[Acanthamoeba keratitis caused by extended wear contact lenses]

A 68 year old female with aphakic soft lenses on an extended wear basis developed an Acanthamoeba-keratitis. The diagnosis could be confirmed by a positive culture of a corneal smear, the contact lens and the care solution. Immediate antibiotic therapy including aminoglycosides and cephalosporines topically showed response with clearing of the stromale infiltrates and, as a residuum, the development of small stromal scars at the former site of inflammation. An Acanthamoeba-keratitis should be considered in the differential diagnosis of all cases of keratitis in contact lens wearers that are unresponsive to topical medical therapy and without bacterial growth on routine cultures.