title: Protein deposition on a lathe-cut silicone hydrogel contact lens material.
abstract: OBJECTIVE
  To determine the quantity of total protein, total lysozyme, and the conformational state of lysozyme deposited on a novel, lathe-cut silicone hydrogel (SiHy) contact lens material (sifilcon A) after 3 months of wear.
  
  
  METHODS
  Twenty-four subjects completed a prospective, bilateral, daily-wear, 9-month clinical evaluation in which the subjects were fitted with a novel, custom-made, lathe-cut SiHy lens material. The lenses were worn for three consecutive 3-month periods, with lenses being replaced after each period of wear. After 3 months of wear, the lenses from the left eye were collected and assessed for protein analysis. The total protein deposited on the lenses was determined by a modified Bradford assay, total lysozyme using Western blotting and the lysozyme activity was determined using a modified micrococcal assay.
  
  
  RESULTS
  The total protein recovered from the custom-made lenses was 5.3 +/- 2.3 microg/lens and the total lysozyme was 2.4 +/- 1.2 microg/lens. The denatured lysozyme found on the lenses was 1.9 +/- 1.0 microg/lens and the percentage of lysozyme denatured was 80 +/- 10%.
  
  
  CONCLUSIONS
  Even after 3 months of wear, the quantity of protein and the conformational state of lysozyme deposited on these novel lens materials was very similar to that found on similar surface-coated SiHy lenses after 2 to 4 weeks of wear. These results indicate that extended use of the sifilcon A material is not deleterious in terms of the quantity and quality of protein deposited on the lens.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Lakshman N
authors.initials: LN
authors.lastname: Subbaraman
authors.forename: Jill
authors.initials: J
authors.lastname: Woods
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Teichroeb
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D001672:Biocompatible Materials / Q000737:chemistry*; D015153:Blotting, Western; D003263:Contact Lenses, Hydrophilic; D004867:Equipment Design; D005136:Eye Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008297:Male; D008875:Middle Aged; D008968:Molecular Conformation; D009113:Muramidase / Q000032:analysis / Q000737:chemistry; D011446:Prospective Studies; D012828:Silicones; D013997:Time Factors; D055815:Young Adult
chemical_list: D001672:Biocompatible Materials; D005136:Eye Proteins; D012828:Silicones; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D009113:Muramidase