title: A population survey of the penetrance of contact lens wear in Australia: rationale, methodology and results.
abstract: OBJECTIVE
  A population based, cross-sectional telephone survey was conducted to estimate the total penetrance of contact lens wear in Australia.
  
  
  METHODS
  A total of 42,749 households around Australia were randomly selected from the national electronic telephone directory based on postcode distribution. Before contact was attempted, letters of introduction were sent. The number of individuals and contact lens wearers in each household was ascertained and lens wearers were interviewed to determine details of lens type and mode of wear using a structured questionnaire.
  
  
  RESULTS
  Of households contacted, 59.2% (19,171/32,405) agreed to participate. Response rates were only marginally higher amongst households that first received a letter of introduction. In these households, 35,914 individuals were identified, of which, 1,798 were contact lens wearers. The penetrance of contact lens wear during the study period was 5.01% (95% CI: 4.78-5.24). Soft hydrogel lenses had the largest penetrance in the community, (66.7% of all wearers), however, their market share decreased significantly over the study period with increased uptake of newly introduced lens types.
  
  
  CONCLUSIONS
  The penetrance of contact lens wear concurs with market estimates and equates to approximately 680,000 contact lens wearers aged between 15 and 64 years in Australia. The low response rate obtained in this study highlights the difficulty in contemporary use of telephone survey methodology.
authors.affiliation: Institute for Eye Research, Sydney, Australia. katie.edwards@qut.edu.au
authors.forename: Katie
authors.initials: K
authors.lastname: Edwards
authors.forename: Lisa
authors.initials: L
authors.lastname: Keay
authors.forename: Thomas
authors.initials: T
authors.lastname: Naduvilath
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D003261:Contact Lenses / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000453:epidemiology / Q000628:therapy; D011795:Surveys and Questionnaires; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D055815:Young Adult