BackgroundAcanthamoeba keratitis (AK) is a serious corneal infection that may even lead to loss of sight. Infection prevalence has increased in recent years as the use of contact lenses (CL) has also increased.PurposeTo analyse if there is a difference in duration and efficacy in treatment with chlorhexidine eye drops 0.02% (CED) in AK alone or associated with Pseudomonas spp. To evaluate the prevalence of AK and use of CL as a risk factor.Material and methodsRetrospective descriptive study in a second-level hospital. Total population of this study was 2 70 000 inhabitants over a period of 3 years (2014 to 2016). Data collected: number of patients treated with CED, demographic data, microbiological results (cultures and PCR for Acanthamoeba spp), days of targeted treatment, need for ocular surgery and use of CL. The treatment was: CED with eye drops of 0.1% propamidine isethionate. Farmatools®patient software was used for data collection and patients’ clinic history.ResultsPatients were treated with CED: 36 (55.5% females). Average age: 35 years (18–90). Microbiological culture results: Acanthamoeba spp eight (22.2%), Acanthamoeba spp together with Pseudomonas spp eight (22.2%), Aspergillus spp 4four (11%), Pseudomonas spp together with Serratia spp four (11%) and pathogens were not isolated 12 (33%). In cultures in which Acanthamoeba spp was isolated, PCR was positive in 12 patients (75%). The average duration of treatment with CED targeted to AK was 201 days (48–268). No one AK without Pseudomonas spp required surgical intervention. All AK together with Pseudomonas spp required surgical intervention. All patients with AK were carriers of CL. The prevalence of AK was one case per 50 000 people/year.ConclusionTreatment with CED was effective in all patients with AK without Pseudomonas spp, but it was not effective in any patient with AK with Pseudomonas spp. The period of treatment with CED in AK was long, for the efficacy it was fundamental to the adherence. This study shows a low prevalence according to the criteria of the World Health Organisation. The use of CL was a risk factor in the appearance of AK. The AK should be one of the first possibilities to consider when a user of CL suffers an atypical keratitis.Reference and/or Acknowledgements1. Ophthalmology. S0161–6420(16):32529–5. doi:10. 1016/j. ophtha. 2017. 05. 012No conflict of interest

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