title: Intraoperative crystallization on the intraocular lens surface.
abstract: OBJECTIVE
  To report a physician survey, laboratory studies, and clinical observations of intraoperative crystallization on the surface of the intraocular lens (IOL).
  
  
  METHODS
  We sent a survey to all ophthalmologists in the states of Wyoming, Idaho, Montana, Utah, and Colorado asking whether crystallization on the IOL surface had occurred in any of their patients and what viscoelastics, IOLs, and other solutions were used. All returned surveys were tabulated and analyzed by standard statistical means. A sample of crystallization from an IOL on a glass slide submitted by a physician was analyzed to ascertain the relative elemental composition. During in vitro laboratory studies, BSS Plus (Alcon Surgical, Fort Worth, Texas) and BSS (Alcon Surgical) were measured and analyzed for precipitation. Healon GV (Pharmacia/Upjohn, Kalamazoo, Michigan) and calcium chloride were combined in various solutions and examined for precipitate formation. Silicone IOLs and plate silicone were placed in different BSS and BSS Plus solutions with different viscoelastics and varying calcium concentrations. In seven patients, prominent crystallization on an IOL surface was examined, photographed, and followed for up to 3 years.
  
  
  RESULTS
  Two hundred six surveyed ophthalmologists returned 181 surveys (88%) and reported 29,609 cataract surgeries, with IOL implantation with 22 eyes (0.07%) (22 patients) in which intraoperative crystallization was observed on the IOL surface during 1993. The survey indicated there was a correlation with BSS Plus (chi-square = 4.9, P = .0268) and silicone IOLs (chi-square = 6.8, P = .0093). The sample showed the cation to be calcium.
  
  
  CONCLUSIONS
  Crystallization on the IOL surface during cataract surgery is a rare occurrence that may be associated with calcium as the cation related to an osmotic gradient around the IOL with increased calcium concentration. If encountered surgically, the lens should be exchanged in the operating theater after irrigating the anterior chamber with BSS and completely filling the capsular bag with a low molecular weight viscoelastic.
authors.affiliation: Department of Ophthalmology, University of Utah Health Sciences Center, Salt Lake City, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Olson
authors.forename: K D
authors.initials: KD
authors.lastname: Caldwell
authors.forename: A S
authors.initials: AS
authors.lastname: Crandall
authors.forename: M K
authors.initials: MK
authors.lastname: Jensen
authors.forename: S C
authors.initials: SC
authors.lastname: Huang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium; D002387:Cataract Extraction / Q000009:adverse effects*; D011232:Chemical Precipitation; D003460:Crystallization; D003625:Data Collection; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000453:epidemiology* / Q000473:pathology; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D015205:Northwestern United States / Q000453:epidemiology; D019904:Polymethyl Methacrylate; D012307:Risk Factors; D012826:Silicone Elastomers; D015206:Southwestern United States / Q000453:epidemiology
chemical_list: D012826:Silicone Elastomers; D019904:Polymethyl Methacrylate; D002118:Calcium