One hundred cases of clinically acceptable sympathetic ophthalmia (SO) were evaluated histologically to determine the incidence of atypical features and correlate them with the severity of choroidal inflammation. The inflammatory response in the choroid varied from a focal non-granulomatous to a diffuse non-necrotizing granulomatous process. The choriocapillaris was focally involved rather frequently (in 40% of the cases). This was associated with severe inflammation. Chorioretinal adhesions were noted in 7% of the cases. Retinal detachment was observed in 50% of the cases, and this was associated with severe uveal inflammation. Fifty percent of the cases showed retinal perivasculitis and 18% a mild inflammatory infiltrate of the retina. Involvement of the meninges (a finding present in 22% of the cases) and severe inflammation in the scleral canals were both related to the severity of choroidal inflammation. Lens-induced endophthalmitis was observed in 14 cases and was not associated with the severity of the choroidal inflammation. Our observations indicate that the changes interpreted as atypical in SO are usually associated with severe choroidal inflammation, suggesting that these features may be the response to high doses of antigenic agent. The classical histopathologic description of SO may represent only one manifestation of the pathologic response of this disease.