What signs are present in this horse, referred after failing a pre-purchase examination? Can you arrive at a pathological story which links them all together?
The cornea has a white lesion which is most likely to be corneal oedema, there is a widely dilated pupil, a darkened iris and an upwardly luxated lens. These suggest a chronic uveitis with secondary glaucoma and subsequent secondary lens luxation. This histological image shows the iridocorneal angle in a similar case of glaucoma following uveitis, where the drainage angle is being obliterated by inflammatory cells. Amazingly the horse shown in the clinical picture, while having intraocular pressures in the low thirties (in mmHg), still has vision and was ridden by its owner. Problems with insuring the animal rendered it less that fit for sale.