FELINE CORNEAL SEQUESTRATION

A Feline Corneal Sequestrum is a condition unique to cats. It can occur in any breed but is especially common in Persians, Himalayans, Colorpoints, Abbysinians and Burmese. Cats of any age can be affected.

This is when a black or brown spot develops in the cornea. It may or may not be associated with corneal vascularization (blood vessels).

Feline Corneal Sequestration may develop without any obvious cause, or they may also follow viral infections e.g. cat flu (feline herpes virus), corneal ulcers, or from irritation.

In some cases new Feline Corneal Sequestration lesions can develop in the same eye or in the other eye, this is especially common in Persians.

In early cases we have had some cases respond to topical drops. These drops may need to be applied for 1 to 2 months before any response is seen. We seem to get the best response to this therapy in cases where there is just slight discoloration to the cornea.

Surgery

There are three surgical options for treating corneal sequestrums. All surgeries are done under an OPERATING MICROSCOPE.

Superficial Keratectomy:

A superficial keratectomy involves separating the diseased surface layers from the normal underlying cornea. After the keratectomy is performed either a third eyelid flap or a temporary tarrsorraphy (stitching the eyelids together) are placed to protect the cornea whilst it is healing. This suture will be removed at one of the post operative visits.

Conjunctival Pedicle Flap:

A conjunctival pedicle flap is used for patients with deep sequestra or patients that are predisposed to recurrence. These patients include those under the age of 8 years and Persians. Firstly a keratectomy is used to remove the diseased cornea. Then a thin tongue of conjunctiva is dissected off the sclera and sutured directly onto the cornea using 8-0 or 9-0 suture material. As with a superficial keratectomy a temporary tarrsorraphy is placed.

Conjunctival Pedicle Graft immediately after surgery
Image supplied by Dr. Anu O'Reilly

Clear Corneal-Conjunctival Transposition:

For certain cases a clear corneal-conjunctival transposition can be used to treat deep cases and those prone to recurrence. Firstly a keratectomy is performed to remove the diseased cornea. Then a section of adjacent normal cornea is undermined to the edge of the eye and into the conjunctiva. This entire section is then transposed over and onto the keratectomy site. The transposed tissue is then sutured down onto the cornea and a temporary tarrsorraphy is placed.

After surgery

2 week post op

3 Months later

3 Months later

Images supplied by Dr. Anu O'Reilly

Prognosis

Conjunctival pedicle grafts and clear corneal-conjunctival transposition appear to prevent the recurrence of sequestrums. There is a 5% chance that a conjunctival pedicle graft may dehisce (contract and pull out due to poor blood supply).

Post Operative Care

The following concerns will be discussed with you at the time of the initial consult.

1. Visits following surgery

2. Antibiotic tablets or paste after surgery

3. Anti-inflammatory tablets or liquids after surgery

Please let us know at the time of the initial consult if your pet is currently taking any medications (tablets, paste or liquid) or has any health issues.

Following surgery it is possible for unusual reactions to develop on the cornea. These may include corneal scarring and eosinophilic keratitis. These complications are unpredictable and may require prolonged therapy.