated with ocular surgery and the application of topical medications (particularly some antiviral agents) often worsens immediately after surgery before it improves gradually. Antiviral drugs may be used to address an underlying feline herpesvirus infection.
Atropine can help to dilate the pupil and relieve pain. While it can be applied every 12 to 24 hours, it should only be used as long as necessary, then tapered off as prolonged use can decrease tear production.
The Prognosis for a Corneal Sequestrum in Cats?
If the disease is surgically treated, your cat has a good chance of living with a pain-free eye and having normal clinical vision, especially if the sequestrum is removed and treated early.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.