Diagnosis and management of Acanthamoeba keratitis

Purpose of review This paper reviews the literature generated on Acanthamoeba keratitis since 1998. Recent findings Acanthamoeba infections may be on the rise. Contact lenses are the biggest risk factor for their development. Silicone hydrogel lenses are increasingly prescribed and may be ‘more sticky’ to Acanthamoeba organisms. Orthokeratology for the treatment of myopia has been associated with many new cases of Acanthamoeba keratitis. Daily disposable contact lenses are the safest form of soft contact lens. Patients continue to be misdiagnosed as having herpetic keratitis. Impression cytology and confocal microscopy are newer diagnostic modalities. Topical polyhexamethylene biguanide, chlorhexidine and propamidine are the mainstay of medical therapy. Amniotic membrane may be used for cases of persistent epithelial defect and to control inflammation. Penetrating keratoplasty in a medically treated eye affords a good chance of positive outcome. Summary Acanthamoeba keratitis continues to be a difficult infection to diagnose and manage. The frequency of these infections may be on the rise, most commonly associated with frequent replacement soft contact lenses. The best chance for a good outcome is based on early diagnosis, so it is important for ophthalmologists consider it in patients, especially in the contact lens wearer with suspected herpes simplex keratitis.