title: Determination of the lysozyme deposit curve in soft contact lenses.
abstract: OBJECTIVE
  To determine lysozyme deposition as a function of time in soft, high-water content, ionic (group IV) contact lenses.
  
  
  METHODS
  ACUVUE lenses were worn on an extended-wear basis (15 minutes, 2 hours, 4 hours, 6 hours, 8 hours, 1 day, 2 day, and so forth, up to 11 consecutive days). New lenses were dispensed at the beginning of each lens-wear period. After each wear cycle, lenses were analyzed for lysozyme deposition by high performance liquid chromatography.
  
  
  RESULTS
  Lysozyme rapidly accumulated on lenses (15 minutes approximately 55 microg/lens) and reached a plateau level by day 6 ( approximately 1300 microg/lens). Most patients in the study showed a plateau range between 1200 and 1400 microg/lens. Six-month and 12-month follow-up studies with ACUVUE lenses showed minimal variation at the 5-day wear time point between the initial, sixth, and 12th month results.
  
  
  CONCLUSIONS
  This study measured the rate of lysozyme buildup on lenses over time and demonstrated that lysozyme levels associated with group IV lenses reached a plateau after approximately 1 week of extended wear. Little variability was seen in lens lysozyme deposition up to 1 year later. The information derived from this study concerning the rate and variability of deposition has implications for the design and interpretation of cleaning studies and contact lens performance evaluations.
authors.affiliation: Alcon Research, Ltd, Fort Worth, TX 76134, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Keith
authors.forename: Mike T
authors.initials: MT
authors.lastname: Christensen
authors.forename: Jacqueline R
authors.initials: JR
authors.lastname: Barry
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Stein
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003262:Contact Lenses, Extended-Wear; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009113:Muramidase / Q000378:metabolism*; D011485:Protein Binding; D013997:Time Factors
chemical_list: D005136:Eye Proteins; D009113:Muramidase