Proposed pathogenesis for the delayed postoperative opacification of the hydroview hydrogel intraocular lens

PURPOSE: To report the clinical, histopathologic, ultrastructural, and elemental features of 17 opacified Hydroview (Bausch and Lomb Surgical, Rochester, New York, USA) hydrogel intraocular lenses (IOL) necessitating explantation and discuss from a clinicopathologic perspective why these lenses became opacified. Interventional case series with clinicopathologic correlation. METHODS: Seventeen hydrogel lenses were explanted from 17 different patients owing to decreased visual acuity or quality of vision an average of 29 months after uneventful phacoemulsification and IOL implantation and associated with a granular-appearing opacification superficially within the optic. Lenses were examined by light microscopy, transmission electron microscopy (TEM), and energy dispersion x-ray (EDX) spectroscopy. A control IOL was included in our study. RESULTS: All explanted lenses showed positive staining for calcium by light microscopy. Transmission electron microscopy disclosed electron-dense crystalline deposits in the superficial substance of the IOL optic. Energy dispersion x-ray spectra analyses showed the presence of calcium and phosphorus mainly in the electron-dense periphery of the deposits in all of the specimens and the presence of silicon mainly in the electron-lucent center of the deposits in the majority of the specimens. No positive staining or deposits were observed on the IOL control or in the haptics. CONCLUSIONS: Our study is the first to demonstrate that the calcium deposits are associated with silicon, which was presumably derived from the silicone gasket in the Surefold (Bausch and Lomb Surgical, Rochester, New York, USA) packaging system, manufactured specifically for this IOL. Silicon may act as a nidus for calcium deposition within the lens, which is consistent with our findings. There may be other factors involved, and this important clinical problem requires further study.