Ultrasonographic examination of the painful equine eye

Ultrasonography is a non-invasive diagnostic procedure that can be used to examine the equineoptic globe, orbit and periocular tissues. In particular, ultrasonographic examination can providevaluable information that cannot be obtained by direct visualisation or the use of other diagnostictechniques when periocular swelling or opacity of the ocular media is present. Ultrasonography is alsouseful for assessing globe size and position. Given the location of the eye, the procedure is usuallysimple to perform and a systematic examination can be undertaken quickly, producing good-qualityimages. However, an understanding of the normal sonographic appearance of the ocular and orbitaltissues is of paramount importance to facilitate image interpretation. Painful conditions of the equineeye are encountered commonly in veterinary practice and ocular ultrasonography can be performedwithout the need for specialist equipment in a field or hospital setting, and findings can facilitateselection of appropriate treatment and allow meaningful prognostication. This article describes how tocarry out ocular ultrasonography and discusses image interpretation, with particular reference to horsespresenting with ocular pain.