Dexamethasone‐induced exophthalmos in a group of Holstein calves

Abstract

Six Holstein calves were evaluated for progressive exophthalmos. The affected calves were receiving daily injections of dexamethasone (30 microg/kg subcutaneously twice daily) as part of a metabolic study. The control calves did not exhibit exophthalmos. The ocular examinations were normal except for the exophthalmos, which ranged from mild to marked in severity. Upon postmortem examination, marked deposition of retrobulbar adipose tissue was noted in the affected calves. Dexamethasone administration appears to increase deposition of retrobulbar adipose tissue resulting in a progressive exophthalmos.

The Exophthalmos of Eyes as An Unusual and Unregistered Sign of Mycoplasma wenyonii Infection in Newborn Calves in Basrah, Iraq

“…It has been documented that, exophthalmos is a common clinical sign of some diseases, which may be accompanied sometimes by deviation of the globe, third eyelid prolapse, a widened palpebral fissure, conjunctival swelling/edema/chemosis, epiphora, and a decreased ability to blink and subsequent exposure keratopathy (also known as exposure keratitis). Moreover, Retrobulbar tumors of dogs and cats had exophthalmos, with conjunctival hyperemia, fundic abnormalities [11]. On the other hand, exophthalmos is described as "the anterior displacement of a normal-sized globe within the orbit and most easily identified by viewing the head from the front and comparing the angle of eyelashes, the relative prominence of the globe, and the size of the palpebral fissure.…”

Cavernous sinus syndrome in a holstein bull

“…Recent work suggests that these changes may be due to a defect in the motor nucleus of the abducent nerve . Exophthalmos has also occurred as a result of retrobulbar fat deposition after daily dexamethasone injections in calves . Other causes of unilateral exophthalmia in cattle are generally due to space occupying lesions due to inflammation or neoplasia, most commonly retrobulbar lymphosarcoma .…”