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Immune-mediated disorders of the equine eye: part 1 – the cornea

02 November 2020
16 mins read
Volume 4 · Issue 6
Figure 3. Chronic deep/mid-stromal immune-mediated keratopathy. Diffuse corneal oedema with grey cellular infiltration and stromal lacunae of green/orange tinged fluid.
Figure 3. Chronic deep/mid-stromal immune-mediated keratopathy. Diffuse corneal oedema with grey cellular infiltration and stromal lacunae of green/orange tinged fluid.

Abstract

Despite the immune-privileged status of the eye, immune-mediated ophthalmic disorders are reasonably common in many species, including the horse. This article (the first of two) discusses those most clinically relevant to the horse and provides practical and up-to-date advice for case management. In all cases, accurate and early identification of the specific disease process occurring is essential to achieving the best outcome for the patient. Quick fixes are rare, and the focus should always be on outlining a clear treatment and management strategy from the outset, to ensure client compliance with what is often a frustrating and difficult process.

The eye has long been recognised as an immuneprivileged organ, whereby immune responses to foreign antigens are suppressed or inhibited. This allows the preservation of normal function within such a highly specialised organ. Immune privilege is maintained by both structural barriers and a complex array of active homeostatic mechanisms. Despite ocular immune privilege, immune-mediated diseases of the eye are very common in many species, for example age-related macular degeneration in people. This is the first of two articles on immune-mediated diseases of the equine eye and will focus on the cornea, with the second article discussing the uveal tract. In both cases, the emphasis will be on the practicalities of treatment and long-term management. A collaborative approach between owner and veterinary surgeon is usually essential from an early stage with immune-mediated disorders, as making owners aware of the potentially progressive and recurrent nature helps to maximise adherence to treatment regimens that are often difficult and frustrating.

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