Dystrophic calcification of an implanted hydroxyethylmethacrylate intraocular lens

Hydroxyethylmethacrylate is a biomaterial still under clinical trial for use in foldable intraocular lenses. We observed a patient in whom a geographic opacification developed within an implanted hydroxyethylmethacrylate lens, together with granular deposits on the posterior lens capsule and in the scar of a paracentesis. The intraocular lens and posterior lens capsule were removed because of impaired visual acuity. Light and scanning electron microscopy disclosed nodular calcifications within the intraocular lens and granular, partially crystalline, calcifications on the posterior lens capsule. Energy-dispersive x-ray analysis and x-ray diffraction showed the deposits in the intraocular lens to consist of calcium hydroxyapatite. We presume this mineralization to be dystrophic, with calcium derived from lens remnants and phosphorus possibly derived from a thymoxamine solution used briefly during the cataract operation. Our observation suggests caution in the use of phosphated solutions together with hydroxyethylmethacrylate intraocular lenses and may warrant reconsideration of the suitability of hydroxyethylmethacrylate intraocular lenses, should additional similar cases be reported.