title: Epidemiology of ulcerative keratitis in Northern California.
abstract: OBJECTIVE
  To determine the incidence and associated risk factors for ulcerative keratitis in northern California.
  
  
  METHODS
  In this large-population, retrospective, cohort study, all medical records with diagnosis coding for corneal ulcers during a consecutive 12-month period were reviewed. Incidence rates were calculated using a dynamic population model. Multivariate relative risk regression was conducted to evaluate potential risk factors for ulcerative keratitis.
  
  
  RESULTS
  Within the target population of 1 093 210 patients, 302 developed ulcerative keratitis. The incidence of ulcerative keratitis was 27.6 per 100 000 person-years (95% confidence interval, 24.6-30.9). The incidence of corneal ulceration in contact lens wearers was 130.4 per 100 000 person-years (95% confidence interval, 111.3-151.7), with an adjusted relative risk of 9.31 (7.42-11.7; P < .001) compared with non-contact lens wearers, who had an incidence of ulcerative keratitis of 14.0 per 100 000 person-years (11.7-16.6). Seven of 2944 people known to be infected with human immunodeficiency virus developed ulcerative keratitis, with 5 being contact lens wearers. The incidence of ulcerative keratitis in human immunodeficiency virus-positive patients was 238.1 per 100 000 person-years (95% confidence interval, 95.7-490.5), with an odds ratio of 9.31 (7.42-11.7; P < .001) compared with human immunodeficiency virus-negative patients, who had an incidence of ulcerative keratitis of 27.1 per 100 000 person-years (24.1-30.3).
  
  
  CONCLUSIONS
  The incidence of ulcerative keratitis in this population is higher than previously reported. This may be owing to the increasing prevalence of contact lens wear.
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, USA.
authors.forename: Bennie H
authors.initials: BH
authors.lastname: Jeng
authors.forename: David C
authors.initials: DC
authors.lastname: Gritz
authors.forename: Abha B
authors.initials: AB
authors.lastname: Kumar
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Holsclaw
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Scott D
authors.initials: SD
authors.lastname: Smith
authors.forename: John P
authors.initials: JP
authors.lastname: Whitcher
authors.forename: Todd P
authors.initials: TP
authors.lastname: Margolis
authors.forename: Ira G
authors.initials: IG
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003261:Contact Lenses / Q000706:statistics & numerical data; D003320:Corneal Ulcer / Q000453:epidemiology* / Q000382:microbiology; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D015818:Eye Infections, Bacterial / Q000453:epidemiology / Q000382:microbiology; D015821:Eye Infections, Fungal / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006679:HIV Seropositivity; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D055815:Young Adult