Iris bombé in the Equine Patient: An Ultrasono Graphic Evaluation

Uveitis or inflammation of the uvea (including iris, corpus ciliare and chorioidea) is frequently encountered in the equine ophthalmologic patient. Iris bombé is described as forward bulging of the peripheral part of the iris due to posterior synechia to the anterior lens capsule indicating an abnormal flow of the posterior eye chamber fluid. In humans and dogs, iris bombe has been seen with for example uveitis, glaucoma and iridial cysts. This study was performed to clinically and ultrasonographically identify causes and concurrent findings with iris bombé in the equine patient.

The medical records and ultrasound studies of the equine ophthalmologic patients in the period from December 2010 to December 2011 were retrospectively evaluated. The clinical and ultrasonographic findings of the patients with iris bombé were recorded and compared with findings previously recorded in humans and dogs.

A total of 49 equine ophthalmologic patients underwent ultrasonographic examination during this year. There were 6 patients with iris bombé including 3 with equine recurrent uveitis(ERU), 2 with traumatic uveitis and 1 with uveitis of possible traumatic origin. Cornea edema, synechia anterior, synechia posterior, iris prolaps, severe miosis, swelling of the iris, lens cataract, debris in the anterior eye chamber and corpus vitreum, phthisis, minimal buphthalmos, and retinal detachment were ultrasonographic findings in these patients. Ocular pressure was not significantly increased in any of the 6 patients with iris bombé. Enucleation was performed in the 2 patients with traumatic uveitis and 1 one with ERU. Iris bombe resolved after medical treatment in the remaining patients.

Iris bombé was seen in patients with ERU and traumatic uveitis. Concurrent glaucoma as seen in humans was not detected. Synechia anterior was seen in traumatic uveitis patients. Iris bombé should be considered as one of the clinical and ultrasonographic entities in equine uveitis.