Anterior Uveitis in Small Animals

The anterior uvea consists of the iris, ciliary body, and anterior chamber (or iridocorneal) angle. Anterior uveitis or iridocyclitis is commonly diagnosed in dogs and cats but is observed in other species as well. It may be confused with other inflammatory conditions of the cornea or conjunctiva.

Clinical signs of acute anterior uveitis (see acute anterior uveitis image) include the following:

• blepharospasm

• episcleral or conjunctival hyperemia

• diffuse corneal edema

• miosis

• aqueous flare (indicative of protein or cells in the anterior chamber)

• fibrin in the anterior chamber

• hypopyon

• hyphema

Acute anterior uveitis, cat

Image

Courtesy of UC Davis Comparative Ophthalmology Service.

Chronic anterior uveitis, in addition, may be associated with anterior or posterior synechiae, keratic precipitates, dyscoria or irregular pupil shape, cataracts, and secondary glaucoma.

Intraocular pressure (IOP) is typically low in patients with acute anterior uveitis; however, a normal or elevated IOP may be observed if aqueous drainage is decreased or obstructed by the inflammation.

A fluorescein stain should always be performed to assess for concurrent corneal ulceration.

Anterior uveitis can be caused by other ocular disorders, including blunt or penetrating trauma, cataracts, a neurogenic reflex from corneal ulceration, lens instability, and intraocular neoplasia. Systemic diseases should be suspected, particularly when both eyes are involved. These include infectious and autoimmune diseases and metastatic neoplasia.

Prognosis and treatment depend on the underlying cause.

Regardless of the diagnosis, treatment usually includes the following:

• topical or systemic corticosteroids or NSAIDs

• topical mydriatics

• other drugs to target specific etiologies

Chronic or recurrent anterior uveitis (eg, uveodermatologic syndrome in dogs) is more challenging to manage because of the high likelihood of developing secondary cataracts, glaucoma, or phthisis bulbi.