title: Characteristics of and risk factors for contact lens-related microbial keratitis in a tertiary referral hospital.
abstract: OBJECTIVE
  A retrospective case-control study was conducted at a tertiary referral hospital to determine the characteristics of and risk factors for contact lens (CL) related presumed microbial keratitis.
  
  
  METHODS
  Two hundred and ninety-one cases of presumed microbial keratitis were retrospectively identified over a 2-year period. Records were reviewed for a history of CL wear and, where identified, CL, demographic, and clinical data were collected. Lens wearing controls (n=186) were identified by a community telephone survey. Multiple logistic regression estimated risk factors for infection and vision loss.
  
  
  RESULTS
  Ninety-nine (34%) new cases of presumed microbial keratitis were associated with CL wear. Overnight soft CL use was associated with an increased risk of infection compared to daily disposable CL wear (odds ratio (OR): 8.03, 95% confidence interval (CI): 1.82-35.46). Compared with older CL wearers, 15-24 year olds had a 3.5 times greater risk of infection (OR, 95% CI: 1.7-7.4). Of the 84 cases with available data, 24 (29%) lost two or more lines of best-corrected visual acuity. Delaying treatment by 49-72 h had a 4.5 times (OR, 95% CI: 1.4-14.9) greater risk of visual loss compared to seeking treatment early. Of the 99 cases of infection, 88 were scraped and 78% (69/88) of these returned a positive culture. Gram-positive bacteria were the predominant causative organisms.
  
  
  CONCLUSIONS
  Overnight use of CL and youth carry a greater risk of infection. Practitioners should reinforce the importance of proper CL care at all times, and early presentation following the onset of symptoms.
authors: School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.
authors: K
authors: K
authors: Edwards
authors: L
authors: L
authors: Keay
authors: T
authors: T
authors: Naduvilath
authors: G
authors: G
authors: Snibson
authors: H
authors: H
authors: Taylor
authors: F
authors: F
authors: Stapleton
mesh_terms: D000293:Adolescent; D000328:Adult; D001766:Blindness / Q000382:microbiology; D003261:Contact Lenses / Q000009:adverse effects*; D004812:Epidemiologic Methods; D015817:Eye Infections / Q000209:etiology*; D005260:Female; D006801:Humans; D007634:Keratitis / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D012621:Seasons; D014195:Travel; D055815:Young Adult