Contributor: Gordon K. Klintworth
Uveitis has many known causes, but the condition is frequently idiopathic. Uveitis may involve the entire uvea or it may be limited to part of it, such as the iris [iritis], ciliary body [cyclitis, pars planitis] or choroid [choroiditis]. Uveitis may be a manifestation of an infection, such as toxoplasmosis, tuberculosis, leptospirosis,  and brucellosis. An infectious uveitis can complicate retinitis caused by Herpes simplex virus or varicella-zoster virus. Uveitis is a manifestation of many systemic inflammatory diseases including spondyloarthropathy, juvelile idiopathic arthritis [arthritis - juvenile idiopathic], inflammatory bowel disease, psoriatic arthritis [arthritis - psoriatic], Behçet disease, Vogt-Koyanagi-Harada disease, sarcoidosis, and multiple sclerosis. Other conditions with uveitis include sympathetic ophthalmia. One variety of uveitis is associated with HLA-B27 [uveitis - HLA-B27 associated]. There is also a strong association of uveitis with HLA-A29. Specific mutations in NOD2 cause an autosomal dominant form of uveitis [Blau syndrome]. Uveitis can be induced by trauma [uveitis - traumatic] as in post-cataract surgery uveitis [uveitis - post-cataract surgery induced]. Uveitis may be unilateral [uveitis - unilateral] or bilateral [uveitis - bilateral]. Complications of uveitis include glaucoma and retinal detachment. Glaucoma is an important common complication of uveitis and is associated with as many as 25% of cases of chronic uveitis. This may be secondary to mechanical obstruction from exudation of inflammatory cells or release of hydrolytic enzymes, prostaglandins, cytokines, and other materials from leukocytes and damaged tissues.