title: Impact of lens case hygiene guidelines on contact lens case contamination.
abstract: OBJECTIVE
  Lens case contamination is a risk factor for microbial keratitis. The effectiveness of manufacturers' lens case cleaning guidelines in limiting microbial contamination has not been evaluated in vivo. This study compared the effectiveness of manufacturers' guidelines and an alternative cleaning regimen.
  
  
  METHODS
  A randomized cross-over clinical trial with two phases (n = 40) was performed. Participants used the lens types of their choice in conjunction with the provided multipurpose solution (containing polyhexamethylene biguanide) for daily wear. In the manufacturers' guideline phase, cases were rinsed with multipurpose solution and air dried. In the alternative regimen phase, cases were rubbed, rinsed with solution, tissue wiped, and air-dried face down. The duration of each phase was 1 month. Lens cases were collected at the end of each phase for microbiological investigation. The levels of microbial contamination were compared, and compliance to both regimens was assessed.
  
  
  RESULTS
  The case contamination rate was 82% (32/39) in the manufacturers' guideline group, compared with 72% (28/39) in the alternative regimen group. There were significantly fewer (p = 0.004) colony forming units (CFU) of bacteria from cases used by following the alternative regimen (CFU range of 0 to 10, and median of 12 CFU per well) compared with that of the manufacturer's guidelines (CFU range of 0 to 10, and median of 28 CFU per well). The compliance level between both guidelines was not significantly different (p > 0.05).
  
  
  CONCLUSIONS
  The alternative guidelines are more effective in eliminating microbial contamination from lens cases than that of the current manufacturer's guideline. Simply incorporating rubbing and tissue-wiping steps in daily case hygiene reduces viable organism contamination.
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia. y.wu@brienholdenvision.org
authors.forename: Yvonne T
authors.initials: YT
authors.lastname: Wu
authors.forename: Yuu Juan
authors.initials: YJ
authors.lastname: Teng
authors.forename: Mary
authors.initials: M
authors.lastname: Nicholas
authors.forename: Najat
authors.initials: N
authors.lastname: Harmis
authors.forename: Hua
authors.initials: H
authors.lastname: Zhu
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
mesh_terms: D000293:Adolescent; D000328:Adult; D018639:Contact Lens Solutions / Q000592:standards*; D003261:Contact Lenses; D018592:Cross-Over Studies; D004866:Equipment Contamination / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006920:Hygiene / Q000592:standards*; D008297:Male; D009517:New South Wales; D010865:Pilot Projects; D017410:Practice Guidelines as Topic; D013997:Time Factors; D055815:Young Adult
chemical_list: D018639:Contact Lens Solutions