Abstracts

Purpose: The number of patients with Acanthamoeba keratitis (AK) encountered in ophthalmological practice seems to be rising, possibly because of an increase in the use of soft contact lenses.The purpose of this study is to give an overview of cases of AK in The Netherlands between 2009 and 2015, to determine whether the incidence of AK is indeed increasing, and to find out what factors significantly influence visual outcome after treatment.Methods: For this retrospective study, all cases of AK occurring in The Netherlands between 2009 and 2015 were collected.Patient characteristics, diagnostic methods and delay, therapy prior to and after diagnosis and visual outcome were obtained from medical files.The primary outcome measurement, treatment failure, was determined as a best corrected visual acuity (BCVA) of <0.3 logMAR (<0.5 Snellen) and/or the need for keratoplasty.Results: Two hundred and thirty-four eyes of 225 patients were included.The average annual increase in amount of cases between 2009 and 2015 was 20.5%.Median age of patients at first presentation was 34 years.Ninety-five percent were contact lens wearers, 74% of them wore soft contact lenses.Diagnosis was based on culture, PCR, confocal microscopy or pathology (following biopsy or keratoplasty) in 93%.The median total delay from start of complaints until diagnosing AK was 30 days (range 2-319).In 65% corticosteroid therapy was applied before diagnosis.After diagnosis, treatment consisted of a combination of chlorhexidine and propamidine isethionate (Brolene) in most cases.A therapeutic keratoplasty was required in 22%.Of 216 eyes a final BCVA was known, after a median follow-up duration of 353 days (range 12-1682).Six of them had no light perception, five could perceive light but no hand movements.The other 205 eyes had a median BCVA of 0.08 logMAR (0.83 Snellen).Hundred and six eyes (45%) met the criteria for treatment failure.In a multivariable regression analysis, higher age at presentation and corticosteroid use before diagnosis were correlated with treatment failure.Conclusion: Although Acanthamoeba keratitis is still a relatively uncommon disease, the incidence has clearly increased from 2009 until 2015.Almost all cases (95%) were associated with contact lens use.Nearly half of the cases resulted in treatment failure, with age and corticosteroid use before diagnosis as important risks factors.