title: Risk factors for contact lens-related microbial keratitis in Singapore.
abstract: OBJECTIVE
  To investigate independent risk factors for contact lens-related microbial keratitis in Singapore and estimate their impact on disease load.
  
  
  METHODS
  Cases were contact lens wearers presenting to Singapore National Eye Centre with microbial keratitis between 2008 and 2010. Community contact lens wearers were recruited as controls. All wearers completed a previously validated questionnaire describing contact lens wear history, hygiene and compliance habits, and demographics. Risk factors significant in univariate analysis (P<0.2) were evaluated in a multivariate model.
  
  
  RESULTS
  In all, 58 cases of microbial keratitis and 152 contemporaneous controls were identified. When controlling for other variables, Chinese had a 7 × lower risk compared with other races (95% CI: 2.3-21.3, P=0.001). Those aged between 25 and 44 years were at 3 × increased risk compared with younger wearers (95% CI: 1.1-9.6, P=0.04). Occasional overnight contact lens wear (less often than one night per week) was associated with a 4 × higher risk (95% CI: 1.2-15.4, P=0.03) compared with daily use. Not washing hands before handling was associated with a 13 × increased risk (95% CI: 1.9-84.8, P=0.008). Use of multipurpose solution A carried a 16 × higher risk compared with hydrogen peroxide (95% CI: 1.5-174.0, P=0.02). The combined PAR% for modifiable risk factors (occasional overnight wear, not washing of hands, and MPS A) was 82%.
  
  
  CONCLUSIONS
  Consistent with previous findings, independent risk factors for contact lens-related microbial keratitis include poor hand hygiene, occasional overnight wear, and type of lens care solution. Prolonged overnight or extended contact lens use was infrequent in this population.
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.|Royal Melbourne Hospital, Parkville, VIC, Australia.
authors.forename: C H L
authors.initials: CH
authors.lastname: Lim
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.|Moorfields Eye Hospital Trust, London, UK.
authors.forename: N A
authors.initials: NA
authors.lastname: Carnt
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Farook
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.|Department of Ophthalmology, National University Hospital, Singapore, Singapore.
authors.forename: J
authors.initials: J
authors.lastname: Lam
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.|Department of Ophthalmology, National University Hospital, Singapore, Singapore.|Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.|Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: D T
authors.initials: DT
authors.lastname: Tan
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.|Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: J S
authors.initials: JS
authors.lastname: Mehta
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.
authors.forename: F
authors.initials: F
authors.lastname: Stapleton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003261:Contact Lenses / Q000009:adverse effects*; D003320:Corneal Ulcer / Q000453:epidemiology* / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology; D012307:Risk Factors; D016868:Serratia Infections / Q000453:epidemiology / Q000382:microbiology; D012846:Singapore / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D011795:Surveys and Questionnaires; D055815:Young Adult