Clinical outcomes and prognostic factors associated with acanthamoeba keratitis

Cornea. 2011 Apr;30(4):435-41. doi: 10.1097/ICO.0b013e3181ec905f.


Purpose: To describe the clinical characteristics, time of presentation, risk factors, treatment, outcomes, and prognostic factors on a recent series of Acanthamoeba keratitis (AK) treated at our institution.

Methods: Retrospective case series of 59 patients diagnosed with AK from January 1, 2004 to December 31, 2008. Of these 59 patients, 51 had complete follow-up data and were analyzed using univariate and multivariate logistic regression analyses performed with "failure" defined as requiring a penetrating keratoplasty (PKP) and/or having (1) best-corrected visual acuity (BCVA) < 20/100 or (2) BCVA < 20/25 at the last follow-up. A single multivariate model incorporating age, sex, steroid use before diagnosis, time to diagnosis, initial visual acuity (VA), stromal involvement, and diagnostic method was performed.

Results: Symptom onset was greatest in the summer and lowest in the winter. With failure defined as requiring PKP and/or final BCVA < 20/100, univariate analysis suggests that age > 50 years, female sex, initial VA < 20/50, stromal involvement, and patients with a confirmed tissue diagnosis had a significant risk for failure; however, none of these variables were significant using multivariate analysis. Univariate analysis, with failure defined as requiring PKP and/or final BCVA < 20/25, showed stromal involvement and initial VA < 20/50 were significant for failure-only initial VA < 20/50 was significant using multivariate analysis.

Conclusions: Symptom onset for AK is greatest in the summer. Patients with confirmed tissue diagnosis and female patients may have a higher risk for failure, but a larger prospective population-based study is required to confirm this. Failure is likely associated with patients who present with stromal involvement and patients presenting with an initial BCVA worse than 20/50.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acanthamoeba Keratitis / diagnosis*
  • Acanthamoeba Keratitis / epidemiology*
  • Acanthamoeba Keratitis / therapy
  • Adolescent
  • Adult
  • Aged
  • Antiprotozoal Agents / therapeutic use
  • Child
  • Cornea / parasitology
  • Cornea / pathology
  • Drug Therapy, Combination
  • Female
  • Follow-Up Studies
  • Humans
  • Keratoplasty, Penetrating
  • Male
  • Middle Aged
  • Retrospective Studies
  • Risk Factors
  • Seasons
  • Treatment Outcome
  • Visual Acuity / physiology


  • Antiprotozoal Agents