Unilateral Painful Red Eye with Corneal Cysts Assessed with Corneal Confocal Microscopy: A Case Mimicking Acanthamoeba Keratitis

A 28-year-old woman with a history of trauma to her right eye 2 months prior reported experiencing a stinging sensation and tearing in the morning since the injury occurred and the need to occasionally use an eye patch. Three days before presentation she had been prescribed a therapeutic contact lens (CL) with the diagnosis of a corneal epithelial defect. She described significant pain despite the CL. There was a corneal lesion with haze at the base surrounded by corneal edema. Corneal confocal images revealed hyperreflective cystic lesions that suggested Acanthamoeba keratitis (AK). However, the lesion healed within 10 days and the results of cultures taken before the initiation of treatment proved to be negative. The history of trauma and CL wear, the presence of severe pain, corneal findings, and the confocal microscopy detection of cysts led to a suspicion of AK in a differential diagnosis, but the final diagnosis was recurrent epithelial erosion based on the negative culture results, quick response to treatment, and the possibility of similar confocal findings in a healing epithelium. Since AK may cause loss of vision, suspicion should require that samples be obtained for microbiological study and close follow-up of the clinical course until a final diagnosis can be achieved.