However, most patients eventually require additional potent immunosuppressive drugs such as cyclosporine or chlorambucil, both to control the inflammation and to avoid the serious complications of long-term corticosteroid treatment. Pars planitis refers to idiopathic intermediate uveitis and is the most common form of intermediate uveitis. Symptoms and signs are as described above for intermediate uveitis and include floaters, which are due to cells in the vitreous humor or to leakage of fluid from retinal vessels in the perifoveal macular area, called cystoid macular edema. Exudate and condensed vitreous in the pars plana region may have a classic snowbank appearance. Treatment typically includes topical and local corticosteroids, although particularly severe or chronic cases may require cryotherapy or vitrectomy.
Toxoplasmosis is the most common cause of retinitis in immunocompetent patients.
The vast majority of cases are transmitted congenitally, although acquired cases do occur, particularly in patients exposed to cats or to raw or undercooked meat. Symptoms of floaters and decreased vision may be due to cells in the vitreous humor or to retinal lesions or scars. Concurrent anterior segment involvement can occur, with pain, redness, and photophobia. Treatment is required in patients with posterior lesions that threaten vital visual structures, such as the optic nerve or macula, and in immunocompromised patients. Congenital infections are much rarer but may occur.