Exophthalmos and Orbital Diseases in Rabbits

Exophthalmos is a condition in which the rabbit's eyeballs are displaced from the orbital cavity or eye socket due to oral diseases or the development of swelling or a growth behind the eye. Typically, the eyeball is pushed forward and away from the socket, but depending on the location of the swelling, the eyeball may displaced in the backward direction on rare occasions.

Young rabbits, dwarf breeds, lop breeds, and middle-aged rabbits are more easily affected by exophthalmus due to a primary tooth or oral disease.

Symptoms and Types

The other main types of orbital disease include:

• Malpositioned eye — caused by changes in volume (loss or gain) of the contents of the eye, or abnormal extraocular muscle function
• Enophthalmos — caused by loss of orbital volume or space-occupying lesions in the front of the globe of the eye
• Strabismus — abnormal movement of eyeballs - is usually caused by improper muscle tone

The symptoms for these orbital diseases will vary but typically include a history of dental disease, incisor overgrowth, nasal discharge, and upper respiratory infection. Other symptoms include:

• Lethargy
• Depression
• Protrusion, drooping of eyelid
• Teeth grinding
• Excessive drooling
• Dropping food out of the mouth
• Facial asymmetry, possibly visible masses in rabbits with tooth root abscesses
• Change in drinking or eating behaviors (e.g., preference for soft foods)
• Hunched posture and an unwillingness to move

Diagnosis

Your veterinarian will perform a thorough physical exam and detailed evaluation on your rabbit to determine the underlying cause. X-rays of the skull and face are always recommended, and your veterinarian may include X-rays of the chest region to look for possible respiratory involvement. Orbital ultrasonography can also be used to give a more detailed image of the extent of the lesion, and computed tomography (CT) can be used for superior visualization of the structures surrounding the eyes.

A detailed oral and nasal examination will be done, with a fluid sample taken by needle aspiration from the orbit for analysis. If a mass is found in the orbital cavity, skull, or elsewhere in the body, a tissue and cell biopsy can be performed to confirm if cancer is present.