Iris Prolapse in Cats

Feline Iris Prolapse

Iris prolapse is the protrusion or forward movement of the iris, the tissue that makes up the pupil, through a traumatized or perforated cornea. It is a common sequel to penetrating corneal wounds and/or ruptured corneal ulcers in cats. Due to the traumatic nature of most cases of iris prolapse, animals prone to fighting may be predisposed.

Iris prolapse usually has an acute onset associated with a traumatic incident. The protruding iris is often covered with a blob of mucus that appears yellow or white. The underlying iris itself is usually brown-black in color.

What to Watch For

• Swelling and clouding of the eye, particularly the cornea
• Ocular pain with marked squinting and tearing
• Possible presence of an ocular foreign body
• Blood in the eye
• Distortion of the pupil

Diagnosis of Iris Prolapse in Cats

• A complete history and physical examination are performed to determine the possible cause of the lesion and to identify any other injuries or abnormalities.
• A thorough ocular examination is indicated, but this must be done with caution so that the eye does not rupture. The use of local anesthetic agents or sedation may be required to complete the examination. The appearance of the lesion is diagnostic.
• A culture may be taken from the surface of the eye and the cornea may be stained with fluorescein.
• The eye exam attempts to determine whether the eye is salvageable or whether it might need to be removed. Your veterinarian may refer your cat to a veterinary ophthalmologist for further evaluation and surgery.
• A complete blood count, biochemical profile, and urinalysis are usually within normal limits, but they may be performed as part of a preoperative evaluation.

Treatment of Iris Prolapse in Cats

Iris prolapse is an ocular emergency and requires immediate medical and surgical therapy. Medical treatment includes the following:

• Topical antibiotic drops are instituted, often every few hours.
• Topical atropine may be started to try and dilate the pupil and pull the remaining iris away from the corneal wound.
• Systemic antibiotics are started by mouth or by injection.
• An Elizabethan collar is applied so that the animal does not traumatize the eye further.

The type of surgery recommended depends on the viability of the eye:

• If the interior of the eye is reasonably healthy, if there is still some chance of vision, and if the iris prolapse is recent, then the preferred treatment is surgical repair of the eye. Surgical repair involves replacement of any healthy iris or removal of any unhealthy iris tissue and closure of the corneal defect. If possible, this surgical repair is done right away.
• If the interior of the eye has collapsed, is infected, or is filled with blood, or if the cornea is too damaged to be repaired, then the eye may need to be removed (enucleated).

Home Care and Prevention

If the cornea is surgically repaired, then it is very important to administer all medications precisely as directed by your veterinarian. The treatments following this type of surgery are labor-intensive and must be done on a consistent schedule. Numerous rechecks are also required to ensure that the eye is healing well and that no complications are developing.

The postoperative care following an enucleation is simpler and may involve giving oral antibiotics and returning for a suture removal in 10 to 12 days. The cat may be required to wear an Elizabethan collar after both surgeries.

Take care when introducing new cats to households with other cats, especially if those cats have front claws. Introduce the cats slowly and under supervision. Provide a mechanism whereby the cats can escape from each other. It may take several days to several months before the other cats will accept the new cat.

Make sure your male cat is neutered so he is less likely to fight. Try to keep cats indoors or within their own yard in order to minimize catfight injuries.