Proptosis

Ocular proptosis is the traumatic forward displacement of the globe out of the orbit, most often resulting in the globe being displaced in front of the eyelids.  This is a serious ocular emergency that requires immediate attention to help minimize patient discomfort, damage to the eye, and damage to vision.

Proptosis can occur secondary to acute trauma.  The type and degree of trauma to induce a proptosis can vary depending on the pet and breed.  Sometimes excessive physical restraint or increased pressure around the neck from leash pulling can cause proptosis in brachycephalic (flat-faced) breeds, where little other than the eyelids maintain the globe within the orbit/”socket”.  More trauma is usually required to cause proptosis in non-brachycephalic dogs and cats. In cases of dog-on-dog fight or blunt force injury (hit by car, there may be additional injuries (puncture wounds, fractures) that also require treatment.

Proptosis frequently leads to damage of the globe and associated important structures needed for normal vision.  Many factors are considered when determining the patient’s visual prognosis, which may be improved in cases managed promptly after the inciting trauma.  Prognosis for maintaining a comfortable eye, regardless of visual outcome, depends on several factors.

Negative prognostic indicators include:

• Globe rupture
• Intraocular hemorrhage
• Avulsion of 3 or more extraocular muscles
• Optic nerve avulsion
• Orbit/skull fractures

Treatment includes timely globe replacement and temporary sutures in the eyelids to protect the exposed globe until the orbital swelling resolves. Eyelid sutures are left in place for a minimum of two to three weeks while the damaged tissues heal. Postoperative care with oral and topical broad-spectrum antibiotics, a systemic anti-inflammatory, pain medication, and an Elizabethan collar are commonly required.

Long-term complications of proptosis are common, as the traumatic displacement of the globe can damage the optic nerve, extraocular muscles, and the vascular and nervous supply to the eye. Lateral deviation of the globe (strabismus) is often seen due to avulsion of the muscle in the inner corner of the eye (called the medial rectus muscle).  This deviation can change the appearance of the eye long term and it may be associated with recurrent corneal ulcers due to changes globe position, tear film quality, and sometimes due to poor or reduced blinking ability.  Long term management with medication may be necessary after the injury has healed.

Another treatment option for proptosed globe(s) includes surgical enucleation (removal) of the injured globe, which may be the appropriate option if the patient presents with one or several of the previously listed negative prognostic indicators.

If you have any questions regarding proptosis, please call your Veterinary Ophthalmologist at Eye Care for Animals.