eye disorders
Overview of Uveitis
Introduction
Uveitis is defined as inflammation of the uveal tract—the iris, ciliary body, and choroid. However, the retina and fluid within the anterior chamber and vitreous are often involved as well. About half of cases are idiopathic; identifiable causes include trauma, infection, and systemic diseases, many of which are autoimmune. Symptoms include decreased vision, ocular ache, redness, photophobia, and floaters. Although uveitis is identified clinically, identifying the cause typically requires testing. Treatment depends on cause, but typically includes topical, locally injected, or systemic corticosteroids with a topical cycloplegic-mydriatic drug. Noncorticosteroid immunosuppressive drugs may be used in severe and refractory cases. Uveitis is inflammation of the uveal tract (see figure Cross-section of the eye ). Uveitis is classified anatomically as Anterior uveitis:Localized primarily to the anterior segment of the eye, includes iritis (inflammation in the anterior chamber alone) and iridocyclitis (inflammation in the anterior chamber and anterior vitreous) Intermediate uveitis: Localized to the vitreous cavity and/or pars plana (part of the ciliary body that extends posteriorly beyond the junction of the iris and sclera) Posterior uveitis:Any form of retinitis, choroiditis, or inflammation of the optic disk Panuveitis: Inflammation involving anterior, intermediate, and posterior structures Uveitis is also classified by onset (sudden or insidious), duration (limited or persistent), and course (acute, recurrent, or chronic). The zonules of Zinn keep the lens suspended, and the muscles of the ciliary body focus the lens. The ciliary body also secretes aqueous humor, which fills the anterior and posterior chambers, passes through the pupil into the anterior chamber, and drains primarily via the Schlemm canal. The iris regulates the amount of light entering the eye by adjusting the size of its central opening, the pupil. Visual images are focused on the retina. The conjunctiva covers the eyeball and lines the upper and lower eyelids; it ends at the limbus. The cornea is covered with epithelium that is more sensitive than and differs from the conjunctival epithelium. 