Calcification of intraocular hydrogel lens: evidence of dystrophic calcification

Abstract

To report and describe the surface calcification of three cases of implanted intraocular hydrogel lens. Three surgically extracted hydrogel intraocular lenses were studied by light and transmission electron microscopy as well as by energy dispersion X-ray microanalysis. The lens surfaces were covered by granular deposits of calcium phosphate, clearly delineated by von Kossa and alizarin stains for calcium. Transmission electron microscopy showed the deposits to be located within the superficial lens material to a depth of 7 microm and to be associated with what appear to be traces of cellular material including basement membrane and plasmalemma. To the authors' knowledge there has been only one other transmission electron microscopic study. Energy dispersion X-ray microanalysis showed the deposits to contain calcium and phosphorous in all cases. This study confirms and extends the previous reports of five cases of calcification of hydrogel intraocular lenses. The exact mechanism of calcification remains obscure but evidence suggesting cell-mediated dystrophic calcification of the lens surface is presented. Further study is required to monitor the incidence and development of this phenomenon.