title: A 'cost-per-wear' model based on contact lens replacement frequency.
abstract: OBJECTIVE
  The aim was to construct and advise on the use of a cost-per-wear model based on contact lens replacement frequency, to form an equitable basis for cost comparison.
  
  
  METHODS
  The annual cost of professional fees, contact lenses and solutions when wearing daily, two-weekly and monthly replacement contact lenses is determined in the context of the Australian market for spherical, toric and multifocal prescription types. This annual cost is divided by the number of times lenses are worn per year, resulting in a 'cost-per-wear'. The model is presented graphically as the cost-per-wear versus the number of times lenses are worn each week for daily replacement and reusable (two-weekly and monthly replacement) lenses.
  
  
  RESULTS
  The cost-per-wear for two-weekly and monthly replacement spherical lenses is almost identical but decreases with increasing frequency of wear. The cost-per-wear of daily replacement spherical lenses is lower than for reusable spherical lenses, when worn from one to four days per week but higher when worn six or seven days per week. The point at which the cost-per-wear is virtually the same for all three spherical lens replacement frequencies (approximately AUD$3.00) is five days of lens wear per week. A similar but upwardly displaced (higher cost) pattern is observed for toric lenses, with the cross-over point occurring between three and four days of wear per week (AUD$4.80). Multifocal lenses have the highest price, with cross-over points for daily versus two-weekly replacement lenses at between four and five days of wear per week (AUD$5.00) and for daily versus monthly replacement lenses at three days per week (AUD$5.50).
  
  
  CONCLUSIONS
  This cost-per-wear model can be used to assist practitioners and patients in making an informed decision in relation to the cost of contact lens wear as one of many considerations that must be taken into account when deciding on the most suitable lens replacement modality.
authors.affiliation: Institute of Health and Biomedical Innovation and School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia. n.efron@qut.edu.au
authors.forename: Nathan
authors.initials: N
authors.lastname: Efron
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Efron
authors.forename: Philip B
authors.initials: PB
authors.lastname: Morgan
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Morgan
mesh_terms: D001315:Australia; D018639:Contact Lens Solutions / Q000191:economics; D003261:Contact Lenses / Q000145:classification / Q000191:economics*; D004209:Disposable Equipment / Q000191:economics; D004867:Equipment Design; D005251:Fees, Medical; D017048:Health Care Costs; D006801:Humans; D018803:Models, Economic; D009907:Optometry / Q000191:economics; D013997:Time Factors
chemical_list: D018639:Contact Lens Solutions