title: Impact of a rub and rinse on solution-induced corneal staining.
abstract: OBJECTIVE
  To investigate whether the inclusion of a rub and rinse step before contact lens disinfection has an impact on solution-induced corneal staining.
  
  
  METHODS
  This was a prospective, double-masked, single investigator study. Twenty participants were recruited for two visits, where balafilcon-A lenses were worn bilaterally for 2 h. Each pair of lenses was prepared using two different methodologies. The "control" lens was transferred from the blister pack directly into a storage case containing polyhexamethylene biguanide-based lens care solution. The contralateral "test" lens was rubbed and simultaneously rinsed using the same polyhexamethylene biguanide-based care solution, for either 60 s (visit 1) or 20 s (visit 2). Both lenses were then soaked in the solution overnight. After baseline corneal staining assessments, the lenses were inserted following a randomized contralateral model. After 2 h, lenses were removed, corneal staining was regraded, and comfort scores were obtained.
  
  
  RESULTS
  Rubbed and rinsed test lenses induced significantly less corneal staining than control lenses for all participants during visit 1 (mean ± SD: 516 ± 843 vs. 2170 ± 902; p < 0.001) and visit 2 (522 ± 417 vs. 2091 ± 965; p < 0.001). There was no significant difference between the test lenses during visits 1 and 2 (p = 0.72) or controls (p = 0.50). Comfort scores did not differ between eyes (p > 0.05).
  
  
  CONCLUSIONS
  Corneal staining induced after 2 h of lens wear with the combination of balafilcon-A and polyhexamethylene biguanide-based lens care solution can be significantly reduced by including a rub and rinse step before overnight soaking. Further work is required to establish the longevity of this effect during the monthly wearing cycle.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Canada ON N2L 3G1. rpeterso@uwaterloo.ca
authors.forename: Rachael C
authors.initials: RC
authors.lastname: Peterson
authors.forename: Desmond
authors.initials: D
authors.lastname: Fonn
authors.forename: Craig A
authors.initials: CA
authors.lastname: Woods
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D001645:Biguanides / Q000009:adverse effects; D018639:Contact Lens Solutions / Q000009:adverse effects*; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000187:drug effects* / Q000473:pathology*; D004202:Disinfectants / Q000009:adverse effects; D004311:Double-Blind Method; D006801:Humans; D020100:Hydrogels; D008405:Massage; D008875:Middle Aged; D011322:Primary Prevention / Q000379:methods*; D012828:Silicones; D013194:Staining and Labeling; D007507:Therapeutic Irrigation; D055815:Young Adult
chemical_list: D001645:Biguanides; D018639:Contact Lens Solutions; D004202:Disinfectants; D020100:Hydrogels; D012828:Silicones; C523195:balafilcon A; C031233:polihexanide