title: Proposed pathogenesis for the delayed postoperative opacification of the hydroview hydrogel intraocular lens.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Ophthalmology, University of Ottawa Eye Institute, Ontario, Canada.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Dorey
authors.forename: Seymour
authors.initials: S
authors.lastname: Brownstein
authors.forename: Vivian E
authors.initials: VE
authors.lastname: Hill
authors.forename: Benjamin
authors.initials: B
authors.lastname: Mathew
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Botton
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kertes
authors.forename: Sherif
authors.initials: S
authors.lastname: El-Defrawy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials / Q000009:adverse effects*; D002114:Calcinosis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D020878:Device Removal; D004577:Electron Probe Microanalysis; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular / Q000009:adverse effects*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D018918:Phacoemulsification; D010758:Phosphorus / Q000378:metabolism; D011102:Polyhydroxyethyl Methacrylate / Q000009:adverse effects*; D019064:Product Packaging; D011475:Prosthesis Failure; D012086:Reoperation; D012828:Silicones / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D012828:Silicones; D011102:Polyhydroxyethyl Methacrylate; D010758:Phosphorus; D002118:Calcium