Pars planitis is a disease of the eye that is characterized by inflammation of the narrowed area (pars plana) between the colored part of the eye (iris) and the choroid. This may lead to blurred vision; dark, floating spots in the vision; and progressive vision loss. As the condition advances, cataracts, retinal detachment, or macular edema (fluid within the retina) may develop. Pars planitis most often affects young men and is generally not associated with any other disease or symptoms (idiopathic); however, it can be associated with other autoimmune conditions such as multiple sclerosis and sarcoidosis. Treatment typically includes corticosteroid drugs, immunosuppressive medications, and/or surgery.

Pars planitis is characterized by inflammation of the narrowed area (pars plana) between the colored part of the eye (iris) and the choroid. This may lead to blurred vision; dark, floating spots in the vision; and progressive vision loss. Approximately 80% of cases are bilateral (affecting both eyes), although one eye is typically more affected than the other. As the condition advances, cataracts, retinal detachment, or macular edema (fluid within the retina) may develop.

Although most cases occur sporadically in people with no family history of the condition, pars planitis can rarely affect more than one family member. In these cases, there may be a genetic component; however, a disease-causing gene and specific inheritance pattern have not been identified.

It is often recommended that people over age 25 with pars planitis have an MRI of their brain and spine to rule out multiple sclerosis.

If medications are not effective, surgery may be considered. Cryotherapy has been performed in affected people to remove eye tissue that has inflammation. Although this surgery has been shown to be effective in restoring clarity of vision, there are concerns that it may cause damage to other parts of the eye. Another surgery, known as vitrectomy, can be done to remove cloudy fluid (vitreous humor) from the eye.