title: The impact of contact lens care solutions on the thickness of the tear film and contact lens.
abstract: OBJECTIVE
  To determine the impact of compositional differences in contact lens care solutions on the thickness of the tear film during contact lens wear.
  
  
  METHODS
  A randomized, crossover, investigator-masked clinical trial was conducted to compare AMO's Complete MoisturePlus to Alcon's Opti-Free Express in 31 subjects. The primary outcome of this study was a comparison of prelens tear film (PLTF) and postlens tear film (PoLTF) thickness values obtained during the first 2 hours of etafilcon A hydrogel lens wear. Each solution was used by each participant for a period of 7 days, separated by a washout period of 1 day. Alternative outcomes studied included prelens tear film thinning rates, solution preference, and dry eye-related symptom scores. Tear film thickness measurements were made using a noninvasive wavelength-dependent interferometric system.
  
  
  RESULTS
  The average overall PLTF thickness over the 120-minute time period after using Complete MoisturePlus was 3.02 +/- 1.07 microm, whereas the average overall PLTF thickness in this same time interval after using Opti-Free Express was 2.72 +/- 0.86 (P = 0.003). For both solutions, the PLTF could be fitted by the sum of an exponential decay plus a constant. The PLTF decay amplitudes did not statistically differ when the solutions were compared (P = 0.11). There was no difference in overall PoLTF thicknesses when the average values after using each solution were compared (P = 0.57), although there was a difference immediately after the lens was applied to the eye (Complete MoisturePlus average = 4.10 versus Opti-Free Express average = 3.48, P = 0.02). The PoLTF also demonstrated an exponential decay for both solutions. The PoLTF decay amplitudes did not statistically differ (P = 0.14). Twenty subjects (64.5%) preferred Complete MoisturePlus to Opti-Free Express (35.5%) (P = 0.11), and nearly every subject (90.3%) suggested "comfort" as their reason for preference.
  
  
  CONCLUSIONS
  Complete MoisturePlus is associated with a thicker PLTF when compared with Opti-Free Express in contact lens wearers without dry eye symptoms, especially during the first 5 minutes following lens insertion.
authors.affiliation: College of Optometry, The Ohio State University, Columbus, OH 43218-2342, USA.
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Nichols
authors.forename: G Lynn
authors.initials: GL
authors.lastname: Mitchell
authors.forename: P Ewen
authors.initials: PE
authors.lastname: King-Smith
mesh_terms: D000328:Adult; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003263:Contact Lenses, Hydrophilic; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007368:Interferometry; D008027:Light; D008297:Male; D013666:Tears / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018639:Contact Lens Solutions