A retrospective clinicopathologic review of 105 cases of sympathetic ophthalmia showed histologic features of prognostic significance and evaluated the role of therapy. Classic descriptions omit retinal changes, but 58.0% of our cases had retinal detachment and 42.2% showed intraretinal inflammation. The optic nerve and/or meninges were inflamed in 51%. Optic atrophy was seen in 54.4%. Plasma cells are said to be characteristically absent, but 65.0% of steroid-treated and 85.7% of cases before the steroid era showed plasma cell infiltration. Severity of inflammation pathologically correlated with final visual outcome, and corticosteroid therapy changed both the character and severity of inflammation. Early enucleation of the exciting eye after onset of symptoms in the fellow eye was found to improve visual prognosis. Electron microscopy performed on fresh tissue and choroidal cell cultures revealed no viral particles, and viral and mycoplasma cultures all proved negative.