title: In vitro comparison of glistening formation among hydrophobic acrylic intraocular lenses(1).
abstract: OBJECTIVE
  To compare glistening formation induced by temperature stressing in vitro among hydrophobic acrylic intraocular lenses (IOLs) available in the United States.
  
  
  METHODS
  John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.
  
  
  METHODS
  Wagon Wheel (WW) packaged 1-piece AcrySof IOLs (Alcon), WW-packaged 3-piece AcrySof IOLs, and Sensar IOLs (Allergan Medical Optics) were analyzed in vitro for 5 consecutive days. Ten IOLs of each type were inserted into viewing chambers filled with balanced salt solution, maintained at 37 degrees C, and evaluated every 24 hours at 37 degrees C and then, after a 2-hour cooling, at room temperature. The IOLs were examined by slitlamp to quantify glistenings and by digital photography to determine glistening size.
  
  
  RESULTS
  The glistening quantity was minimal and did not differ among IOL types at 37 degrees C. The glistenings were smallest in the 1-piece AcrySof IOLs (P <.001): 6.3 microm versus 11.5 microm in the Sensar and 13.4 microm in the 3-piece AcrySof. Upon cooling, the glistening quantity increased dramatically in the 1-piece AcrySof IOLs (P <.008) and was the highest among the IOL types at room temperature (P <.001). The mean glistening size was 7.7 microm. The 3-piece AcrySof IOLs showed a significant decrease in slitlamp-countable glistenings but acquired a dense haze seen as minute glistenings (4.0 microm) at x80 magnification. The glistening quantity in the Sensar IOLs was fairly stable upon cooling; a statistical increase was seen on the last day (P =.007). Cooling nearly doubled the size of the Sensar glistenings, which were the largest at room temperature, 21.7 microm (P <.001).
  
  
  CONCLUSIONS
  Glistening quantity varied among hydrophobic acrylic IOLs and was temperature dependent. Sensar IOLs were more stable than the 2 other IOL types. The glistening phenomenon must be studied further to eliminate the problem.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
authors.forename: Ninel Z
authors.initials: NZ
authors.lastname: Gregori
authors.forename: Terrence S
authors.initials: TS
authors.lastname: Spencer
authors.forename: Nick
authors.initials: N
authors.lastname: Mamalis
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Olson
mesh_terms: D000180:Acrylic Resins; D003080:Cold Temperature / Q000009:adverse effects*; D057927:Hydrophobic and Hydrophilic Interactions; D066298:In Vitro Techniques; D007910:Lenses, Intraocular; D011475:Prosthesis Failure; D013314:Stress, Mechanical
chemical_list: D000180:Acrylic Resins