Ring infiltrates in Pythium keratitis

Abstract This study highlights the clinical presentation of ring infiltrates (RI) in Pythium keratitis, typically associated with fungal or Acanthamoeba keratitis, emphasizing diagnostic and therapeutic challenges. We present a retrospective case series of seven patients diagnosed with Pythium keratitis who developed RI, either at presentation or during the disease course. Diagnosis was confirmed by microbiological examination, and all patients received antipythium therapy within 1 week of presentation. Among the seven patients, all exhibited RI, leading to diagnostic confusion due to its common association with fungal and Acanthamoeba keratitis. Prompt microbiological confirmation enabled targeted therapy, but initial presentation caused diagnostic challenges, especially in settings without routine microbiological support. RI is not uncommon in Pythium keratitis and can result in misdiagnosis as fungal keratitis, particularly in resource-limited settings. Recognizing RI as a feature of Pythium keratitis and ensuring early microbiological confirmation can enhance diagnostic accuracy and improve patient outcomes.