By Kim Everson, DVM
No, it’s not a Halloween mask.
And it certainly isn’t a trick.
What’s happened to this little dog is an eye emergency called “proptosis.”
Essentially Ollie’s* eyeball popped out of his head and became trapped in front of his eyelids. This is an emergency for Ollie because 1) it’s very painful (hence the muzzle), and 2) may cause him to go blind in that eye.
How does this sort of thing happen? And what is to be done for poor Ollie?
Proptosis happens most frequently in what we veterinarians call brachycephalic breeds (“brachy” meaning short and “cephalic” meaning head) like pugs and shih tzus because their large, protuberant eyeballs don’t sit deeply enough inside their shallow eye sockets. Chihuahuas like Ollie are also highly susceptible to proptosis for this reason. Ironically, what makes Ollie’s sweet baby face so irresistible also predisposes his eyes to serious injury.
Despite his skull’s predisposing anatomic features, Ollie’s eyeball did not just pop out of his head for no reason. Like other proptosis cases, Ollie experienced a sudden trauma which caused his eyeball to be forwardly displaced. Sometimes this trauma is caused by a fall or blow to the head, but oftentimes it results from a dog fight. Indeed, the morning of his injury Ollie instigated one too many altercations with his much larger husky housemate, Turbo. A quick snap from Turbo caught Ollie just right, causing his eyeball to proptose but remarkably causing no damage to his skull or skin. As the owner pointed out, if Turbo had meant to kill Ollie he would have. It was an accident pure and simple.
Fortunately, Ollie’s owner was on the telephone with us immediately, it being pretty clear that Ollie needed emergency care for his bizarre looking injury. Intuitively, she recognized Ollie’s vision was at stake, and he was clearly in pain.
After a rapid assessment, Ollie was placed under anesthesia for proptosis repair. His eyeball was rinsed with sterile saline to remove dust and hair, and a special stain called fluorescein was dripped onto his cornea (the clear, domed covering over the colored iris and black pupil) to assess for abrasions. Amazingly, his cornea was in great shape. Ollie hadn’t even scratched at his protruding eyeball!
Next, because it was impossible to coax his eyeball behind his eyelids even after lubricating the globe, an incision was very carefully made at the outer edge of his eyelids to make the hole larger. This allowed us to push the eyeball back into place behind the eyelids.
Now to keep the eyeball in place! Once an eyeball has proptosed it has a tendency to pop out again. This is because the globe is swollen and the eyelids are a little weak. In order to keep the eyeball in place until swelling recedes, a procedure called “temporary tarsorrhaphy” is done. This involves suturing the eyelids shut over the eyeball for a period of time. Stents (little bits of medical rubber tubing) are used to prevent the suture from pulling through the skin. The sutures must be placed very precisely so they don’t rub on the cornea underneath the eyelids.
Ollie was started on medications to prevent infection as well as to reduce swelling and pain. A rigid e-collar (i.e., cone of shame) was placed immediately to prevent Ollie from rubbing at his eye. Ollie has to wear the e-collar continuously until the sutures are finally removed.
Possible complications from proptosis include blindness (especially if the time between injury and correction is prolonged) and increased risk for development of glaucoma, dry eye and corneal changes. Because Ollie still had vision in the injured eye at the time of correction and there was no visible damage to his cornea, prognosis for a full recovery is good.
Since his ocular emergency, Ollie has been doing very well at home; although he’s madder than ever at Turbo! We have already removed one of the sutures — the sutures are removed in stages to help keep the eyeball in place — and Ollie appears to have vision through the slit created. Very soon, once the incision in the outer eyelid has had time to heal, we will remove the second suture and hope Ollie’s eyeball stays put permanently.
Proptosis is only one of many ocular emergencies affecting veterinary patients. While proptosis is a visibly obvious reason to seek veterinary care, other eye emergencies may be more subtle. As a rule of thumb, call your veterinarian right away if your pet has a very red eye or eyes; severe squinting; persisting elevated third eyelid (the fleshy membrane in the inside corner of the eye); noticeably different sized eyeballs; excessive yellow-green discharge; or any other signs of obvious pain or loss of vision.
* Names changed to protect the guilty!