2007 OMIG, Abstract 16

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The Continuing Rise of Acanthamoeba Keratitis
Hall F. Chew, MD, Kristin M. Hammersmith, MD, Christopher J. Rapuano, MD, Brandon D. Ayres, MD, Peter R. Laibson, MD, Ralph C. Eagle Jr, MD, and Elisabeth J. Cohen, MD
Cornea Service, Wills Eye Institute, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA.

Purpose: To update the continued increase of Acanthamoeba keratitis (AK) recently diagnosed at Wills Eye Hospital from 2006 to 2007. To verify the risk factors, clinical characteristics, treatments and outcomes of patients with AK.
Methods: Retrospective consecutive case series of 21 eyes with AK.
Results: Twenty-one patients were diagnosed with AK: ten patients in all of 2006 and 11 patients from Jan. 1, 2007 to September 7, 2007. One patient did not wear contact lenses, while 20 patients wore frequent replacement contact lenses. All 20 frequent replacement soft contact lens wearers used one-step multipurpose cleaning solutions (MPS). Eleven (55%) used Complete ^® MoisturePlus (AMO, Santa Ana, CA); 3 used Renu ^® (B&L, Rochester, NY); and 2 (10%) used Opti-Free ^® (Alcon, Fort Worth, TX). Four (20%) used unknown MPS. From Jan. 1 to May 31, 2007, there were 3 cases: 2 used Complete ^® MoisturePlus only and 1 used both Complete ^® MoisturePlus and Renu. From June 1 to Sept. 7, 2007, there were 8 cases: 5 used Complete ^® MoisturePlus, 1 used Opti-Free ^® , 1 used an unknown MPS, and 1 was a non-contact lens wearer. Ten patients (50%) swam in their lenses. Six patients (30%) wore their lenses overnight. Four patients (19%) were exposed to well water. Mean time to diagnosis was 28 days (range: 4-90; SD=23.4). Herpes simplex keratitis was misdiagnosed in 13 cases (62%). Bacterial keratitis was misdiagnosed in 10 cases (48%). Topical steroids were used in 14 cases (67%) prior to diagnosis of AK. Narcotic medication was required by 19 of the 21 patients (90%). Cultures were positive for coincidental bacterial growth in 5 patients (24%).  Ten cases (48%) were diagnosed by histopathology, 9 cases (43%) by clinical examination and response to treatment, and two (9%) by corneal biopsy.
Conclusions: There is a continued increase in the incidence of AK at our institution (Ref: Thebpatiphat N. et al. Acanthamoeba Keratitis a Parasite on the Rise. Cornea 2007;26;701-706). The risk factors for AK are multifactorial. AK remains a diagnostic challenge. Despite the voluntary recall of Complete ^® MoisturePlus, AK with this and other MPS still occurs.

Disclosure code: N

Dr. Chew received an E.A. Baker Fellowship Fund grant from the Canadian National Institute for the Blind.

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