title: In vitro and in vivo effects of a lubricant in a contact lens solution.
abstract: OBJECTIVE
  Physical properties and tear film function were investigated for a multipurpose contact lens solution containing the ocular lubricant hydroxypropyl methylcellulose (HPMC).
  
  
  METHODS
  In the laboratory, wetting properties of multipurpose solutions with and without HPMC, and binding of HPMC to hydrogel lenses in vitro following an overnight soak, were measured. Tear physiology was evaluated in 35 hydrogel contact lens wearers using multipurpose solutions with and without HPMC. Pre-lens tear evaporation rate (TER), tear thinning time (TTT) and tear film structure (TFS) were recorded, and subjective responses were obtained.
  
  
  RESULTS
  Laboratory measurements indicated improved wetting with the HPMC-containing solution, and continued release of HPMC from lenses after an overnight soak in the solution. Pre-lens TTT was longer (p < 0.001) and pre-lens TFS was improved (p = 0.034) with use of the HPMC-containing solution. Pre-lens TER and subjective comparisons did not demonstrate significant differences.
  
  
  CONCLUSIONS
  In vitro and in vivo results are consistent with HPMC producing a thicker, longer-lasting layer of fluid on the hydrogel lens, leading to improvements in tear function in contact lens wearers.
authors.affiliation: Department of Vision Sciences, Glasgow Caledonian University, UK.
authors.forename: Lee C
authors.initials: LC
authors.lastname: Thai
authors.forename: Alan
authors.initials: A
authors.lastname: Tomlinson
authors.forename: Peter A
authors.initials: PA
authors.lastname: Simmons
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D018639:Contact Lens Solutions; D003263:Contact Lenses, Hydrophilic; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D065347:Hypromellose Derivatives; D008153:Lubrication; D008297:Male; D008747:Methylcellulose / Q000031:analogs & derivatives*; D013666:Tears / Q000502:physiology*; D013997:Time Factors; D017155:Wettability
chemical_list: D018639:Contact Lens Solutions; D065347:Hypromellose Derivatives; D008747:Methylcellulose