title: The impact of lens care solutions on corneal epithelial changes during daily silicone hydrogel contact lens wear as measured by in vivo confocal microscopy.
abstract: OBJECTIVE
  To assess corneal epithelial microstructure via confocal microscopy and determine if cellular changes are associated with lens care solutions during daily wear of silicone hydrogel contact lenses.
  
  
  METHODS
  Corneal in vivo confocal microscopy with the Nidek ConfoScan4 was performed at baseline and after 5 months of lotrafilcon A daily contact lens wear. Enrolled participants were randomized to use either a polyhexamethylene biguanide (PHMB) preserved multipurpose care solution (MPS) or a peroxide based solution system. Lens and storage case bioburden were assessed with aerobic culture methods. Univariate and multivariable analyses were done to evaluate the association between solution use, or solution-related clinical covariates, and morphologic differences (hyper-reflectivity) in the superficial epithelial cells and epithelial basal cell density.
  
  
  RESULTS
  Data on 139 participants were available for analysis of superficial epithelial cells while data on 92 participants were available for epithelial basal cell density. Five months after randomization to the solution groups, 33% of participants had visible hyper-reflective cells. More participants using MPS had ≥1 hyper-reflective cells compared to peroxide users at 5 months (44% vs. 22%; p=0.006). Similarly at 5 months, more participants with solution-induced corneal staining (SICS) had ≥1 hyper-reflective cells compared to non-SICS participants (57% vs. 29%; p=0.010). The adjusted odds ratios (ORs) for risk of presenting with hyper-reflective cells in MPS users or SICS participants was 2.7 (95% CI; 1.27-5.65) and 3.4 (95% CI; 1.29-8.97), respectively. Basal cell density decreased by over 350 cells/mm2over time (about 6%) in participants who had substantial bioburden on their lenses or in their storage case.
  
  
  CONCLUSIONS
  The confocal microscope can detect epithelial cellular changes in vivo during contact lens wear. Hyper-reflective superficial epithelial cells are associated with a PHMB preserved solution and decreases in basal epithelial cell density may be associated with bacterial bioburden.
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Christine
authors.initials: C
authors.lastname: Marchetti
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Jessica
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Epidemiology & Biostatistics, Case Western Reserve University, Cleveland, OH, United States.
authors.forename: Sara
authors.initials: S
authors.lastname: Debanne
authors.affiliation: Department of Epidemiology & Biostatistics, Case Western Reserve University, Cleveland, OH, United States.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Alcon Research, Fort Worth, TX, United States.
authors.forename: Jami
authors.initials: J
authors.lastname: Kern
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Harrod
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States.
authors.forename: Beth Ann
authors.initials: BA
authors.lastname: Benetz
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States; Department of Ophthalmology, University of California, Irvine, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Pearlman
authors.affiliation: Department of Ophthalmology & Visual Sciences and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH, United States. Electronic address: loretta.szczotka@uhhospitals.org.
authors.forename: Loretta
authors.initials: L
authors.lastname: Szczotka-Flynn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002452:Cell Count; D018639:Contact Lens Solutions / Q000008:administration & dosage* / Q000737:chemistry; D003263:Contact Lenses, Hydrophilic; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D019573:Epithelium, Corneal / Q000166:cytology* / Q000000981:diagnostic imaging / Q000187:drug effects*; D006801:Humans; D000069416:Intravital Microscopy / Q000379:methods; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D020034:Silicone Gels / Q000737:chemistry*; D055815:Young Adult
chemical_list: D018639:Contact Lens Solutions; D020034:Silicone Gels
keywords: Confocal microscopy; Hyper-reflective corneal epithelial cells; Silicone hydrogel contact lens