What is a corneal sequestrum?
This condition is commonly seen in cats and is characterized by an area of corneal degeneration with brown pigmentation in one or both eyes. Sequestra are usually oval to round, they can be small to quite large, and they can extend deeply into the corneal tissue.
Are certain breeds more likely to develop a corneal sequestrum?
Yes. The disease is diagnosed most frequently in Persians, Himalayans, Siamese and Burmese cats. However, corneal sequestration can occur in cats of all ages and breeds.
What causes a corneal sequestrum?
The exact cause of feline sequestra is unknown. However, the development of a sequestrum is often associated with corneal trauma, corneal ulceration, abnormal eyelid conformation, and/or Feline Herpes Virus infection. Genetics and conformation may also be involved since there is a definite breed predisposition. An ophthalmic examination is essential to uncover any underlying problems.
What are the signs of a corneal sequestrum?
A brown to black oval to round spot is visible on your cat's cornea. Sequestra can be painful. The signs of ocular pain may be subtle and include squinting, tearing, and elevation of the third eyelid. Sequestra can remain for months to years and can cause secondary inflammation and/or infection. A sequestrum can extrude (slough) from the eye's surface and may cause rupture of the eye, which represents an ocular emergency.
How is a corneal sequestrum treated?
Early surgical removal of the sequestrum is the treatment of choice. The surgical procedure to remove a sequestrum is called a partial lamellar keratectomy. This surgery is performed using an operating microscope, micro-surgical ophthalmic instruments, and with the patient under general anesthesia. If the sequestrum is deep, a conjunctival graft or a corneal transplant is sutured into the defect.
What is the prognosis?
The prognosis for the eye to be free from pain and to have normal clinical vision is good with surgery, especially if the sequestrum is removed at an early stage. However, recurrence is possible. A sequestrum may also develop in the other eye.