clinical outcomes in acanthamoeba keratitis treated with polyhexamethylene biguanide as monotherapy

purpose: 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 methods: 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. results: before treatment, more than 85% of the 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 the 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 [odd ratio (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.  conclusion: initial stage of corneal involvement at presentation was the most predictive factor 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 requires aggressive treatments.    iranian journal of ophthalmology 201426(1):41-47 © 2014 by the iranian society of ophthalmology