Equine ocular ultrasonography

Equine ocular ultrasonography (EOUS) provides a complete image of globe structures, regardless of opacities in the ocular media and eyelid swelling. Ultrasonography in veterinary medicine is a very useful diagnostic tool for many other ophthalmic conditions such as enophthalmos, buphthalmos, or exophthalmos, ocular protrusion, and suspected disparity in eyeball sizes. EOUS is usually conducted on the standing horse. In a standard EOUS scan, the iris and ciliary bodies appear as a single irregular hyperechoic structure extending from the periphery to the center, posterior to the anterior chamber and lateral to the crystalline lens. In cases of cataract, EOUS is helpful when corneal edema or other opacities prevent a standard eye examination. Lens rupture is usually secondary to uveitis or trauma. EOUS visualizes breakage in the echoic lens line. Eyelid edema occurs frequently in horses and is generally secondary to eye disease or trauma.