Senile scleral plaques: a histopathologic study using energy-dispersive x-ray microanalysis.

The investigators reviewed the pathologic findings of 21 senile scleral plaques in 17 enucleated globes. Eyes were fixed in formalin and routinely processed for light microscopic examination. Two representative calcified scleral plaques were subjected to energy-dispersive x-ray microanalysis. Plaques were located in the sclera just anterior to the insertion of the horizontal rectus muscles. Microscopic examination of the involved sclera disclosed a spectrum of histopathologic changes involving increased hematoxylinophilia of the scleral collagen, decreased stromal cellularity, the presence of scleral fibers with a unique corkscrew appearance, and calcium deposition. The calcified plaques contained calcium phosphate as indicated by histochemical methods and energy-dispersive x-ray microanalysis. Conjunctival elastosis was present in 12 of the 14 eyes in which sufficient conjunctiva was present for histologic evaluation. Accumulated actinic damage from solar irradiation may play a role in the pathogenesis of senile scleral plaques.