Clinical Outcomes in Acanthamoeba Keratitis Treated with Polyhexamethylene Biguanide as Monotherapy

To assess the efficacy of polyhexamethylene biguanide (PHMB) in treating Acanthamoeba keratitis (AK) and also to identify related factors affecting final visual outcome in AK patients treated with PHMB In these interventional case series study, 27 eyes of 25 patients with AK received PHMB 0.02% and divided into two groups according to the final visual acuity (VA); VA equal to or greater than 20/25 and VA less than 20/25. Two groups were evaluated for the effectiveness of PHMB in treatment of AK. Before treatment, more than 85% of eyes had VA of less than 20/25 whilst after treatment final VA was 20/25 or better in 66.7% of eyes. VA regressed in 14.8% of eyes during follow-up and improved or remained the same in more than 85% of eyes. Patients with deep stromal keratitis or a ring infiltrate had more than a 28-fold increase in the odds of a visual outcome worse than 20/25 (OR, 28.0; 95% CI, 3.3-240.8, p=0.001). Patients with Initial VA<20/40 had a 9-fold increase in the odds of a visual outcome worse than 20/25 (OR, 8.6; 95% CI, 1.2-59.8, p=0.003). Longer duration of symptoms (≥ 3 weeks) or the medication used prior the first visit were not associated with poorer final VA (p>0.05). Five eyes (18.5%) finally required keratoplasty. Initial stage of corneal involvement at presentation was the most predictive factors for final visual outcome in AK. Although PHMB, even as monotherapy, is effective in treatment of AK, a remarkable proportion of patients still suffer a final grim visual outcome which require aggressive treatments.