Anterior uveitis or iridocyclitis is most common in dogs, cats, and horses but is uncommon in other species. It is often confused with other inflammatory conditions of the cornea and/or conjunctiva. It presents clinically as acute photophobia, pain, blepharospasm, a congested and red conjunctiva, corneal edema, reduced intraocular pressure, miosis, aqueous flare (increased levels of proteins and inflammatory cells in the aqueous humor) to frank hypopyon, and/or hyphema. Chronic anterior uveitis, in addition, may exhibit anterior and posterior synechiae, irregular pupil shape, cataract formation, and secondary glaucoma associated with peripheral anterior synechiae and/or annular posterior synechiae and iris bombé.
Anterior uveitis may be associated with trauma, systematic diseases (especially when bilateral), cataract formation, primary and metastatic neoplasia, and other causes. Prognosis and therapy depends on the cause. Therapy usually includes mydriatics, topical and systemic antibiotics, corticosteroids or NSAIDs, and other drugs to target specific pathogens. Prognosis is usually favorable for acute anterior uveitis but guarded for recurrent or chronic anterior uveitis (eg, uveodermatologic syndrome in dogs, Golden Retriever uveitis, or equine recurrent uveitis) because of the high likelihood of developing secondary cataracts, refractory glaucoma, and phthisis bulbus.