Retrobulbar Diseases in Dogs and Cats

Retrobulbar disease is frequently observed in veterinary medicine. The orbit is in close vicinity to the oral and nasal cavities, teeth, paranasal sinuses and salivary glands. Therefore, any diseases from these nearby structures can affect the orbit and globe.

There are no specific clinical signs that may help point to the aetiology of retrobulbar diseases.  Depending on the location of the disease, the globe can be exophthalmic, enophthalmic, or deviated laterally, medially, dorsally, or ventrally, with or without protrusion of the nictitans membrane. On clinical examination, the affected eye may have reduced retropulsion upon palpation, hyperemia of the conjunctiva, dessication of the cornea due to improper blinking, and/or corneal ulceration.  There may be a mild increase in intraocular pressure, due to external compression of the globe.  In some cases, blindness can be observed, due to compression onto the optic nerve.

Ancillary diagnostic tests might include orbital ultrasound, either through the globe or transorally, CT scan, or MRI.  In some cases, if the lesion can be clearly delineated via imaging and is easily accessible without damaging nearby vital structures, fine needle aspiration is performed.  These tests help define the origin of the lesion, the extent of the lesion, as well as the aetiology of the lesion.

Treatment of retrobulbar disease will vary on the aetiology of the underlying condition. If the cause is inflammatory or infectious, systemic broad spectrum antibiotics and nonsteroidal anti-inflammatory medications, with or without topical antibiotics and lubricant for the cornea, may resolve the condition. If the inflammatory or infectious condition is related to periodontitis, extraction of affected teeth and dental cleaning, in addition to antibiotic and anti-inflammatory therapy, are indicated. In some cases, drainage of the area caudal to the last upper molar should be considered. However, utmost care must be exercised to ensure the extraconal and intraconal structures are not damaged.  If the retrobulbar disease is related to salivary retention cyst or mucocele, surgical excision of the cystic cavity and associated gland should be considered.

Retrobulbar neoplasia generally carries a guarded prognosis. In some cases, especially where the neoplasia is solitary and has not caused any nearby bone destruction, enucleation and complete exenteration of the orbit can be considered. Radiotherapy (if available) with or without adjunctive chemotherapy are also effective treatment for some types of retrobulbar neoplasia. 

Dr. Derek Wai Yee Chow

(Ophthalmology)
BVSc (HONS), DACVO, DAiCVO, MANZCVS, MRCVS Specialist in Veterinary Ophthalmology

Diplomate of the American College of Veterinary Ophthalmologists

Diplomate of the Asian College of Veterinary Ophthalmologists

 

Dr. Derek Wai Yee CHOW

Dr. Chow graduated from University of Queensland, Australia. He developed a strong interest in Veterinary Ophthalmology whilst working as a general practitioner in Hong Kong. He gained valuable knowledge and skills in veterinary ophthalmology by spending time with various veterinary ophthalmologists in Australia. Dr. Chow is a member of the Australian College of Veterinary Scientists and the Royal College of Veterinary Surgeon. He is a Diplomate of the American and Asian College of Veterinary Specialists. He is the only Veterinary Ophthalmologists that has specialty recognition in both Asia and North America.

 

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