title: Risk factors for the development of corneal infiltrative events associated with contact lens wear.
abstract: OBJECTIVE
  To identify risk factors for the development of corneal infiltrative events (CIEs) associated with contact lens wear, and to report other relevant clinical characteristics.
  
  
  METHODS
  A series of symptomatic contact lens wearers presenting consecutively to a large hospital clinic over a 1-year period were examined. The clinical severity of any CIE was determined with a scoring system, and general and lens-specific information was captured with a questionnaire. Logistic regression analyses were performed to investigate the association between a range of risk factors and the occurrence of any CIE and the subset of cases categorized as severe keratitis. Three quasi-independent control groups were used for this analysis: hospital, lens-matched, and population. The relationship between clinical severity and the delay in attending the hospital was investigated. The prevalence of symptoms and initial actions taken by patients are reported.
  
  
  RESULTS
  Factors identified as being associated with an increased risk of development of a CIE include: wearing modality/lens type (greatest risk for extended-wear hydrogel lenses of 7.1 vs. daily wear hydrogel lenses), male gender (relative risk 1.4), smoking (1.4), the absence of relevant ocular (1.8) and general health (2.4) problems, and the late winter months (greatest risk in March of 3.6 vs. July). The overall predictive value of these risk factors for a given individual was low. Shorter time delays in hospital attendance were associated with increasing severity of keratitis. Eye soreness was the most common initial symptom (prevalence 69%), and the most frequent initial course of action taken by the patient was lens removal (prevalence 50%).
  
  
  CONCLUSIONS
  Risk factors for the development of contact lens keratitis were identified that, although being of limited predictive value for individual patients, highlight general associations that may assist in the management of contact lens wearers. Such risk factors may also assist in the development of a more complete understanding of the etiology of contact-lens-associated CEIs.
authors.affiliation: Eurolens Research, The University of Manchester, Manchester M60 1QD, U.K. philip.morgan@manchester.ac.uk
authors.forename: Philip B
authors.initials: PB
authors.lastname: Morgan
authors.forename: Nathan
authors.initials: N
authors.lastname: Efron
authors.forename: Noel A
authors.initials: NA
authors.lastname: Brennan
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Hill
authors.forename: Mathew K
authors.initials: MK
authors.lastname: Raynor
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Tullo
mesh_terms: D000293:Adolescent; D000328:Adult; D003261:Contact Lenses / Q000009:adverse effects* / Q000145:classification; D003320:Corneal Ulcer / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D011795:Surveys and Questionnaires