Proptosis is displacement of the eyeball out of the eye socket, so that the eyelids become trapped behind the eye. As cat's eyes are firmly set into the bony socket, serious facial or head trauma is required to proptose an eye.
Proptosis in the cat is generally associated with significant facial trauma, such as that received from an automobile related injury or a fall from a great height. The prognosis for retaining vision after proptosis is poor to guarded in the cat.
Proptosis is considered a true eye emergency. The cornea (superficial, clear layer of the eye) is stained with fluorescein to detect cuts, scratches or abrasions on the surface.
Diagnosing proptosis is based on physical exam findings. The eye protrudes from the socket with the eyelids curled behind it. The lids cannot cover the eye and the surface of the eye rapidly becomes dry and discolored.
Since most proptosed eyes in the cat occur from head trauma, a thorough physical exam concentrating on the face is crucial. Examination may reveal other potentially serious complications, such as fractures of the bones of the face and jaw or serious injuries to the nose and brain.
Examination of the eye must also be done to determine the extent of injury. This can help determine the course of treatment.
The interior of the eye is examined for bleeding within the eye or inflammation in the front chamber of the eye.
The muscles, skin and nerves attached to the proptosed eye are also examined.
Initially, lubricant or antibiotic ointments are applied to the injured eye in an attempt to reduce further damage to the cornea. Based on the severity of injury, the treatment options are removal of the eye (enucleation) or surgical replacement of the eye into the socket. Unless the eye is severely damaged, replacing the eye and allowing it time to heal is the preferred treatment. A stable cat is placed under general anesthesia. The eye is gently pushed back into the socket, and the eyelids are sutured closed over the eye. This surgery is called a temporary tarsorrhaphy.
A major complicating factor in the treatment of proptosis in cats is that they frequently also have serious head injuries. These head injuries, particularly brain concussions, do not allow the cat to be anesthetized right away for eye surgery. It may take several days of intensive care before a cat is stable enough to be anesthetized, and by that time the eye is irreversibly damaged and must be removed.
After replacing the eye, the eye is treated with topical antibiotics and atropine ointment. These help the cornea to heal and help decrease the cat's pain. Systemic antibiotics may also be given.
After one to two weeks, the eyelid sutures are removed. At this point, the eye is re-evaluated and vision tests are performed.
If the cat is not stable, it is treated with intensive care for several days. Once stable, the cat is placed under general anesthesia. The eye is enucleated and any fractures of the jaw or roof of the mouth (palate) are repaired. At the end of the enucleation, the eye socket is permanently sutured closed. See also the article on Enucleation in cats.
Unfortunately, the prognosis for vision in cats with proptosis is poor. This is due to the degree of trauma that is required to proptose a cat's eye. Even if the cat loses vision, rapid treatment can result in salvaging the eye for cosmetic reasons.
Home Care and Prevention
If you notice your cat has a proptosed eye, prompt veterinary attention is required.
Once home after treatment, many cats must wear an Elizabethan collar to prevent pawing or rubbing at the sutured eye. Keep the collar on at all times, unless the animal is supervised.
If the eyelids have been sutured closed, examine them daily. Watch for signs of swelling, bleeding or yellow-green, infected discharge, and notify your veterinarian should they occur. Apply medications to the eye as prescribed. Notify your veterinarian immediately if you are having trouble giving any medications.
The only way to prevent proptosed eyes is to try to prevent the trauma that leads to the problem. Keeping your cat indoors significantly reduces the chance of this type of trauma.