Daniele Spaziante

Ultrasonographic biometry of the eyes of healthy adult donkeys

Sixty-two healthy adult donkeys were included in this study, giving a total of 124 eyes for examination. The weight of the donkeys was estimated and an ultrasonography of the eyes was performed using a curvilinear transducer. Ocular measurements were taken in a horizontal plane and included the following values: globe axial length (GAL), anterior chamber depth (ACD), vitreous body depth (VD), lens diameter (LDi) and lens depth (LDe). The mean and sds for each measurement are reported in mm: GAL 34.22±2.05; ACD 3.01±0.58; VD 20.20±1.63; LDi 17.96±1.66 LDe 11.06±0.71. Gender was not a variability factor for ocular biometry in donkeys, while the weight was directly related to the ultrasonographic ocular values. Lens dimensions represented an exception and further investigation should be carried out to verify a possible correlation with age rather than weight. This is the first paper reporting reference data for ocular biometry in donkeys. The ultrasonographic evaluation of the equine eye is a manageable procedure that is easy to perform and can provide information not always obtainable with direct ocular examination. It allows the imaging of intraocular and retrobulbar structures and the diagnosis of some important disorders involving these areas (Scotty and others 2004, Michau 2005, Dietrich 2007). Ocular ultrasound is also indicated where it is impossible to directly visualise (eg, with an ophthalmoscope) posterior structures of the globe in cases of corneal oedema or ulceration, cataract or ocular masses (Withcomb 2002). Ultrasound can be used to investigate enophthalmos, buphthalmos or exophthalmos in cases of ocular protrusion and suspicion of disparity in globe size (Withcomb 2002). The most common diseases that can be detected or confirmed with ultrasound are corneal diseases, cataract, lens luxation, intraocular cysts or masses, glaucoma and retinal detachment (Reef 1998, Withcomb 2002). Although horses and donkeys can be affected by …