Acanthamoeba Keratitis: Recent Advances in Diagnosis and Management
Antonio Z. Diaz, Isabell Kassaye, Jeremy D. KeenanPurpose:
To review recent advances in the diagnosis and management of acanthamoeba keratitis (AK), emphasizing clinically relevant developments from the past 5 years.
Methods:
A scoping review of PubMed and ClinicalTrials.gov was conducted for studies published between July 2020 and December 2025 using the terms “acanthamoeba AND (diag* OR test* OR treatment).” Clinical studies and studies of human AK specimens were prioritized. A total of 814 publications and 11 clinical trial listings were screened, with 128 full-text articles reviewed.
Results:
Recent diagnostic advances included artificial intelligence models developed for in vivo confocal microscopy images and anterior segment photographs. Polymerase chain reaction (PCR) assays demonstrated sensitivity similar to or greater than culture while maintaining high specificity. Emerging modalities included next-generation sequencing, viability PCR assays, and antibody-based diagnostics. Recent studies on acanthamoeba treatment include the Orphan Drug for Acanthamoeba Keratitis (ODAK) trial, which randomized eyes to polyhexamethylene biguanide (PHMB) 0.08% monotherapy or PHMB 0.02% plus propamidine 0.1% combination therapy, and found similar 12-month cure rates and visual outcomes in the two groups, and better-than-expected outcomes using a standardized protocol. Adjunctive therapies including topical voriconazole, Rose Bengal Photodynamic Antimicrobial Therapy, miltefosine, and povidone-iodine showed potential benefit, although evidence was limited primarily to observational studies and small clinical trials. Surgical management strategies, including penetrating and lamellar keratoplasty, demonstrated variable recurrence rates, and the optimal timing of keratoplasty remains uncertain.
Conclusions:
New diagnostic technologies and standardized PHMB-based treatment protocols may improve outcomes for AK. Evidence is more limited for a range of other potential therapies.