title: Risk factors for moderate and severe microbial keratitis in daily wear contact lens users.
abstract: OBJECTIVE
  To establish risk factors for moderate and severe microbial keratitis among daily contact lens (CL) wearers in Australia.
  
  
  METHODS
  A prospective, 12-month, population-based, case-control study.
  
  
  METHODS
  New cases of moderate and severe microbial keratitis in daily wear CL users presenting in Australia over a 12-month period were identified through surveillance of all ophthalmic practitioners. Case detection was augmented by record audits at major ophthalmic centers. Controls were users of daily wear CLs in the community identified using a national telephone survey.
  
  
  METHODS
  Cases and controls were interviewed by telephone to determine subject demographics and CL wear history. Multiple binary logistic regression was used to determine independent risk factors and univariate population attributable risk percentage (PAR%) was estimated for each risk factor.
  
  
  METHODS
  Independent risk factors, relative risk (with 95% confidence intervals [CIs]), and PAR%.
  
  
  RESULTS
  There were 90 eligible moderate and severe cases related to daily wear of CLs reported during the study period. We identified 1090 community controls using daily wear CLs. Independent risk factors for moderate and severe keratitis while adjusting for age, gender, and lens material type included poor storage case hygiene 6.4× (95% CI, 1.9-21.8; PAR, 49%), infrequent storage case replacement 5.4× (95% CI, 1.5-18.9; PAR, 27%), solution type 7.2× (95% CI, 2.3-22.5; PAR, 35%), occasional overnight lens use (<1 night per week) 6.5× (95% CI, 1.3-31.7; PAR, 23%), high socioeconomic status 4.1× (95% CI, 1.2-14.4; PAR, 31%), and smoking 3.7× (95% CI, 1.1-12.8; PAR, 31%).
  
  
  CONCLUSIONS
  Moderate and severe microbial keratitis associated with daily use of CLs was independently associated with factors likely to cause contamination of CL storage cases (frequency of storage case replacement, hygiene, and solution type). Other factors included occasional overnight use of CLs, smoking, and socioeconomic class. Disease load may be considerably reduced by attention to modifiable risk factors related to CL storage case practice.
authors.affiliation: Brien Holden Vision Institute, Sydney, Australia. F.Stapleton@unsw.edu.au
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
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: John K G
authors.initials: JK
authors.lastname: Dart
authors.forename: Garry
authors.initials: G
authors.lastname: Brian
authors.forename: Brien
authors.initials: B
authors.lastname: Holden
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000302:isolation & purification*; D016022:Case-Control Studies; D018639:Contact Lens Solutions / Q000627:therapeutic use; D003261:Contact Lenses / Q000009:adverse effects* / Q000706:statistics & numerical data*; D003320:Corneal Ulcer / Q000453:epidemiology* / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D006920:Hygiene; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D018639:Contact Lens Solutions