title: Clinical characteristics of Acanthamoeba keratitis infections in 28 states, 2008 to 2011.
abstract: OBJECTIVE
  The aim was to describe a geographically and clinically diverse sample of cases of Acanthamoeba keratitis (AK) and establish the risk factors for poor outcomes among patients with this disease.
  
  
  METHODS
  We conducted a retrospective, population-based case series of 116 patients with AK identified through a national surveillance network. Data were collected via a medical record review by diagnosing ophthalmologists and by phone interviews with patients. Exact logistic regression modeling was used to determine risk factors for poor visual outcomes.
  
  
  RESULTS
  Among patients with data available on contact lens use, it was found that 93.3% wore contact lenses. The median time from symptom onset to care seeking was 2 days, whereas the median time from symptom onset to diagnosis was 27 days. Keratoplasty was performed in 27 of 81 patients with available outcome data and was more likely in patients >40 years old [odds ratio (OR) 5.25, 95% confidence interval (CI) 1.49-21.92]. When adjusted for age, the risk factors for keratoplasty included the presence of a ring infiltrate (OR 40.00, 95% CI 3.58-447.0) or any sign of stromal invasion (OR 10.48, 95% CI 2.56-55.09). One-third of patients with available data on best-corrected visual acuity had a best-corrected visual acuity <20/200, with the presence of a ring infiltrate as the only significant predictor of this outcome when adjusted for age (aOR 3.45, 95% CI 1.01-12.31).
  
  
  CONCLUSIONS
  AK remains challenging to diagnose. Consequently, patients with advanced disease are more likely to have poor outcomes, particularly if they are older. The increasing awareness of AK among general eye care providers may shorten referral times and potentially improve outcomes.
authors: *Division of Foodborne, Waterborne and Environmental Disease, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA; †Casey Eye Institute, Oregon Health and Science University, Portland, OR; ‡Department of Ophthalmology, New York Eye and Ear Infirmary, New York, NY; §Department of Ophthalmology, Case Western Reserve University, Cleveland, OH; ¶Acute and Communicable Disease Prevention Section, Oregon Public Health Division, Portland, OR; ‖Department of Ophthalmology, North Shore University Hospital, Great Neck, NY; and **Bureau of Epidemiology, Florida Department of Health, Tallahassee, FL.
authors: Jonathan
authors: J
authors: Ross
authors: Sharon L
authors: SL
authors: Roy
authors: William D
authors: WD
authors: Mathers
authors: David C
authors: DC
authors: Ritterband
authors: Jonathan S
authors: JS
authors: Yoder
authors: Tracy
authors: T
authors: Ayers
authors: Rupa D
authors: RD
authors: Shah
authors: Monika E
authors: ME
authors: Samper
authors: Carolyn Y
authors: CY
authors: Shih
authors: Ann
authors: A
authors: Schmitz
authors: Allison C
authors: AC
authors: Brown
mesh_terms: D015823:Acanthamoeba Keratitis / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology* / Q000469:parasitology; D000328:Adult; D000563:Amebicides / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D000563:Amebicides