Morphological variation of Dalén-Fuchs nodules in sympathetic ophthalmia.

Fifty cases of sympathetic ophthalmia were examined histologically to determine the incidence and morphology of Dalén-Fuchs nodules. At least one well-defined Dalén-Fuchs nodule was identified in 18 (36%) of the eyes examined. Three types of lesions at the level of the retinal pigment epithelium were recognised. One type was found to consist of focal hyperplasia and aggregation of retinal pigment epithelial cells. A second type, classically referred to as Dalén-Fuchs nodules, consisted of epithelioid cells and lymphocytes covered by an intact dome of retinal pigment epithelium. The third type of lesion was characterised by degeneration of the overlying retinal pigment epithelium leading to disorganisation of the Dalén-Fuchs nodule and possible release of their contents into the subretinal space. Our study demonstrated that Dalén-Fuchs nodules in sympathetic ophthalmia vary in their morphological appearance as determined by light microscopy.