A corneal sequestrum is a brown or gold-colored area of degenerated corneal tissue that is similar to a scab. These tend to affect areas on the cornea where there has been long standing irritation. Corneal sequesta typically occur in cats. Any breed of cat can be affected, however, the Siamese, Persian, Himalayan, and Burmese breeds are particularly susceptible.
Sequestra may range from being very superficial to extending deep into the cornea. They can cause the cornea to crack (ie ulcerate) or can fall out, leaving a deep defect that can predispose the eye to rupture. In addition, sequestra can lead to ocular infections, corneal scarring, corneal vascularization and corneal mineralization. Some of these conditions are painful, thereby resulting in squinting, excess tearing or discharge, rubbing, and behavioral changes such as hiding, increased sleeping, and reluctance to eat. Therefore, it is important that you contact Eye Care For Animals or your veterinarian if your cat experiences any of these changes, or if you notice a gold/brown colored area on the cornea.
Causes
Corneal sequestra can occur as the result of chronic eye irritation. Potential causes for such irritation include low tear production, decreased blink response and an underlying Feline Herpesvirus infection. In addition, flat-faced cat breeds have more prominent eyes and decreased corneal sensation, which makes them more prone to corneal irritation and therefore sequestrum formation.
Treatment
Treatment for a corneal sequestrum usually involves a surgical procedure called a keratectomy. This involves removing the affected layers of the cornea and requires that your pet is under general anesthesia. Our veterinary ophthalmologists perform these surgeries using an operating microscope and specialized microsurgical instruments. Surgery relieves the discomfort associated with the corneal sequestrum, prevents the lesion from deepening and greatly shortens the healing time of this condition.
Occasionally, corneal sequestra fall out on their own and therefore don’t require surgery. However, if this process occurs with a deep sequestrum, the remaining cornea may become very fragile or even rupture. Also, the sequestrum may become much larger and deeper while you wait for it to fall out. Therefore, surgery is often recommended to prevent these events while significantly shortening the recovery time.
It is important to realize that, although keratectomy and graft procedures are considered to have low risk, the chance for complication is possible. For example, there is always a risk associated with being under general anesthesia. Other potential complications include, but are not limited to:
- Inflammation of the pink tissue (conjunctivitis)
- Rejection of the graft
- Infections of the surgical site
- Corneal ulcerations (superficial to deep)
- Corneal scarring, vascularization, or mineralization
- Rupture of the eye, secondary to ulceration
- Infammation inside the eye (uveitis)
- High pressure within the eye (glaucoma), secondary to uveitis
- Retinal detachment or degeneration, secondary to uveitis or infection
- Ocular or orbital pain, secondary to uveitis, glaucoma or infection
- Ocular irritation leading to rubbing of the eye
- Bleeding inside the eye (hyphema)
- Excessive tearing or watering of the eye
If you have any questions about Corneal Sequestrum, please do not hesitate to call us at Eye Care for Animals.
