41–44 AK has also been reported after using contaminated contact lens cleansing solutions, following corneal trauma, and, rarely, after radial keratotomy.41–44 Mitomycin C chemical structure The incidence rate of AK has been increasing worldwide and is now reported to be 10,000 cases per year or 1 to 2 cases per 1 million soft contact lens wearers in the United States, or approximately 10,000 cases per year among contact lens users worldwide.42,43 A significant outbreak of AK in US contact lens wearers was first confirmed by the CDC in January 2007 after an increasing number of cases
were reported in Chicago, Illinois, in late 2006.42,43 In March 2007, the CDC completed a retrospective survey analysis of AK cases from 22 national ophthalmology centers and documented an increase in US culture-confirmed cases of AK beginning in 2004, a widespread geographic distribution.42,43 By June 2007, the CDC had received reports from state public health departments and ophthalmologists from 37 US states and Puerto Rico identifying 221 patients with AK, 158 of whom had culture-positive AK.42,43 PI3K inhibitor A risk factor analysis of culture-confirmed cases demonstrated a significant association between AK in soft contact lens wearers and the use of a
specific brand of multi-purpose contact lens cleanser solution, Complete® MoisturePlus™ (Advanced Medical Optics, Santa Ana, CA, USA).42–44 This product was recalled immediately and removed
from the US market. Contact lens wearers were advised to: (1) stop using the product immediately and discard remaining solutions; (2) choose an alternative contact lens solution; (3) discard current contact lens storage containers; and (4) see an eye-care provider if experiencing any signs of eye infection, including eye pain, redness, blurred vision, photophobia, excessive tearing, or foreign body sensation.43,44 An analysis of significant risk factors for AK is presented in Table 5. The presenting clinical manifestations of AK include a prodrome of days of unilateral ocular redness, foreign body sensation, and excessive tearing, MRIP followed by intense ocular pain. Confocal microscopy will confirm dendriform epitheliopathy; and corneal smears or fixed, stained corneal scrapings often demonstrate Acanthamoeba spp cysts and/or trophozoites.41–43 PCR assays for the detection of Acanthamoeba nucleic acids will also confirm diagnosis.42,43 Early treatment with topical 0.02% chlorhexadine, 0.02% polyhexamethylene biguanide, or 1% imidazole, often combined with an oral azole (itraconazole, ketoconazole, or voriconazole), is successful in over 75% of cases; with corneal transplant or enucleation reserved for treatment failures.