title: A pre-application drop containing carboxymethylcellulose can reduce multipurpose solution-induced corneal staining.
abstract: OBJECTIVE
  Use of polyhexanide based multipurpose solutions (MPSs) for contact lens disinfection has been linked to low-grade corneal staining. In vitro data suggest that carboxymethylcellulose (CMC) may neutralize polyhexanides. The purpose of this investigation was to determine whether a pre-application drop of CMC reduces polyhexanide staining in vivo.
  
  
  METHODS
  Thirty adapted soft contact lens (SCL) wearers participated in this investigator-masked, randomized, two-way cross-over study. Subjects wore a new Group II lens (alphafilcon A, 66% water) daily for 4 weeks and disinfected lenses using a MPS containing 0.0001% polyaminopropyl biguanide. A lens lubricant containing either CMC or povidone as the primary viscolyzer was applied to the lens each day before lens wear. Biomicroscopic signs and symptomatology were assessed. The difference in scores, 0 to 4 weeks and the difference between lubricants were analyzed.
  
  
  RESULTS
  The cumulative fluorescein staining scores for combined eyes demonstrated a significant increase over time (e.g., cumulative staining score; p=0.004 and p<0.001 for CMC and povidone, respectively, matched pairs t-test, two-tailed), suggesting that for both lubricants the staining worsened with wear. This effect was expected and likely driven by the MPS. However, the mean cumulative staining scores for CMC and povidone were 2.8 and 2.6 out of 20 possible at baseline, increasing to 4.9 and 7.1 at 4 weeks, respectively. The increases were significantly different (p=0.003, matched pairs t-test, two-tailed) suggesting a greater increase in corneal staining for the povidone lubricant. The symptom scores were not significantly different, 0 to 4 weeks by regimen or between preinstillation drops.
  
  
  CONCLUSIONS
  These results suggest that a CMC-containing preapplication drop can reduce corneal staining resulting from disinfection with a polyhexanide MPS. This result is consistent with a proposed mechanism for CMC to neutralize cationic disinfectants and may offer clinicians another means to reduce this type of corneal staining.
authors.affiliation: Southern California College of Optometry, Fullerton, Fullerton, California 92831, USA. jpaugh@scco.edu
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Paugh
authors.forename: Harue J
authors.initials: HJ
authors.lastname: Marsden
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Edrington
authors.forename: Paul N
authors.initials: PN
authors.lastname: Deland
authors.forename: Peter A
authors.initials: PA
authors.lastname: Simmons
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Vehige
mesh_terms: D000328:Adult; D001645:Biguanides / Q000009:adverse effects*; D002266:Carboxymethylcellulose Sodium / Q000008:administration & dosage*; D018639:Contact Lens Solutions / Q000009:adverse effects*; D003262:Contact Lenses, Extended-Wear; D003315:Cornea / Q000187:drug effects* / Q000473:pathology; D003316:Corneal Diseases / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D018592:Cross-Over Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009883:Ophthalmic Solutions; D012030:Refractive Errors / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D001645:Biguanides; D018639:Contact Lens Solutions; D009883:Ophthalmic Solutions; C031233:polihexanide; D002266:Carboxymethylcellulose Sodium