Equine eye diseases should always be taken seriously, as they often require prompt treatment. Traumas to the eye or the region of the eye, pain symptoms associated with the eye (e.g., squinting or holding the eye closed, watery discharge, sensitivity to light), sudden changes in the colour of the surface of the eye or sudden decrease in vision give cause for rapid examination.
At the ophthalmology outpatient clinic of the Equine Hospital, horses undergo thorough eye examinations. These always cover both eyes. An eye examination includes a limited general physical examination, a limited neuro-ophthalmological examination (assessment of responses and reflexes), tonometry, assessment of the surface and interior of the eye (biomicroscopy, ophthalmoscopy), and, when necessary, the collection of, for example, cytological and culture specimens. Most of the examination is carried out with the horse in stocks, and usually sedated, in an examination room with dimmed lighting.
Further examinations may be necessary, including the assessment of vision with a maze test, the assessment of the bone structures in the eye region with contrast X-rays, ocular ultrasonography, the measurement of the refractive error of the eye (retinoscopy), or the measurement of the electrical responses of the retina (electroretinography, ERG).
Horses can contract a number of eye diseases that occur in other animal species as well, but as flight animals they are particularly prone to acute traumas. Because of factors associated with the equine environment, corneal wounds can become inflamed relatively easily, and, at worst, these infections may pose a threat to vision or the preservation of the eye as a whole. In addition, horses are predisposed to immune-mediated eye diseases, which often require long-term care and, at worst, can threaten their vision or the preservation of the eye. The most common of these are immune-mediated keratitis and equine recurrent uveitis, a recurring inflammation of the uvea.
The Equine Hospital has the capacity for intensive round-the-clock pharmacotherapy for eye patients when needed. Depending on individual diagnoses and treatment plans, the therapies available include the following:
At the Equine Hospital, the following people work with eye diseases: