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Exophthalmos versus buphthalmos in dogs and cats | VETgirl Veterinary Continuing Education Videos

In today’s VETgirl online veterinary continuing education video, we discuss the difference between exophthalmos and buphthalmos in the dog or cat. When a patient is presented with what the owners perceive is a bulgy eye, it is the veterinarian’s job to determine the underlying cause. There are 2 main causes of a “bulged” eye: exophthalmos and buphthalmos. Exophthalmos is a normal sized eye which is being pushed out of the orbit. Buphthalmos is an enlarged globe.

VETgirl’s tip on how to differentiate exophthalmos and buphthalmos?

With exophthalmos, the third eyelid should also be protruding. Exophthalmos is caused by a space-occupying orbital lesion such as cellulitis, abscess, or neoplasia and these lesions will also push the 3rd eyelid out of the eye socket. Generally, these eyes are still visual, have a pupillary light response (PLR), and the intraocular exam should be fairly unremarkable. Retropulsion is dramatically reduced, and may be very painful if infection is present. If exophthalmos is present, a thorough oral exam should be completed, paying close attention to the gingiva caudal to the last upper premolar. This area is in close proximity to the orbit, and tooth root infections or foreign bodies can often be present. Additional imaging techniques for the orbital tissues include ocular ultrasound and/ or CT scan.

In comparison, buphthalmos is only caused by chronic glaucoma. Buphthalmic eyes are notably larger than the contralateral eye (you can use a Schirmer tear test and measure the horizontal corneal diameter if you need!). These eyes are always blind, will lack a PLR, and often have chronic changes to the cornea and lens (e.g., like edema, vascularization, cataract, lens luxation, etc.).

In this VETgirl video, this patient presented with exophthalmos and facial pain. Under sedation, a thorough oral cavity examination was performed and foreign material (e.g., grass) was found protruding from the gingiva. The wound was enlarged and multiple pieces of organic debris were removed. For this reason, following the sedated examination and vigorous flushing, this patient received a course of oral, broad spectrum antibiotics to treat the cellulitis. In addition, oral non-steroidal anti-inflammatory drugs and pain medications can be used, and often are of great benefit.

Finally, make sure your patient can fully blink over the exophthalmic or buphthamic globe. Gel lubricants or ointments should be prescribed if an incomplete blink is present. Protect that eye!

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