Prognostic Factors Affecting Visual Outcome in Acanthamoeba Keratitis
Received 11 February 2008; received in revised form 15 March 2008; accepted 25 April 2008. published online 25 June 2008.
Objective
To identify clinical and demographic factors associated with a worse visual outcome in Acanthamoeba keratitis (AK).
Design
Retrospective, case control study.
Participants
A total of 72 eyes of 65 patients with AK who were diagnosed at the University of Illinois Eye and Ear Infirmary between May of 2003 and May of 2007 with treatment complete by October of 2007. The first affected eye was analyzed in bilateral disease.
Methods
Patient demographic, clinical characteristics, treatment methods, and final visual outcome data were collected through medical record reviews for all patients diagnosed with AK. Cases were defined as patients with AK with a visual outcome worse than 20/25 or those requiring penetrating keratoplasty (PKP). Controls were defined as patients with AK with a visual outcome of 20/25 or better. Logistic regression was used to estimate the odds ratio (OR) identifying prognostic factors associated with a worse visual outcome.
Main Outcome Measures
Final visual outcome worse than 20/25.
Results
AK was confirmed through microbiologic evidence in 48 of 65 eyes (73.8%) or with confocal microscopy in 62 of 65 eyes (95.4%). Final visual acuity data were available in 61 of 65 eyes (93.8%); of these 61 eyes, 40 (65.6%) achieved a final visual acuity of 20/25 or better. In multivariable analysis, deep stromal involvement or the presence of a ring infiltrate at presentation was independently associated with worse visual outcomes (OR, 10.27; 95% confidence interval [CI], 2.91–36.17). Symptom duration before diagnosis was statistically predictive of disease stage at presentation (OR, 4.43; 95% CI, 0.99–19.83; multivariable analysis) but not final visual outcome (OR, 2.55; 95% CI, 0.83–7.88; univariate analysis). PKP was performed in 11 of 12 eyes with active disease.
Conclusions
Corneal disease staging at presentation with slit-lamp examination was highly predictive of worse outcomes, allowing the identification of patients who might benefit from more aggressive medical or surgical intervention. Unlike in previous reports, patient-reported duration of symptoms before treatment was not reliable in predicting the final visual result in our series.
Financial Disclosure(s)
The authors have no proprietary or commercial interest in any materials discussed in this article.
Available online: June 24, 2008.
1University of Illinois at Chicago, Department of Ophthalmology, Chicago, Illinois
2University of Illinois at Chicago, Division of Epidemiology and Biostatistics, School of Public Health, Chicago, Illinois
3The Ohio State University, Department of Evolution, Ecology, and Organismal Biology, Columbus, Ohio
4The Ohio State University, Department of Molecular Genetics, Columbus, Ohio
Correspondence: Elmer Y. Tu, MD, University of Illinois at Chicago, Department of Ophthalmology, 1855 West Taylor Street (M/C 648), Room 3.164, Chicago, IL 60612
Manuscript no. 2008-200.
Financial Disclosure(s): No authors have a financial interest in the study.
Supported by grants from National Institutes of Health (EY15689 and EY09073), Bethesda, Maryland; Prevent Blindness America, Chicago, Illinois; Midwest Eye-Banks, Ann Arbor, Michigan; University of Illinois at Chicago Campus Research Board, Chicago, Illinois; AOF AAO William C. Ezell Fellowship, Rockville, Maryland; and Karl Cless Foundation, Northbrook, Illinois.
ABSTRACT