title: In vitro contact angle analysis and physical properties of blister pack solutions of daily disposable contact lenses.
abstract: OBJECTIVE
  The purpose of this study was to measure the advancing and receding contact angles (CAs) of five daily disposable (DD) lenses and the osmolality, surface tension (ST), and pH of each blister pack solution.
  
  
  METHODS
  The advancing and receding CAs were measured directly out of the blister pack for five DD lenses: omafilcon A (CooperVision), nelfilcon A (CIBA Vision), modified nelfilcon A (CIBA Vision), etafilcon A (Johnson & Johnson), and narafilcon A (Johnson & Johnson). Advancing CAs were measured using sessile drop and Wilhelmy balance methods. Receding CAs were measured using the Wilhelmy balance method. ST, pH, and osmolality were measured for each blister pack solution from all the DD lenses.
  
  
  RESULTS
  The advancing CAs for the nelfilcon A lenses were statistically lower (P<0.05) than the advancing CAs of the other three lenses. The receding CAs for etafilcon A were statistically lower (P<0.05) than the receding CAs for the other four lenses. The pH of all the blister pack solutions was relatively neutral (7.01-7.43). The ST of the blister pack solution for the modified nelfilcon A was significantly lower (P<0.05) than the ST of all other blister pack solutions. The osmolality of the blister pack solutions for the etafilcon A and narafilcon A lenses were significantly higher (P<0.05) than the other blister pack solutions.
  
  
  CONCLUSIONS
  The modified nelfilcon A lens had low advancing CAs and low receding CAs showing minimal hysteresis. The blister pack solution for the modified nelfilcon A lens had the lowest ST, a low osmolality, and a neutral pH.
authors.affiliation: Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada. klmenzie@uwaterloo.ca
authors.forename: Kara L
authors.initials: KL
authors.lastname: Menzies
authors.forename: Ronan
authors.initials: R
authors.lastname: Rogers
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D018639:Contact Lens Solutions / Q000737:chemistry*; D003261:Contact Lenses; D004209:Disposable Equipment; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D013500:Surface Tension
chemical_list: D018639:Contact Lens Solutions