Diagnosis and successful medical treatment of Acanthamoeba keratitis

To identify the methods that result in timely diagnosis and effective treatment of Acanthamoeba keratitis.

We retrospectively reviewed the medical records of 12 consecutive patients whom we treated for culture-proved Acanthamoeba keratitis in 14 eyes.

Contact lenses were worn in 13 of 14 affected eyes and substandard methods were often used to care for them. The diagnosis was established in all patients by laboratory analysis of corneal scrapings; corneal biopsies were not required. Acanthamoeba organisms were identified on smears from 12 of 14 eyes with use of standard, nonfluorescent stains and recovered in culture from all patients by inoculating scrapings on nonnutrient agar overlaid with Escherichia coli. Eleven of 14 eyes were medically cured with a combination of antiamebic drugs, most commonly propamidine isethionate, neomycin sulfate, and clotrimazole. Topical corticosteroids were used in only one patient. Two of the three eyes that required therapeutic keratoplasty were not treated before surgery according to our usual protocol; the third required keratoplasty for treatment of a severe bacterial superinfection. Twelve of 14 eyes recovered 20/50 or better visual acuity. Bacterial superinfections were a serious problem, with a total of six superinfections occurring in three treated eyes.

With timely diagnosis and medical treatment with a combination of antiamebic drugs and avoidance of topical corticosteroids, most cases of Acanthamoeba keratitis can be cured, with an excellent prognosis for visual recovery.