Early Real-World Outcomes Of Polyhexamethylene Biguanide (Phmb) 0.08% Monotherapy For Acanthamoeba Keratitis
Published 2026 - 44th Congress of the ESCRS
Reference: POCOR233 | Type: Free paper | DOI: 10.82333/k86q-9n07
Authors: Ms Nicole Quah* 1 , Mr Scott Hau 2 , Ms Su-Yin Koay 3
1Department of Ophthalmology,Whipps Cross Hospital,London,United Kingdom;Department of Cornea and External Disease,Moorfields Eye Hospital,London,United Kingdom, 2Department of Cornea and External Disease,Moorfields Eye Hospital,London,United Kingdom;Department of Ophthalmology,UCL Institute of Ophthalmology,London,United Kingdom, 3Department of Cornea and External Disease,Moorfields Eye Hospital,London,United Kingdom
Purpose
To describe real-world use, tolerability, and early clinical course of topical polyhexamethylene biguanide (PHMB) 0.08% monotherapy in patients with Acanthamoeba keratitis (AK) at a tertiary referral centre, following abrupt unavailability of compounded PHMB 0.06% due to regulatory supply disruption.
Setting
Moorfields Eye Hospital, London, United Kingdom.
Methods
Retrospective observational real-world evidence series of consecutive patients with AK treated with PHMB 0.08%. Following the closure of the compounding pharmacy supplying PHMB 0.06%, PHMB 0.02% monotherapy was considered sub-therapeutic and would have required addition of a second anti-amoebic agent such as propamidine with potential ocular surface toxicity. A transition to PHMB 0.08% enabled our unit to maintain a monotherapy approach.
Results
50 eyes from 49 patients were treated with PHMB 0.08%. 16 eyes were excluded from analysis due to lack of data (patients only seen once for diagnosis confirmation). 44.1% (15/34) were contact lens–associated and 94.1% (32/34) were unilateral. 38.2% (13/34) had stage 1 disease, 47.1% (16/34) had stage 2 disease, and 14.7% (5/34) had stage 3 disease. Prior anti-amoebic therapy had been used in 47.1% (16/34) as these were pre-existing AK diagnoses. Treatment was well tolerated, with no cessation due to ocular surface toxicity. Adjunctive topical corticosteroids were used in 47.1% (16/34). Clinical resolution was observed in 23.5% (8/34) in the 4 months following the switch to PHMB 0.08% monotherapy.
Conclusions
PHMB 0.08% monotherapy has a clear role in the management of AK and enabled continuation of a monotherapy strategy following disruption to PHMB 0.06% availability, without reliance on additional surface-toxic agents. While definitive conclusions regarding medical cure rates and time to cure cannot yet be drawn due to limited follow-up, early real-world experience supports its use across the AK disease spectrum. Continued follow-up will further define long-term outcomes.