title: Microbial keratitis predisposing factors and morbidity.
abstract: OBJECTIVE
  To examine predisposing factors, treatment costs, and visual outcome of microbial keratitis in an ophthalmic casualty and inpatient population.
  
  
  METHODS
  Retrospective medical records review.
  
  
  METHODS
  Fifteen- to 64-year-olds with microbial keratitis treated at the Royal Victorian Eye and Ear Hospital between May 2001 and April 2003 (n = 291).
  
  
  METHODS
  Risk factors were identified from patient files. Demographic, clinical, and microbiological data; severity; outpatient visits; hospital bed days; and vision loss were examined.
  
  
  METHODS
  Cost to treat (Australian dollars), vision loss, and factors influencing these outcomes.
  
  
  RESULTS
  Ocular trauma (106/291 [36.4%]) and contact lens (CL) wear (98/291 [33.7%]) were the most commonly identified predisposing factors; 18 (6.1%) had multiple predisposing factors; 17 (5.8%), ocular surface disease; 20 (6.9%), herpetic eye disease; 4 (1.4%), systemic associations; 5 (1.7%), other; and 23 (7.9%), unknown cause. Of trauma cases, 90.6% involved males, compared with 44% to 57% for other groups (P<0.001). Contact lens wearers were younger than the other groups--mean age 30 years, compared with 40 to 47 years (P<0.01). Gram-negative organisms were isolated more frequently in CL wearers than trauma cases (18.7% vs. 6.5%, P = 0.01). The number of outpatient visits was 4+/-1 (median +/- interquartile range), and 19.6% (57/291) were hospitalized for 5+/-2 days. Hospital resource use and vision loss were similar for predisposing factors but differed by causative microorganism. Eighty-eight percent of cases were scraped: acanthamoeba keratitis was the most expensive to treat, followed by fungal and herpetic keratitis and, lastly, culture-proven bacterial keratitis or culture-negative cases (P<0.0001). After treatment, 21.7% exhibited >2 lines of vision loss, and 1.6% of cases had > or =10 lines of vision loss. Vision loss was associated with clinical severity (P = 0.005).
  
  
  CONCLUSIONS
  Ocular trauma and CL wear are the major predisposing factors for microbial keratitis in this age range. These cases require significant hospital resources during treatment, and the keratitis may result in loss of vision.
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Keay
authors.forename: Katie
authors.initials: K
authors.lastname: Edwards
authors.forename: Thomas
authors.initials: T
authors.lastname: Naduvilath
authors.forename: Hugh R
authors.initials: HR
authors.lastname: Taylor
authors.forename: Grant R
authors.initials: GR
authors.lastname: Snibson
authors.forename: Kevin
authors.initials: K
authors.lastname: Forde
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
mesh_terms: D015823:Acanthamoeba Keratitis / Q000191:economics / Q000453:epidemiology* / Q000469:parasitology; D000293:Adolescent; D000328:Adult; D003261:Contact Lenses / Q000706:statistics & numerical data; D003320:Corneal Ulcer / Q000191:economics / Q000453:epidemiology* / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000191:economics / Q000453:epidemiology* / Q000382:microbiology; D005131:Eye Injuries / Q000453:epidemiology; D005260:Female; D017048:Health Care Costs; D017721:Hospital Costs; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D012189:Retrospective Studies; D012307:Risk Factors