title: A 1-year prospective clinical trial of balafilcon a (PureVision) silicone-hydrogel contact lenses used on a 30-day continuous wear schedule.
abstract: OBJECTIVE
  To evaluate silicone-hydrogel balafilcon A (PureVision, Bausch & Lomb Inc., Rochester, NY) contact lenses worn on a 30-day continuous wear basis when compared with a traditional hydrogel (Acuvue, Vistakon, Johnson and Johnson Vision Products, Inc., Jacksonville, FL) worn on a 7-day extended wear schedule.
  
  
  METHODS
  Prospective, comparative, paired-eye, interventional, multicenter clinical trial.
  
  
  METHODS
  Two hundred twelve ametropes with no significant ocular pathology.
  
  
  METHODS
  Subjects with normal ocular health who conformed to a set of standard criteria were monitored at seven different sites around the globe. Subjects wore both study lenses simultaneously, one on each eye. Lenses were assigned to right and left eyes according to a randomized schedule. The silicone hydrogel was removed and replaced every month and the traditional hydrogel was removed every 7 days and replaced at 14-day intervals. Subjects were followed for up to 1 year with discontinuation on indication divided between lens-related causes, unrelated factors, and loss to follow-up.
  
  
  METHODS
  Discontinuations, symptoms, vision, lens fit, lens surface assessment, slit-lamp assessment, and patient preferences.
  
  
  RESULTS
  One hundred twenty three subjects completed the 12-month wearing period. There were no vision-threatening events with either lens type. The silicone-hydrogel lenses showed statistically superior performance in physiologic terms with regard to epithelial microcysts, striae, corneal staining, limbal injection, and bulbar injection. Inflammatory reactions, such as corneal infiltrates and tarsal conjunctival abnormalities occurred at similar rates between the lens types. Visible deposition and postlens debris with associated transient corneal indentation were significantly lower with the traditional hydrogel material at specific time points in the study. Visual acuity was comparable with the two lens types. Subjects rated the silicone-hydrogel material as preferable on subjective scales of dryness, comfort, and lens handling. Overall subjective performance was rated superior with the silicone-hydrogel material.
  
  
  CONCLUSIONS
  The high oxygen performance of the silicone-hydrogel lenses provides a superior physiologic environment compared with a traditional hydrogel material during continuous wear. Despite the slightly higher levels of visible deposit on the silicone-hydrogels, superior subjective responses suggest that the plasma coating technology on these lenses is effective in providing comfortable lens wear. The results look promising for the success of silicone-hydrogels as the material of choice for continuous wear contact lenses.
authors.affiliation: Brennan Consultants Pty. Ltd., Melbourne, Australia.
authors.forename: Noel A
authors.initials: NA
authors.lastname: Brennan
authors.forename: M L Chantal
authors.initials: ML
authors.lastname: Coles
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Comstock
authors.forename: Brian
authors.initials: B
authors.lastname: Levy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003262:Contact Lenses, Extended-Wear; D003315:Cornea / Q000502:physiology; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011446:Prospective Studies; D017755:Prosthesis Fitting; D012030:Refractive Errors / Q000628:therapy*; D012826:Silicone Elastomers; D014785:Vision, Ocular / Q000502:physiology
chemical_list: D012826:Silicone Elastomers; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate