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2018 Agenda and Abstracts | < Previous Next >

2018 OMIG Abstract

Factors Associated With Acanthamoeba Keratitis Clearance Time

Todd Driver, MD1,2, Revathi Rajaraman, MD3, Arun Panigrahi, MS4, Lalitha Prajna, MD, DNB4, N Venkatesh Prajna, DO, DNB, FRCO4, Vicky Cevallos, MT 1,2, Gerami D Seitzman, MD1,2, Thomas M Lietman, MD1,2, Jeremy D Keenan, MD, MPH1,2
1F.I. Proctor Foundation, San Francisco, CA, USA; 2Department of Ophthalmology, San Francisco, CA, USA; 3Aravind Eye Care System, Coimbatore, India; 4Aravind Eye Care System, Madurai, India


Purpose: To determine the duration of treatment necessary to clear acanthamoeba from the corneal surface.

Methods: Patients from the Aravind Eye Hospital-Madurai, Aravind Eye Hospital-Coimbatore, and Proctor Foundation with a smear or culture positive for acanthamoeba were enrolled in a prospective cohort study from 2011-2017. The majority of patients were treated with PHMB monotherapy. Repeat corneal scraping was done every 2 weeks until two consecutive negative cultures were achieved. Survival analysis methods were used to describe the clearance of acanthamoeba from the corneal surface.

Results: 52 patients with culture-positive acanthamoeba keratitis were enrolled, with 32 from Madurai, 15 from Coimbatore, and 5 from Proctor. Of these, 40 had a follow-up culture that was negative. The median time until a negative culture was 28 days (95%CI 16-58). Median clearance time was significantly delayed in eyes with larger infiltrates at baseline (33 days vs. 15 days, p=0.04, with large infiltrate defined as a geometric mean > 5.8mm) and ring infiltrates at baseline (33 days vs. 16 days, p=0.046). Clearance time was not associated with baseline presenting visual acuity, corneal hypoesthesia, or topical steroid use, nor with enrollment site.

Conclusion: Acanthamoeba corneal infections were long-lived in this population with a ring- or larger baseline infiltrate being associated with longer clearance time. Microbial clearance had not occurred by 1 month for half the eyes in this study, and had not occurred by 2 months for a quarter. Moreover, because corneal scrapings do not capture viable organisms beneath the ocular surface, courses of therapy of even longer durations are likely required.


Support: Research to Prevent Blindness, That Man May See.


2018 Agenda and Abstracts | < Previous Next >