Diseases of the Uvea, Uveitis, and Recurrent Uveitis

The uveal tract comprises the iris, ciliary body, and choroid and is anatomically similar to the uveal tract of other species. As in most herbivores, the adult equine pupil is horizontally oval. The blood–ocular barrier limits the immune response to the internal aspects of the eye, causing the eye to be considered an immune-privileged site. With trauma or inflammation, these barriers can be disrupted, allowing blood products and cells to enter the eye. Flare, cell accumulation, or haze in the aqueous or vitreous are clinically observable signs of the disruption of the blood–ocular barrier that occurs in uveitis. Most primary neuroectodermal intraocular neoplasms are congenital, deriving from the primitive neuroectoderm of the optic cup. In clinical patients with signs of uveitis, the clinician must differentiate several clinical diagnoses, including uveitis secondary to corneal disease, trauma, infectious, parasitic, immune-mediated, heterochromic iridocyclitis with keratitis, equine recurrent uveitis, and inflammation associated with neoplasia.