Treatment of Early Acanthamoeba Keratitis With Alcohol-Assisted Epithelial Debridement

Abstract

To study the safety and efficacy of treating early-stage Acanthamoeba keratitis (AK) with 20% alcohol-assisted epithelial debridement. Four consecutive patients (2 wearing orthokeratology lenses and 2 wearing soft contact lenses) presented with pseudodendrites, radial keratoneuritis, and epithelial irregularities. Using a technique similar to laser-assisted subepithelial keratomileusis, we performed alcohol-assisted full-thickness debridement of the corneal epithelium and sent portions for smears, histopathologic and ultrastructural examinations, and culture for evidence of Acanthamoeba. Patients were then started on topical propamidine isethionate and 0.02% polyhexamethylene biguanide. Immediately after debridement, minimal underlying anterior stromal infiltrate or haze was seen. Dosages of antiamoebic agents were tapered as corneal defects reepithelialized (in 1-3 weeks) with no evidence of post-debridement corneal infection. At the final follow-up, 1 cornea was transparent and the other 3 corneas had very faint subepithelial haze. Cultures of all epithelial debridement specimens yielded Acanthamoeba trophozoites and cysts, and histopathologic and electron microscopic examinations revealed Acanthamoeba organisms within corneal epithelial layers. Alcohol-assisted epithelial debridement facilitates detachment of the full-thickness corneal epithelial layer in a controlled manner and seems to be effective in the treatment of early-stage AK. Unlike the fragile fragmented specimens obtained by mechanical scraping without alcohol soaking, epithelial sheets detached easily and the architectures were well preserved, permitting histopathologic and ultrastructural examinations. Most importantly, 20% alcohol-assisted epithelial debridement did not prevent culturing of Acanthamoeba from the removed epithelial specimens.